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Title: The life of Isambard Kingdom Brunel, Civil Engineer

Author: Isambard Brunel

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Most recently updated: October 23, 2024

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*** START OF THE PROJECT GUTENBERG EBOOK THE LIFE OF
ISAMBARD KINGDOM BRUNEL, CIVIL ENGINEER ***

Painted by J. C. Horsley, R.A.—Engraved by T. O. Barlow.
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THE LIFE
OF
ISAMBARD KINGDOM

BRUNEL,
CIVIL ENGINEER.

BY

I S A M B A R D B R U N E L, B.C.L.,
OF LINCOLN’S INN;
CHANCELLOR OF THE DIOCESE OF ELY.

LONDON:
LONGMANS, GREEN, AND CO.
1870.

PREFACE.
I HAVE NOT attempted to describe the events of my father’s life in
chronological order beyond the end of Chapter III., which brings down the
narrative to the close of 1835, the year in which the Act was obtained for
the Great Western Railway.

Chapter IV. contains a general account of my father’s railway works,
with the exception of the Bridges, which are described in Chapter VII. The
history of the Broad Gauge and of the trial of the Atmospheric System on
the South Devon Railway is given in Chapters V. and VI.

Chapters VIII.—XIII. contain an account of my father’s labours for the
advancement of Ocean Steam Navigation. It will be noted that these
chapters cover the same period as Chapters IV.—VII., namely, from 1835,
the year of the commencement of the Great Western Railway and the ‘Great
Western’ Steam-ship, to 1859, the year of his death, in which the Saltash
Bridge and the ‘Great Eastern’ were both completed.

Chapters VII. (on the Bridges) and XIV. (on the Docks) have been
written by Mr. William Bell, for many years a member of my father’s
engineering staff; and in regard to Chapter V. (on the Broad Gauge), I have
to acknowledge assistance rendered me by Mr. William Pole, F.R.S.

For the Note on the Carbonic Acid Gas Engine which follows Chapter I.,
I am indebted to Mr. William Hawes; and for Chapter VI. (on the
Atmospheric System) to Mr. Froude, F.R.S.

I have also printed letters, written to me at my request, relating to
various incidents in my father’s life.

The assistance I received in the preparation of the chapters on Steam
Navigation from my friend the late Captain Claxton, R.N., has been referred

to in the note to p. 234.

I have throughout availed myself of my brother’s professional
knowledge.

I have been compelled, in order to bring the work within the compass of
a single volume, to omit much that would otherwise have been inserted, and
I must therefore be held responsible for the general arrangement of those
parts which have been contributed by others, as well as for the chapters
which I have written myself.

Lastly, I desire gratefully to thank those friends who, by supplying me
with materials and revising the proof sheets, have helped me in my
endeavour to make this book, as far as possible, an accurate record of my
father’s life, written in the spirit of which he would have approved.
I. B.
18 Duke Street, Westminster:
November, 1870.

CONTENTS

PAGE

List of Reports and Other Original Documents xvii
List of Illustrations xxvii
CHAPTER I.
EARLY LIFE.
A.D. 1806—1828.
Birth of Mr. Brunel, April 9, 1806—Sir Marc Isambard Brunel—The
Block Machinery—Mr. Brunel’s School Life—The Thames Tunnel
—Sinking of the Rotherhithe Shaft—Description of the Shield—
Extracts from Sir Isambard Brunel’s Journals from the
Commencement of the Thames Tunnel to the date of the Second
Irruption of the River, January 12, 1828—Note A: The Bourbon
Suspension Bridges—Note B: Experiments with Carbonic Acid
Gas. 1
CHAPTER II.
THE CLIFTON SUSPENSION BRIDGE.
A.D. 1829—1853. ÆTATIS 24—48.
Origin of the Undertaking—The First Competition, November 1829
—Description of Mr. Brunel’s Plans—Mr. Telford’s Decision as
Umpire—Mr. Telford’s Design—The Second Competition—Mr.
Brunel appointed Engineer, March 1831—Commencement of the
Works, August 1836—Description of the Design—Abandonment
of the Works, 1853—Formation of a New Company and
Completion of the Bridge, 1864—Note: The Hungerford
Suspension Bridge 46
CHAPTER III.
EARLY HISTORY OF THE GREAT WESTERN RAILWAY.
A.D. 1833—1835. ÆTATIS 27—30.

Sketch of the History of Railways in England prior to 1833—The
Stockton and Darlington—The Liverpool and Manchester—The
London and Birmingham—Proposed Railway between London and
Bristol—Mr. Brunel appointed Engineer, March 7, 1833—Survey
of the Line—Unsuccessful Application to Parliament in 1834—
Successful Application in 1835—Reminiscences of Mr. Brunel,
1833-1835—Extract from Mr. Brunel’s Diary, written at the close
of 1835 61
CHAPTER IV.
RAILWAY WORKS.
A.D. 1835—1859. ÆTATIS 30—54.
Construction of the Great Western Railway—The Box Tunnel—The
Bath and Bristol Stations—The Paddington Station—The Great
Western Hotel—Branches and Extensions of the Great Western
Railway—The Bristol and Exeter Railway—Railways in
Devonshire and Cornwall—Railways to Basingstoke, to
Weymouth, and to Salisbury—In South Wales—In Ireland—In
Italy—In India—Supervision of Works—Mr. Brunel’s Engineering
Staff—His Reputation as a Witness—Reminiscences of Mr. Brunel,
1835-1838 79
CHAPTER V.
THE BROAD GAUGE.
Origin of the Ordinary Gauge of Railways—Adoption by Mr. Brunel
of the Broad Gauge on the Great Western Railway—Reasons for its
Adoption—The Permanent Way—Reports of Mr. Nicholas Wood
and Mr. John Hawkshaw, 1838—Extract from Report of Directors
of Great Western Railway Company (December 20, 1838)—
Extension of the Broad Gauge System—Break of Gauge—Royal
Commission on the Gauge of Railways, 1845—Letter of Mr.
Brunel on the Broad Gauge (August 6, 1845)—Gauge Act of 1846
—The Mixed Gauge—Report of Railway Commissioners, 1847—
Northern Extensions of the Great Western Railway—Advantages
of the Broad Gauge—Partial Abandonment of the Broad Gauge 99
CHAPTER VI.

THE ATMOSPHERIC SYSTEM.
A.D. 1840—1848. ÆTATIS 35—43.
Preliminary Observations—The South Devon Railway—Description
of the Atmospheric System—History of its Introduction prior to
1844—Report by Mr. Brunel, recommending its Adoption on the
South Devon Railway (August 19, 1844)—Examination of this
Report—Mr. Brunel’s Evidence before the Select Committee on
Atmospheric Railways, 1845—History of the Application of the
System on the South Devon Railway, 1844-1848—Report on State
of Works (August 28, 1847)—Report on Causes of Failure (August
19, 1848)—Abandonment of the System, September 1848—Note:
Comparison of Stationary and Locomotive Power 131
CHAPTER VII.
RAILWAY BRIDGES AND VIADUCTS.
1. Brickwork and Masonry Bridges—Hanwell Viaduct—
Maidenhead Bridge—Flying Bridges—Letter from Mr. Brunel on
Bridge Construction (December 30, 1854)—2. Timber Bridges—
Sonning Bridge—Bath Bridge—Stonehouse Viaduct—Bourne
Viaduct—St. Mary’s Viaduct—Viaducts on the South Devon
Railway—Ivy-bridge—Viaducts on the South Wales Railway—
Newport—Landore—Viaducts on the Cornwall Railway—St.
Pinnock—Viaducts on the West Cornwall and Tavistock Railways
—Preservation of Timber—3. Cast-iron Bridges—Letter on Use of
Cast Iron (April 18, 1849)—Hanwell Bridge—Experiments on
Cast-iron Girders—Extract from Letter to Secretary of Commission
on Application of Iron to Railway Structures (March 13, 1848)—4.
Wrought-iron Bridges—Girder Bridges—Experiments on
Wrought-iron Girder—Opening Bridges—Trussed Bridges—
Newport Viaduct—Windsor Bridge—Chepstow Bridge—Method
of Sinking the Cylinders—Description of the Main Truss—The
Floating Operations—The Royal Albert Bridge at Saltash—The
Centre Pier—Description of the Superstructure—The Floating and
Raising of the Trusses—Opening of the Bridge by H. R. H. the
Prince Consort—Note: Experiments on Matters connected with
Bridge Construction 171

CHAPTER VIII.
STEAM NAVIGATION. THE ‘GREAT WESTERN’ STEAM-SHIP.
A D. 1835—1847. ÆTATIS 30—42.
Introduction to the Chapters on Steam Navigation—Formation of the
Great Western Steam-Ship Company—Commencement of the
Building of the ‘Great Western’—Report on Selection of the
Builders of the Engines (June 18, 1836)—Statements of Dr.
Lardner on the probable Failure of a line of Steam-ships between
England and America—Voyage of the ‘Great Western’ to London
—Completion of the Engines—Her return to Bristol—Fire on
Board, and Accident to Mr. Brunel—Voyage to New York—
Comparison between the Performances of the ‘Great Western’ and
the ‘Sirius’—Subsequent History of the ‘Great Western’—Note:
Dimensions of the Ship and Engines 231
CHAPTER IX.
STEAM NAVIGATION. THE ‘GREAT BRITAIN’ STEAM-SHIP.
A.D. 1838—1847. ÆTATIS 33—42.
Commencement of the building of the ‘Great Britain’—Report on
the Engines (June 13, 1839)—Experiments on the Screw Propeller
—Its Adoption in the ‘Great Britain’—Completion of the Ship—
Her Voyage across the Atlantic—Stranding of the ‘Great Britain’ in
Dundrum Bay—Letter to Captain Claxton on the Condition of the
‘Great Britain’ and on the Means to be adopted for saving her
(December 10, 1846)—Report to the Directors on the same Subject
(December 14, 1846)—Appointment of Captain Claxton to
superintend the Execution of Mr. Brunel’s Plans—Letter to
Captain Claxton on the Difficulties to be overcome (December 29,
1846)—Report enclosing Captain Claxton’s Account of the
Erection of the Breakwater (February 27, 1847)—Report on the
Arrangements for Floating off the Ship (May 4, 1847)—Successful
Accomplishment of the Floating Operations—Subsequent History
of the ‘Great Britain’—Note: Dimensions of the Ship and Engines 246
CHAPTER X.
STEAM NAVIGATION. INTRODUCTION OF THE SCREW PROPELLER
INTO THE ROYAL NAVY.

A.D. 1841—1844. ÆTATIS 36—39.
Appointment of Mr. Brunel to conduct Experiments for the
Admiralty with various Forms of the Screw Propeller, April 1841—
Trials with the ‘Polyphemus’—Opposition to Mr. Brunel’s
Experiments—Trials with the ‘Rattler’, October 1843—October
1844 283
CHAPTER XI.
STEAM NAVIGATION. THE ‘GREAT EASTERN’ STEAM-SHIP, FROM
THE COMMENCEMENT OF THE UNDERTAKING TO THE LAUNCH.
A.D. 1851—1857. ÆTATIS 46-52.
Introductory Observations—The Australian Steam Navigation
Company—Statement of Mr. Brunel’s Project of a Line of large
Ships (June 10, 1852)—Adoption of his Plans by the Eastern Steam
Navigation Company—Extract from a Letter describing the
Scheme (July 1, 1852)—Letter to J. Scott Russell, Esq., on the
Form and Dimensions of the Great Ship (July 13, 1852)—Report
on Mode of Proceeding (July 21, 1852)—Report on Enquiries
Relating to the Draught and Form of the Vessel (October 6, 1852)
—Report on the Proceedings of the Committee appointed to
consider Mr. Brunel’s Plans (March 21, 1853)—Tenders invited for
the Ship and Engines—Report on Tenders (May 18, 1853)—
Preparation of the Contracts and Specifications—Extracts from Mr.
Brunel’s Memoranda (A.D. 1852, 1853, 1854)—Letter on his
Position and Duties as Engineer of the Company (August 16,
1854)—Letter on an Article in a Newspaper (November 16, 1854)
—Report on the Undertaking (February 5, 1855)—Arrangements
proposed for obtaining Astronomical Observations—Letter to G. B.
Airy, Esq., Astronomer Royal (October 5, 1852)—Appointment of
Mr. William Harrison to the Command of the Ship—Memorandum
on the Management of the Great Ship (October 1855)—Letter on
the Duties of the Chief Engineer (March 19, 1857)—Suspension
and Resumption of the Works 289
CHAPTER XII.
STEAM NAVIGATION. THE ‘GREAT EASTERN’ STEAM-SHIP. THE
LAUNCH.

A.D. 1857, 1858. ÆTATIS 52.
Determination that the Ship should be launched broadside to the
River—And that the Launch should be slow—Extracts from Mr.
Brunel’s Report of February 1855—Reasons for the Adoption of
Iron Sliding Surfaces—Description of the Ways and Cradles—And
of the Motive Power provided for launching the Ship—
Memorandum on proposed Arrangements for the Launch
(September 26, 1857)—Letter to Captain Harrison on River Tackle
(September 30, 1857)—Letter on the Nature of the Operations
(October 23, 1857)—Memorandum on general Arrangements and
intended Mode of Proceeding (October 30, 1857)—History of the
Launch, Nov. 3, 1857 to January 31, 1858—Letter to the Directors
(November 26, 1857)—Report and Memorandum on the
Launching Operations (December 17, 1857)—Floating the Ship—
Note A: Experiments and Observations on Friction—Note B: Letter
to W. Froude, Esq. (February 2, 1858) 340
CHAPTER XIII.
STEAM NAVIGATION. THE ‘GREAT EASTERN’ STEAM-SHIP.
COMPLETION AND SUBSEQUENT HISTORY.
A.D. 1858, 1859. ÆTATIS 52-54.
A.D. 1859-1870.
Preparations for completing the Ship—Formation of the Great Ship 392
Company—Mr. Brunel’s Absence from England—Progress of the
Works from his Return to his last Illness—Voyage to Weymouth—
Explosion of Water-Heater—Storm at Holyhead—Description of
the Ship—Her first Voyage to New York, June 1860—Second
Voyage to New York, May 1861—Voyage with Troops to Quebec,
June 1861—Fracture of Rudder Head and Destruction of
Paddlewheels, September 1861—Voyages in 1862—Accident off
Montauk Point, August 27, 1862—Voyages in 1863—Formation of
the Great Eastern Steam-Ship Company—Remarks on the History
of the ‘Great Eastern’ previous to her Employment in laying
Submarine Telegraph Cables—Telegraph Expeditions of 1865 and
1866—French Cable Expedition of 1869—Voyage to Bombay and

Aden, 1869, 1870—Concluding Remarks—Note: Dimensions of
the Ship and Engines
CHAPTER XIV.
DOCK AND PIER WORKS.
A.D. 1831—1859. ÆTATIS 26—54.
Monkwearmouth Docks, 1831—Bristol Docks—Floating Harbour,
1832—Proposed Works at Portishead—New Lock at Bristol, 1845
—Bristol Dock Gates—Plymouth Great Western Docks, 1847—
Briton Ferry Docks, 1851—Brentford Dock, 1856—Pier at Milford
Haven, 1857 417
CHAPTER XV.
MISCELLANEOUS WORKS.
The Great Exhibition of 1851—The Crystal Palace Water Towers,
1853—Polygonal Rifle, 1852—Gunnery Experiments, 1854—
Floating Gun-Carriage, 1854—Renkioi Hospital Buildings, 1855 445
CHAPTER XVI.
MR. BRUNEL’S PROFESSIONAL OPINIONS AND PRACTICE.
Scheme of the Chapter—Mr. Brunel’s Position in relation to the 474
Companies of which he was Engineer—Letter on the Direction of
Railway Works in Italy (March 4, 1845)—Letter on the Position of
Joint Engineer (October 16, 1843)—Letter on the Position of
Consulting Engineer (December 30, 1851)—Letter on the Position
of the Engineer in relation to the Contractors (May 26, 1854)—
Letters on the Position of the Engineer in relation to the Directors
(April 15, 1850, December 6, 1851, January 22, 1857)—Mr.
Brunel’s Assistants—Letters on Interference of Directors with the
Assistant Engineers (January 19, 1842, January 28, 1842, January
12, 1851)—Mr. Brunel’s Pupils—His Relations with other
Engineers—Inventors—Letter in reply to an Inventor (September
17, 1847)—Mr. Brunel’s Views as to State Interference—Letter on
the Royal Commission on the Application of Iron to Railway
Structures (March 13, 1848)—Letter on a Proposal to obtain the
Recognition in England of Decorations conferred at the Paris
Exhibition of 1855 (February 9, 1856)—Mr. Brunel’s Opinion on

the Patent Laws—Memorandum for Evidence before the Select
Committee of the House of Lords on the Patent Laws, 1851—
Extract from Observations on the Patent Laws, made by Mr. Brunel
at a Meeting of the Society of Arts, March 26, 1856
CHAPTER XVII.
PRIVATE LIFE.
Reminiscences of Mr. Brunel’s Private Life—Removal to 18 Duke
Street, Westminster—His Marriage, 1836—Special Constable in
1848—Mr. Brunel’s Love of Art—His Journey to Italy, 1842—
Accident with the Half-Sovereign, 1843—Purchase of Property in
Devonshire, 1847—His life at Watcombe—The Launch of the
‘Great Eastern,’ 1857—Mr. Brunel’s Failing Health—Journeys to
Switzerland and Egypt, 1858—Letter from Philæ (February 12,
1859)—His last Illness—His Death, September 15, 1859—Funeral
—Address of Joseph Locke, Esq., M.P., at the Institution of Civil
Engineers, November 8, 1859 499
APPENDIX I.
Report to the Directors of the Great Western Railway on the Broad
Gauge, &c. (August 1838) 525
APPENDIX II.
Report to the Directors of the Great Western Steam-Ship Company,
recommending the Adoption of the Screw Propeller in the ‘Great
Britain’ Steam-ship (October 1840) 539
INDEX 559

LIST

OF

REPORTS AND OTHER ORIGINAL DOCUMENTS.

PAGE
1. Extract from Mr. Brunel’s Diary (December 26, 1835) 78
2. Letter on the Box Tunnel (June 21, 1842) 81
3. Extract from Report to Directors of the Great Western
Railway Company on Break of Gauge (December 13,
1838) 105
4. Extract from Report to Directors of the Great Western
Railway Company on the Permanent Way (February
1837) 109
5. Letter on various Points relating to the Broad Gauge
(August 4, 1845) 120
6. Extract from Letter on Atmospheric System (April 8,
1844) 137
7. Report to the Directors of the South Devon Railway
Company, recommending them to adopt the Atmospheric
System (August 19, 1844) 138
The question had been frequently considered by him (p.
138)—Stationary power is cheaper and otherwise better
than locomotive power (p. 138)—The Atmospheric
System is a good, economical mode of applying stationary
power (p. 138)—Reasons for considering it applicable to
the South Devon Railway (p. 139)—In the construction of
the line (p. 140)—In the subsequent working (p. 141).
8, 9. Letters on giving Evidence before the Select Committee
of the House of Commons on the Atmospheric System
(March 31, 1845; April 3, 1845) 145

10. Report to the Directors of the South Devon Railway on
the State of the Atmospheric Apparatus (August 27, 1847) 149
Regret at postponement of working (p. 149)—Which has
been caused by delay in completion of the engines (p.
149)—Experimental trains have run (p. 149)—Difficulties
have exceeded all just anticipations (p. 150).
11. Report to a Committee of the Directors of the South
Devon Railway Company on the Causes of the Failure of
the Atmospheric System (August 19, 1848) 159
The first difficulty has been in the stationary engines,
which have consumed an excessive amount of fuel (p.
159)—The difficulties in the working of the longitudinal
valve have been more numerous (p. 161)—The principal
evil might be remedied in a new valve (p. 162)—An
extension of the system beyond Newton cannot be
recommended (p. 162)—The delay in obtaining the
telegraph has been a great disappointment (p. 163).
12. Letter on the Design of Engineering Works (December 30,
1854) 178
13. Extract from Letter on the Use of Cast Iron in Bridge
Construction (April 18, 1849) 190
14. Extract from Letter on the same Subject (March 13, 1848) 192
15, 16, 17. Extract from Letters on Bridges of Large Spans (January
31, 1852; December 1, 1852; May 30, 1854) 212
18. Extract from Report on the Cornwall Railway as to
making the Saltash Bridge for a Single Line (February 5,
1852) 214
19. Report to the Directors of the Great Western Steam-Ship
Company on the Selection of the Builders of the Engines
for the ‘Great Western’ Steam-ship (June 18, 1836) 235
Every means must be taken to secure the best engines
possible in this the boldest attempt yet made (p. 235)—
The peculiar conditions required in these engines (p. 235)
—They must, as far as is possible, be perfect in all their
details from the moment of their completion (p. 235)—

The machinery required is by no means an ordinary
steam-engine (p. 236)—Modifications necessary in
designing engines of so large a size (p. 236)—Reasons
based on these considerations for preferring Messrs.
Maudslay and Field as builders of these engines (p. 236).
20. Letter on the Engines for the ‘Great Britain’ Steam-ship
(June 12, 1839) 249
Both the plans of Messrs. Maudslay and Field and Mr.
Humphrys are adapted to the case, and the choice will
depend upon the relative cost and advantages of forming
an establishment to build the engines, and that of having
the skill of experienced manufacturers (p. 249).
21. Letter to T. R. Guppy, Esq., on the Construction of Iron
Ships (August 3, 1843) 259
22. Extract from Letter on the ‘Great Britain’ Steam-ship
(December 11, 1844) 261
23. Letter to Captain Claxton on the State of the ‘Great
Britain’ Steam-ship (December 10, 1846) 264
24. Report on the Condition of the ‘Great Britain’ Steam-ship
when stranded in Dundrum Bay (December 14, 1846) 267
The ship is, apart from mere local damage, perfectly
sound, which would not have been the case had she been
built of timber (p. 267)—Description of her injuries (p.
268)—Consideration of the best means of recovering the
property invested in her—It would not be profitable to
break her up (p. 268)—How, then, is the vessel to be got
into port? (p. 269)—This question is secondary to that of
how she is to be preserved until she can be removed (p.
269)—A stiff timber breakwater would not stand, even if
it could be safely constructed (p. 269)—The best plan is to
form under the stern and along the exposed side of the
ship a mass of fagots (p. 270)—And in order to preserve
the ship, this must be done without delay (p. 270)—As to
floating her off, she should be lifted and made water-tight
(p. 271)—But she must first be preserved (p. 272).

25. Letter to Captain Claxton on the Breakwater (December
29, 1846) 272
26. Report enclosing Captain Claxton’s Account of the
Proceedings at Dundrum (February 27, 1847) 273
Success achieved by Captain Claxton in constructing the
breakwater of fagots (p. 273)—Introduction by him of
several important alterations and improvements in the
plans proposed (p. 274).
27. Report on the proposed Means of Floating the ‘Great
Britain’ Steam-ship (May 4, 1847) 278
The ship has been successfully protected and lifted, and
made water-tight, so that the operation of floating by
camels becomes more practicable (p. 279)—The Directors
would do well to call in Mr. Bremner to advise them (p.
280).
28. Extract from Letter relating to Proceedings at the
Admiralty as to the Screw Propeller (July 8, 1842) 283
29. Extract from Letter on the same Subject (August 6, 1842) 286
30. Statement of Project for a Line of large Steam-ships (June
10, 1852) 292
The principle advocated is that of making the vessel large
enough to carry her own coal for the voyage, just as the
‘Great Western’ steam-ship did in 1838 (p. 292)—The size
being limited only by the extent of demand for freight,
and by the circumstances of the ports to be frequented (p.
292).
31. Extract from Letter describing the Project of the Great
Ship (July 1, 1852) 293
32. Letter to J. Scott Russell, Esq., on the Form and
Dimensions of the Great Ship (July 13, 1852) 294
33. Report to the Directors of the Eastern Steam Navigation
Company on mode of Proceeding (July 21, 1852) 296
34. Report on Enquiries relating to the Draught and Form of
the Great Ship (October 6, 1852) 297

35. Report on the Dimensions of the Great Ship (March 21,
1853) 299
36. Report on the Tenders for the Ship and Engines (May 18,
1853) 301
A short specification was drawn up for the engines, and
detailed drawings and specifications for the ship (p. 301)
—Tenders have been received for the engines from Mr. J.
Scott Russell, Messrs. Watt and Co., and Mr. Humphrys
(p. 302)—After frequent communications with these
gentlemen, Messrs. Watt and Co.’s designs are preferred
for the screw engines, which will be the largest yet made,
and on which will mainly depend the performances of the
ship (p. 302), and Mr. J. Scott Russell’s for the paddle
engines (p. 302)—As regards a tender for the ship, after
communications with several parties, the result is a tender
from Mr. J. Scott Russell (p. 303).
37. Extracts from Mr. Brunel’s Memoranda relating to the
‘Great Eastern’ Steam-ship (July 11, 1852, to November
18, 1853) 304
July 11, 1852: Dimensions of the ship (p. 304)—Division
of power between the screw and paddle engines (p. 305)
—Every known means must be adopted to ensure
efficiency (p. 305)—Jacketing of steam pipes, &c. (p.
305). July 17, 1852: Conference with Mr. Field as to
division of power between the screw and paddle engines
(p. 305)—Pressure of steam (p. 305)—Nothing uncertain
must be risked (p. 305)—Jacketing (p. 305). July 19,
1852: Strong bulkheads every 30 feet or thereabouts, and
the main ribs, and even at least two main deck beams, to
be longitudinal, instead of transverse (p. 305). February 2,
1853: Present views as to the construction of the ship and
engines (p. 306)—Boilers (p. 307)—Advantages of
oscillating engines for both screw and paddle engines (p.
307). February 21, 1853: Proper dimensions for the
Calcutta line (p. 308)—Gas (p. 308)—Ventilation (p. 308)
—Steering (p. 308). March 14, 1853: Dimensions now

determined on (p. 308). March 22, 1853: Various
dimensions settled (p. 308). April 28, 1853: Tenders are
being sought for (p. 308)—Arrangements for measuring
the coal (p. 309)—Use of clean water (p. 309). August 7,
1853: Memoranda for engines (p. 309). November 18,
1853: Governors (p. 309)—Auxiliary engine and boiler
(p. 309).
38. Extracts from Mr. Brunel’s Memoranda relating to the
‘Great Eastern’ Steam-ship (February 25 to March 10,
1854) 310
February 25, 1854: Thought and labour involved in the
details of the construction both of the ship and engines (p.
310)—Cabin arrangements (p. 310)—Economy of
material in the construction of the ship (p. 310)—A matter
generally neglected in shipbuilding (p. 310)—All this
misconstruction forbidden (p. 311). March 3, 1854:
Details of screw engines (p. 311). March 10, 1854: Details
of ship (p. 311).
39. Letter to the Secretary of the Eastern Steam Navigation
Company, on Position as Engineer of the Company
(August 16, 1854) 311
His unusual stake in the undertaking, and the heavy
responsibility he has incurred (p. 311)—The work is one
which requires that it should be entirely under his
individual management and control (p. 312)—And
therefore there must be no other adviser or source of
information on any question connected with the
construction or mode of carrying out the work (p. 312).
40. Letter to the same on an Article in a Newspaper
(November 16, 1854) 313
His general rule is not to notice newspaper articles, but
this one bears the stamp of authority (p. 313)—Marked
care is shown in depreciating his former efforts in
advancing steam navigation, and in representing him, in
the present case, as the passive approver of the project of
another (p. 313)—Whereas it originated solely with him,

and has been worked out by him with great thought and
labour (p. 314).
41. Report to the Directors of the Eastern Steam Navigation
Company, describing the Nature of the Undertaking
(February 5, 1855) 315
Labour of preparing the preliminary designs for the ship
(p. 316)—[Proposed arrangements for launching]—
Principal peculiarities in the construction of the ship (p.
316)—Water-tight compartments (p. 316)—Transverse
bulkheads (p. 316)—Double skin (p. 317)—Longitudinal
bulkheads (p. 318)—Economy in materials (p. 318)—
Engines (p. 318)—Boilers (p. 319)—The best advice has
been sought on every point (p. 319)—The position and
design of the paddlewheels (p. 319)—The screw propeller
—(p. 320)—Protection from fire (p. 320)—Masts and
sails (p. 320)—Astronomical observations (p. 320)—
Lightning conductors (p. 321)—Adjustment of compasses
(p. 321).
42. Letter to G. B. Airy, Esq., Astronomer Royal (October 5,
1852) 321
As so much depends on perfect navigation, every means is
to be taken to ensure a constant determination of the ship’s
position and course (p. 321)—It is proposed to have an
observatory and staff of observers to be constantly
engaged in taking observations (p. 322)—What should be
the nature of these observations and of the instruments
required? (p. 322).
43. Memorandum on the Management of the Great Ship
(October 1855) 324
The principles to be followed in the use of this new
machine, and the qualifications of the commander, have
long been a subject of anxious consideration by him (p.
324)—This ship requires a totally different management
from that suited to ordinary vessels (p. 325)—Examples
of this proposition (p. 326)—Size of the great ship (p.
326)—By no possibility must she be allowed to touch the

ground (p. 327)—Probable effects of the great size and
mass of this vessel (p. 329)—And of her speed (p. 330)—
The proposed system of continuous observation (p. 330)
—The exact course the ship is to take must be determined
previously to the voyage, and must be strictly adhered to
(p. 331)—Economy of fuel another consideration of the
highest importance (p. 332)—Proper speed of the engines
(p. 332)—Use of the sails (p. 333)—Peculiarities of the
position of the commander (p. 333)—His attention must
be devoted exclusively to the general management of the
system by which the ship is to be made to go like a piece
of machinery (p. 333)—His assistants (p. 334)—Four
chief officers (p. 334)—A master at the head of a staff of
observers, who are to make continuous observations upon
the position and performances of the ship (p. 334)—The
chief engineer (p. 335)—The principles herein set out are
to be adopted by the commander as the guide of his
conduct in working this machine (p. 335).
44. Letter on the Responsibility of his Position (sent with last) 324
45. Letter on the Duties of the Chief Engineer of the Great
Ship (March 19, 1857) 335
The success of the ship as a steamboat will depend
entirely upon the amount of power developed by the
engines in proportion to the fuel consumed (p. 336)—The
peculiar duties of the chief engineer will be to obtain the
largest amount of steam from the defined expenditure of
fuel, and the use of this steam so as to obtain the largest
amount of power and the largest amount of result (p. 337)
—Accurate measurements required of fuel expended and
results obtained (p. 337)—Economy in every department
may make the difference between the success and failure
of the ship (p. 337)—The chief engineer should, if
possible, superintend the erection of the engines (p. 338).
46. Extract from Report to the Directors of the Eastern Steam
Navigation Company, describing the proposed
Arrangements for Launching (February 5, 1855) 341

Reasons for deciding to launch the ship sideways (p. 341)
—And probably gradually (p. 342).
47. Extract from Memorandum as to Power required to move
the Ship (September 26, 1857) 352
48. Letter to Captain Harrison on the River Tackle (September
30, 1857) 354
49. Letter to the Directors of the Eastern Steam Navigation
Company on the Nature of the Launching Operations
(October 23, 1857) 355
The date is uncertain (p. 355)—The ship is to be lowered
down and floated off by a slow and laborious operation (p.
355)—She may stop or not move at all (p. 356).
50. Memorandum on General Arrangements and intended
Mode of Proceeding in the Launching Operations
(October 30, 1857) 356
51. Letter to the Directors of the Eastern Steam Navigation
Company on the State of the Operations (November 26,
1857) 366
52. Letter to the Directors, and Memorandum on the State of
the Operations (December 17, 1857) 377
53. Letter to W. Froude, Esq., describing the Floating of the
‘Great Eastern’ (February 2, 1858) 389
54. Extract from Report to the Directors of the Bristol Dock
Company on the Condition of the Floating Harbour
(August 31, 1832) 423
55. Extract from Report on the same subject (January 31,
1842) 424
56. Extract from Report on Portishead Pier (December 26,
1839) 427
57. Letter on the Distribution of Prizes, addressed to the
Chairman of the Committee of the Section of Machinery
of the Exhibition of 1851 (March 11, 1850) 445
58. Extract from Report of the Jury of Class VII. of the
Exhibition of 1851 on Sir Joseph Paxton’s Design for the
Building 447

59, 60, 61. Letters to Westley Richards, Esq., on the Polygonal Rifle
450-
(October 25, 1852; February 7, 1853; November 26,
1
1858)
62. Extract from Letter to James Nasmyth, Esq., on the
Construction of Large Guns (April 2, 1855) 452
63. Extract from Letter to W. G. Armstrong, Esq., on the Wire
Gun (June 8, 1855) 454
64. Memorandum on the Floating Gun-Carriage (December
20, 1855) 455
The principle is fixing a very heavy gun in a floating shot-
proof chamber (p. 455)—Mode of working the gun (p.
455)—Mode of manœuvring the vessel (p. 456)—Mode
of attacking the Baltic forts with a fleet of such vessels (p.
457)—Thickness of iron required to make the vessel shot
proof (p. 458)—Best manner of constructing the vessels
(p. 458).
65. Letter to the Secretary of the Admiralty on the Floating
Gun-Carriage (July 27, 1855) 459
66. Memorandum on Renkioi Hospital Buildings (March
1855) 463
Necessary conditions in designing these buildings (p. 463)
—General description of them (p. 463)—Closets and
lavatories (p. 464)—External and internal covering (p.
464)—Ventilation (p. 464)—Kitchens (p. 465)—Drainage
(p. 466)—Officers’ quarters (p. 466)—Transport of
materials (p. 466)—Portable baths (p. 467)—Cost of
buildings (p. 467).
67. Letter on the Direction of Railway Works (March 4, 1845) 475
68. Letter on the Position of Joint Engineer (October 16,
1843) 476
69. Letter on the Position of Consulting Engineer (December
30, 1851) 477
70. Letter on the Position of the Engineer in relation to the
Contractors (May 26, 1854) 477

71, 72, 73. Extracts from Letters on the Relations between the
478-
Engineer and the Directors (April 15, 1850; December 6,
481
1851; Jan. 22, 1857)
74, 75, 76. Extracts from Letters on Interference of Directors with the
481-
Assistant Engineers (January 19, 1842; January 28, 1842;
3
December 12, 1851)
77. Extract from Diary (May 5, 1846) 485
78. Letter to an Inventor (September 17, 1847) 486
79. Letter on the Royal Commission on the Application of
Iron to Railway Structures (March 13, 1848) 486
80. Letter on a Proposal to obtain Recognition in England of
Decorations conferred at the Paris Exhibition of 1855
(Feb. 9, 1856) 489
81. Memorandum for Evidence before the Select Committee
of the House of Lords on the Patent Laws, A.D. 1851 490
He has had large experience of the patent laws (p. 490)—
Has never taken out one, and is of opinion that the system
is productive of immense evil (p. 491)—Reasons for this
belief (p. 491)—Conditions necessary for a successful
patent (p. 493)—Disadvantages of patents (p. 494)—
Impediments in the way of improvements (p. 495).
82. Extract from Observations on the Patent Laws made by
Mr. Brunel at a Meeting of the Society of Arts (March 28,
1856) 497
83. Letter from Philæ, describing the Ascent of the Cataracts
(February 12, 1859) 517
84. Report to the Directors of the Great Western Railway
Company on the Broad Gauge, &c. (August 1838) 525
He is desirous of combining his views into one report (p.
525)—The difficulties have been overcome, or are
gradually diminishing (p. 525)—And the result justifies
the attempt which has been made (p. 526)—The gradients
of the Great Western Railway are favourable (p. 526)—
Advantages of the broad gauge (p. 527)—Reasons for
adopting it (p. 528)—Additional cost in construction is

very slight (p. 529)—Weight of carriages (p. 530)—
Freedom from accidents (p. 531)—Greater space for
works of locomotives (p. 532)—The greater width gives
scope for improvement in every part (p. 532)—Speed
obtained (p. 532)—Design of the engines (p. 533)—The
continuous system of permanent way is best adapted to
high speeds (p. 535)—Calculations as to its cost compared
with that of a well constructed line with stone blocks (p.
537).
85. Report to the Directors of the Great Western Steam-Ship
Company, recommending the Adoption of the Screw
Propeller in the ‘Great Britain’ Steam-ship (October 1840) 539
This subject will be considered under two heads: 1. The
efficiency of the screw propeller, compared with the
paddlewheel. 2. The advantages or disadvantages
attending its use (p. 539)—The first question involves the
consideration not merely of the effect produced, but also
of the proportionate power absorbed in producing that
effect (p. 539)—Observations on the slip of the
paddlewheel and screw in the ‘Great Western’ and
‘Archimedes,’ respectively (p. 540)—The result of the
comparison being, that with similar areas the screw will
meet with at least equal, if not a greater resistance, and
will consequently slip as little as or less than the ordinary
paddle-board (p. 542)—Refutation of the common error,
that the action of the screw is a very oblique one, and that
it imparts a considerable rotatory motion to the water (p.
543)—Description of the action of the screw (p. 543)—
The result of the experiments is that, as compared with the
ordinary paddlewheel of sea-going steamers, the screw is,
both as regards the effect produced and the proportionate
power required to obtain that effect, an efficient propeller
(p. 548)—Objections to the use of the screw propeller (p.
548)—Answered seriatim (p. 549)—Statement of the
principal advantages peculiar to the use of the screw (p.
552)—The result of these enquiries is a strong and

decided opinion in favour of the screw propeller being
adopted in the ‘Great Britain’ steam-ship (p. 557).

LIST

OF

ILLUSTRATIONS.

ENGRAVINGS.
Portrait (engraved with permission of Messrs. Graves and
Company by T. O. Barlow, from a portrait by J. C. Horsley,
R.A., in the possession of Mrs. Brunel) Frontispiece
PLATE to face PAGE
I. Clifton Suspension Bridge 49
II. The Hungerford Suspension Bridge 59
III. The Royal Albert Bridge at Saltash. General View. 171
IV. The Newport, Windsor, and Chepstow Bridges.
Elevations and Sections 206
V. The Royal Albert Bridge at Saltash. Elevations and
Sections. 218
WOODCUTS.
FIG. PAGE
1. Maidenhead Bridge (longitudinal section) 174
2. Bourne Viaduct (outline elevation) 181
3. Ivybridge Viaduct (the same) 182
4. Landore Viaduct (the same) 184
FIG. PAGE
5. St. Pinnock Viaduct (outline elevation, transverse
section, and plans of piers) 187
6. Experimental Girder (transverse section) 193
7. Girder on South Wales Railway (the same) 194
8. Girder on Eastern Bengal Railway (the same) 195

9. Cumberland Basin Swing Bridge (transverse section
of girder) 196
10. Windsor Bridge (transverse section of truss) 200
11. Chepstow Bridge (the same) 208
12. Saltash Bridge (the same) 219
13. Transverse Section of the ‘Great Britain’ Steam-Ship 256
14. Copy of a Sketch in a Letter on Iron Ships 259
15. Transverse Section of the Cradles and the Launching
Ways of the ‘Great Eastern’ Steam-Ship 347
16. Longitudinal Section, Plan, and Midship Section of
the ‘Great Eastern’ Steam-Ship 397
17. Monkwearmouth Dock Gates 421
18. Bristol Dock Gate 430
19. Plymouth Great Western Dock Gates 435
20. Briton Ferry Dock Gate 439
21. Brentford Dock Gate 441
22. Renkioi Hospital 470

LIFE

OF

ISAMBARD KINGDOM
BRUNEL.

CHAPTER I.

EARLY LIFE.

A.D. 1806—1828.

BIRTH OF MR. BRUNEL, APRIL 9, 1806—SIR MARC ISAMBARD
BRUNEL—THE BLOCK MACHINERY—MR. BRUNEL’S SCHOOL LIFE—
THE THAMES TUNNEL—SINKING OF THE ROTHERHITHE SHAFT—
DESCRIPTION OF THE SHIELD—EXTRACTS FROM SIR ISAMBARD
BRUNEL’S JOURNALS FROM THE COMMENCEMENT OF THE THAMES
TUNNEL TO THE DATE OF THE SECOND IRRUPTION OF THE RIVER,
JANUARY 12, 1828—NOTE A: THE BOURBON SUSPENSION BRIDGES—
NOTE B: EXPERIMENTS WITH CARBONIC ACID GAS.

Isambard Kingdom Brunel was born on the ninth day of April, 1806, at
Portsmouth, and was the only son of Sir Marc Isambard Brunel.[1]
Most biographies commence with an account of the parentage of the
person whose life is about to be written. If this be permitted in any case, no
apology can be needed for prefixing to a Life of Mr. Brunel some
particulars of his father’s career, since he was indebted to him, not only for
the inheritance of many natural gifts, and for a professional education such
as few have been able to procure, but also for a bright example of the
cultivation of those habits of forethought and perseverance, which alone can
ensure the successful accomplishment of great designs.
Sir Marc Isambard Brunel was a native of Hacqueville, a village in
Normandy, where his family had been settled for several generations. He
was originally intended for the priesthood; but, as he showed no inclination
for that calling, and a very decided talent for mechanical pursuits, he was
permitted to enter the French Navy; and he served in the West Indies for six
years, namely, from 1786 to 1792. On his return home, at the expiration of
his term of service, his strong Royalist sympathies made it unsafe for him to
remain in France, and with great difficulty he managed to escape to
America. He landed at New York in September 1793, and soon obtained
employment as a civil engineer. A few years afterwards he was appointed
engineer to the State of New York; and, while holding that office, he
designed a cannon foundry and other important public works.

In January 1799, when Sir Isambard was in his thirtieth year, he came
over to England, and shortly after his arrival married Miss Sophia
Kingdom, a lady for whom he had formed an attachment some years before.
[2]

The first great work undertaken by him in this country was the
machinery for making blocks, which he designed and erected for
Government at Portsmouth.
The history of the invention and construction of this system of
machinery (for it consisted of forty-three separate machines) need not be
given at length; but it may be permitted to extract the following passage
from Mr. Beamish’s ‘Life of Sir Isambard Brunel’ (pp. 97, 99, 2nd edition),
in which he points out the benefits which have resulted from its
introduction, and the position its inventor is entitled to hold among those
who have contributed to the progress of mechanical science.
Where fifty men were necessary to complete the shells of blocks previous to the erection of
Brunel’s machinery, four men only are now required, and to prepare the sheaves, six men can now do
the work which formerly demanded the labours of sixty. So that ten men, by the aid of this
machinery, can accomplish with uniformity, celerity, and ease, what formerly required the uncertain
labour of one hundred and ten.
When we call to mind that at the time these works were executed, mechanical engineering was
only in its infancy, we are filled with amazement at the sagacity and skill that should have so far
anticipated the progress of the age, as to leave scarcely any room, during half a century, for the
introduction of any improvement....
Beautiful as are the combinations and contrivances in the block machinery, and highly deserving
as the inventor may be of credit for originating such labour-saving machines for the production of
ships’ blocks, there is a far higher claim to the admiration and gratitude of all constructors of
machinery, and of all workers in metal. In this block machinery exist the types and examples of all
the modern self-acting tools, without the aid of which the various mechanical appliances of the
present day could not be produced with the marvellous accuracy which has been attained. It is true
that to the trades unions or combinations among the artisans, is in a great measure directly due the
introduction of self-acting machines; but the types of all these tools existed in the machines and
combinations of Brunel’s block machinery. The drilling, the slotting, and the shaping machines, the
eccentric chuck, and the slide rest, with the worm wheel motion, are all to be found in his machine.

On the completion of the block machinery Sir Isambard Brunel removed
to London, and took a house in Lindsay Row, Chelsea, where he remained
until he was obliged to live nearer the works of the Thames Tunnel.
Mr. Brunel’s first recollections were of the house at Chelsea; and in
1814, when he was eight years old, he commenced his school life under the
Rev. Weeden Butler, who resided in the neighbourhood. Previously to his
going to Mr. Butler, he had been taught Euclid by Sir Isambard; and he had

also a great talent for drawing, for which he had been remarkable even from
four years old. His drawings were beautifully precise and neat, but, when
the subject admitted of it, full of vigour and picturesque effect.
After some time he was sent to Dr. Morell’s school at Hove, near
Brighton. The following extract is taken from one of his letters home in
1820:—
I have past Sallust some time, but I am sorry to say I did not read all, as Dr. Morell wished me to
get into another class. I am at present reading Terence and Horace. I like Horace very much, but not
as much as Virgil. As to what I am about, I have been making half a dozen boats lately, till I have
worn my hands to pieces. I have also taken a plan of Hove, which is a very amusing job. I should be
much obliged to you if you would ask papa (I hope he is quite well and hearty), whether he would
lend me his long measure. It is a long eighty-foot tape; he will know what I mean. I will take care of
it, for I want to take a more exact plan, though this is pretty exact, I think. I have also been drawing a
little. I intend to take a view of all (about five) the principal houses in that great town, Hove. I have
already taken one or two.

In the intervals of his classical studies he seems to have employed
himself, not only in making a survey of Hove in its existing state, but also
in a critical examination of the works in progress for its enlargement. It is
told of him that one evening he predicted the fall, before the next morning,
of some houses which were building opposite the school, and laid a bet on
the subject, which his companions readily accepted. He had noticed the bad
way in which the work was done, and that the stormy weather, which
appeared to be setting in for the night, would probably blow the walls
down. In the morning he claimed the wager, for the buildings had fallen in
the night.
Except from November 1820 to August 1822, when he was at the
Collége Henri Quatre at Paris,[3] Mr. Brunel was so very little absent from
home that he became thoroughly acquainted with all his father’s
undertakings. Among these was the veneering machinery at Battersea,
remarkable for the great diameter of the saw, the steadiness of its motion,
and the mechanical arrangements for clearing the veneer from the saw; also
the works at the Government establishments at Woolwich and Chatham, and
the machinery for making shoes. They have been fully described by Mr.
Beamish; but the mere mention of their names is enough to show how great
were the advantages enjoyed by Mr. Brunel in receiving from his father his
early professional education.
From the year 1823 Mr. Brunel was regularly employed in his father’s
office. It was in the early part of this year that the project of the Thames

Tunnel first began to occupy Sir Isambard’s attention; but he was also
engaged at that time in other works of great importance, among them the
suspension bridges for the Ile de Bourbon, and designs for bridges of the
same character over the Serpentine, and over the Thames at Kingston.[4]
Some account of the Bourbon bridges, and also of experiments with
carbonic acid gas, on which Mr. Brunel was engaged, will be found in the
notes to this chapter.
The history of the Thames Tunnel will be told, as far as possible, in Sir
Isambard Brunel’s own words, as given in his journals.[5] Although these
extracts do not relate to works for which Mr. Brunel was personally
responsible, they have been inserted in the belief that they are valuable, not
only as showing the nature and extent of his duties as his father’s assistant,
but also as displaying, in the most interesting and authentic form, Sir
Isambard’s character and genius at a time when his son was brought into
hourly contact with him, and under circumstances which would cause the
influence of his example to make a deep and lasting impression.
Previously to the year 1823 there had been several plans suggested for
the construction of a tunnel under the Thames; and it would seem that a
great demand was supposed to exist for some such means of
communication between the two sides of the river eastward of London
Bridge; for after the failure of the operations undertaken by Mr. Vasie in
1805, and Mr. Trevethick in 1807,[6] a high level suspension bridge was
proposed, although it was not intended to be used for heavy traffic.[7]
The first reference to the Tunnel in Sir Isambard’s journals is dated
February 12, 1823. ‘Engaged on drawings connected with Tunnel;’ and on
the 17th and following days of the same month, ‘Isambard was engaged on
Tunnel.’ These entries become more and more frequent in the pages of his
diary, until it is evident that Sir Isambard’s whole time and thoughts were
absorbed in this work.
The spring of 1823 was occupied in preparing drawings and models of
his plans, and in enlisting the sympathy and assistance of various influential
persons. By the close of the year the designs were matured sufficiently to
enable the promoters of the scheme to commence the task of organising a
company for carrying it out; and in January 1824 they resolved to call a
general meeting of their friends, and invite public subscriptions.

On February 17, Sir Isambard explained his plans at the Institution of
Civil Engineers, and on the next day a meeting was held at the City of
London Tavern, under the presidency of Mr. William Smith, M.P., more
than a hundred persons being present. Resolutions authorising the formation
of a company were passed unanimously, and the share list was opened. In
the course of an hour one-third of the subscriptions was filled up, namely,
1250 shares; and before the end of the day the number of shares taken was
1381.
Borings were then commenced in order to ascertain the nature of the
strata through which the Tunnel would pass. A bed of gravel was found over
the clay, which gave Sir Isambard great anxiety. A large pipe or shaft was
sunk on the side of the river, and in it the water rose to within three feet of
the surface of the ground, and fell about eighteen inches with the tide. ‘It is
manifest (Sir Isambard writes) from this that unless the Tunnel is enclosed
in the stratum of clay, it would be unsafe to drive through the bed of gravel.
The Tunnel must, therefore, begin with the substantial clay.’
However, the result of thirty-nine borings in two parallel lines across the
river, to the depth of from 23 to 37½ feet, seemed to prove that there was
below the gravel a stratum of strong blue clay of sufficient depth to ensure
the safety of the Tunnel.[8]
A report to this effect was made to the shareholders at their first general
meeting in July, and it was also stated that the works would be completed in
three years.
The first operation connected with the works, was the constriction of a
shaft; and for this purpose land was bought on the Rotherhithe bank, about
fifty yards from the river. On March 2, 1825, the ceremony of laying the
first stone of the shaft was performed.
Mr. Smith, our chairman, attended by most of the members of the Court of Directors, and a very
numerous cortége of friends invited on the occasion, proceeded from the Tunnel Wharf to the ground,
where they were received among the cheers of a great concourse of people. Mr. Smith addressed the
assembly in a very eloquent speech suitable to the occasion, and performed the ceremony of laying
the first stone. From this day dates the beginning of the work.[9]

The mode in which Sir Isambard decided to construct the shaft was one
not uncommonly adopted in the construction of wells; but to apply it to
sinking a shaft fifty feet in diameter was a novel and bold undertaking. The
brickwork intended to form the lining of the shaft was built on the surface

of the ground, and the earth being excavated from within and underneath
the structure, it sank gradually down to its final position.
The brickwork was 3 feet thick, bound together by iron and timber ties,
and there were built into it 48 perpendicular iron rods, one inch in diameter,
fastened to a wooden curb at the bottom, and to another curb at the top of
the wall, by nuts and screws.
When the shaft or tower of brickwork was completed up to the top, 42
feet in height, the next step was to remove the blockings on which it rested,
and this being done the gravel was excavated and hoisted up, and the shaft
descended by its own weight.
The Rotherhithe shaft was only sunk forty feet in this manner; the
remaining twenty feet, in order to leave the opening for the Tunnel, was
constructed by under-pinning, or underlaying, as it was then termed. The
underlaying was commenced in the beginning of June.[10]
By July 4 they had got down to the level of the intended foundation of
the shaft, having passed into a stratum of gravel, black pebbles embedded in
greenish sand, with little or no water; from which circumstance Sir
Isambard was of opinion that it was unconnected with the stratum of gravel
above.
July 12.—Engaged on a general drawing for the great shield, and in preparing some instructions
for moving the same (a very intricate operation!)
July 22.—Underlaying is a very laborious mode of proceeding. The sinking of a wall well bound
as the first, would evidently be the best and cheapest mode for making another tower of 50 feet
diameter.

On the 28th Sir Isambard enters in his journal the following additional
observations upon the success of his plans for sinking the shaft:—
Considering the great labour necessary for securing the ground for the underlaying, the waste of
planking, and of shores, and the time necessarily taken up in moving about, in securing and in baling
out the water, and the many causes of interruption, and the imperfect way that things are done in
underlaying, it is quite conclusive that the original plan of making a shaft, by sinking the structure, is
the safest and the most economical. What is done is sound, and when once in place, may be secured
with foundations in a very easy manner. The brickwork of the shaft is remarkably hard. Had it been
made with brick facings and rubble stone, it would certainly be water-tight, and almost impenetrable
by ordinary ways. The vertical ties and the circular wall bands are not to be dispensed with in a
structure destined to be moved as the present has been.

On August 11 the underlaying was completed, and preparations were
made for constructing a reservoir in the bottom of the shaft for receiving the
permanent pumps. This was finished on October 11, with great difficulty,

owing to the nature of the ground, which consisted of loose sand containing
a large quantity of water.
August 19.—Engaged at home in revising my plans for the manner of carrying on the horizontal
excavation, more particularly of penetrating through the shaft. This part of the operation requires
indeed very great attention, as it presents great difficulties, arising from the wall to be broken
through, and chiefly from the angular opening that is to be made at each extremity. Then another
consideration is the uniting the brick arches to the brickwork of the shaft.
September 16.—Engaged in the early part of the day on revising my plans of future operations in
the Tunnel work, and in adapting them to the nature of the ground as it is found at the various depths
we have penetrated: namely, to about 73 feet. Went afterwards to Maudslay to request that the great
shield may be completed.
October 14.—Engaged in the early part of the morning in making some
arrangements for the working of the great shield. Too much attention Great shield.
cannot be given to that subject at the early part; for, when once in its place,
it would be extremely inconvenient to make any alteration.
October 15.—The dome of the reservoir will be covered to-day about
noon; the bottom of the shaft will therefore be completed. They are now Preparing for the
preparing to apply two frames of the shield. The ground now open in the frames.
front is remarkably hard; it consists of pebbles imbedded in a chalky
substance, with hard loose stones of the nature of the Kentish rag. Everything is going on well.
Devised with Isambard how to make our wells for the descent of the materials, &c.

Thus at last the shaft was completed, and Sir Isambard was able to
commence the Tunnel itself, which he ultimately determined to construct in
the form of a rectangular mass of brickwork, 37½ feet wide and 22 feet
high, pierced by two parallel horseshoe archways, each 14 feet wide and 17
feet high.
Before entering upon the history of this undertaking, some account must
be given of the machine which Sir Isambard Brunel devised for effecting its
accomplishment.
In order to avoid a quicksand of considerable depth and extent, the
Tunnel had to be carried but a short distance below the bed of the river; and,
as in all tunnelling through soft soil,[11] the top and sides of the excavation
had to be supported until the brickwork was built in; and the front or face
had also to be held up as the miners advanced. This support was given by
means of a machine called ‘the shield,’ described on one occasion by Sir
Isambard as ‘an ambulating cofferdam, travelling horizontally.’[12]
The main body of the shield consisted of twelve independent structures
or ‘frames’ made of cast and wrought iron. They were each 22 feet high,
and rather more than 3 feet wide; and, when placed side by side, like books
on a shelf, against the face of the excavation, they occupied the whole area

of the face, and also the top, bottom, and sides for 9 feet in advance of the
brickwork. Each frame stood on two feet resting on the ground, and was
divided in its height into three cells by cast-iron floors. In these cells, of
which there were thus thirty-six in all, the miners stood, and worked at the
ground in front of them.
The duty which the shield had to perform was to support the ground until
the brickwork was built within the excavation; but it was essential that this
should be done in such a manner as to allow of the mining operations being
carried on; and it was also necessary that the machine itself should be
capable of being moved forward.
The first point, therefore, which has to be explained in the action of the
shield is the manner in which the earth was supported by it.
It has been already stated that each frame rested upon two feet, or large
iron plates. These two feet together covered the ground under the frame to
which they belonged, and thus the whole of the earth beneath the frames
was pressed down by the feet.
The earth above was supported by narrow iron plates, called staves, laid
on the heads of the frames parallel to the line of the Tunnel, the ends resting
on the completed brickwork behind it. The earth at the sides was kept up by
staves resting against the outermost frames.
The arrangement for holding up the earth at the face of the excavation
was necessarily of a more complicated character. Each frame supported a
series of boards called poling-boards, by means of small screw-jacks or
poling-screws, two to each poling-board, which abutted against the frames,
and pressed the boards against the earth. The boards were 3 feet long, 6
inches wide, and 3 inches thick, and were arranged horizontally. These
poling-boards, more than five hundred in number, covered the whole
surface in front of the frames.
To resist the backward thrust of the poling-screws against the frames,
each frame was held forward by two large screws, one at the top of the
frame, and the other at the bottom, abutting against the brickwork of the
Tunnel. The brickwork was completed close up behind the shield as it
advanced.
The way in which the earth was excavated, and the shield moved
forward, has now to be explained.

The plates or staves which supported the ground at the top and sides of
the shield were pushed forward separately by screw-jacks; but in order to
advance the poling-boards in front, it was necessary that that portion of the
ground against which they pressed should be removed.
The miner, standing in his cell, took down one, or, at the most, two of the
poling-boards, commencing at the top of the cell, and having excavated the
earth a few inches in advance, replaced the poling-boards against the
newly-formed face, pressing them against it with the poling-screws. Thus
the excavation was carried on without depriving the ground of the support it
received from the shield, except at the point where the miner was actually at
work.
The operation of advancing the frames was effected in the following
way. When everything was ready for a move, one of the feet which carried
the frames on jointed legs was lifted up, and advanced forward a few
inches, and then pressed down on to the ground, until in its new position it
again bore the weight of the frame. This done, the other foot was lifted,
moved forward, and screwed down in the same manner, and then the frame
itself was pushed ahead by means of the large abutting screws, which kept it
top and bottom from being forced back on the brickwork.
It is, however, evident that these abutting screws would have been
unable to push on the frame, while the ground in front was pressing back
the poling-boards against it; therefore, during the process of moving a
frame, it had to be relieved from the thrust of its poling-screws.
Accordingly, when it was desired to advance any one of the frames, the
butts of the poling-screws of the tier of boards in front of it were shifted
sideways, so as to rest, not against the frame to which they belonged, but
against the frames next it on either side. This done, the frame itself was
advanced, and was then ready to receive again its own poling-screws, and
also those belonging to the adjoining frames, so that they might in their turn
be moved forward. It will thus be seen that the whole shield was not moved
forward at one time, but that the frames were advanced alternately.
There were many other ingenious arrangements in the design of the
shield, which need not be referred to in a description intended only to give
such a general idea of the machine as may make the history of its operation
intelligible.[13]

When the frames had been completed in Messrs. Maudslay’s factory,
they were conveyed to Rotherhithe, and lowered down the shaft. An
opening had been left at the bottom of the wall, about 37 feet wide by 22
feet high, and against this the shield was erected. It was then ready to
commence its progress through the ground below the river.
On November 25, 1825, the shield made its first start. Sir Isambard was
unfortunately unable to witness what was in fact the actual commencement
of the Tunnel, as he had three days before been seized with a sudden and
alarming attack of illness, which kept him at home till December 6. The
works were left under the direction of Mr. Brunel.
December 8.—The great shield is advancing very slowly, meeting with much interruption by the
water, which still runs within the cells, and also by the difficulty of forming abutments for the frames.
[Temporary abutments were necessary until the shield was sufficiently advanced to allow of its being
pushed forwards from the brickwork built up behind it.]
December 29.—The frames are very much out of level in the transverse line of the Tunnel. This
would be attended with serious inconvenience if I had not provided for the means of recovering any
irregularity that might take place, and which, as it appears, cannot perhaps be prevented; but having
foreseen this, I have provided the remedy by being able to take down the top of each frame, and to
remove the top staves in parts, or the whole, at pleasure—a very important provision it proves to be.
January 16, 1826.—Too much precaution cannot be taken, in the management of the frames, to
have the leg-screw particularly well secured, as every foot-run of the arch of the Tunnel sustains 82
tons. Each frame carries as follows:—

The two end frames each 65 tons = 130
Ten others, each 52½ " = 525
655 tons.

January 21.—The ground at the top and sides very good; same in the front. In breaking the
ground out of the limits of the shield on the right a great deal of ground fell in. This indicates that, if
it was not for the protection of the shield, nothing could be done. This accounts also for the
occasional breaking of the ground in making the drift in 1809.
The brickwork of the entrance being carried as far as directed, the body
of the Tunnel was begun to-day. Tunnel begun.
January 26.—Isambard went down to Rotherhithe; the water had
broken in in great abundance upon the work over Nos. 4 and 5. [The twelve
frames were distinguished by numbers.] A 4-inch pipe was driven over the Water broke into
shield from inside the shaft, but the water did not follow it, and the stream the works.
augmented very rapidly. The frame No. 5 was moved forward, and it
checked the water for a moment, but it came again with violence. A heading was immediately
ordered by Armstrong [the resident engineer] from the east well, in which Isambard concurred.
February 3.—Ordered a pit to be opened and made by sinking a curb 8 feet diameter and 18
inches thick, well bound with bolts. [This pit was a well sunk from the surface to enable the gravel

containing water, into which the head of the shield had penetrated, to be removed, and clay
substituted.]
February 6.—The shaft begun last night, and was sunk 20 feet to-day, and remarkably true. Had
we known the ground as we now know it, we might, by having opened a well contiguous to the great
shaft, have sunk the shaft in a week; but for that purpose we must have had two steam engines, one
for pumping the water, and the other for taking up the ground.
February 10.—Went very early to the Tunnel for the purpose of giving
directions to prop up the back of the staves, which, for want of weight at Unremitted
the new shaft, might be overbalanced by the pressure of the ground at the attention wanted.
back. I could not rest a moment until it was done, for the consequences
might have been fatal, at this moment in particular. What incessant attention and anxiety! To be at the
mercy of ignorance and carelessness! No work like this.
February 12.—The ground having been opened carefully from under
the curb of the pit [see above on date February 3], the greater part of the Observations on the
gravel was removed, and stiff clay substituted for it. This was done by mode adopted to
driving first some wrought-iron flat bars, which kept the ground up. This check the water.
shows that the shield is a most powerful protection, and would enable us to
penetrate through a bed of gravel. Though the breaking in of the water had somewhat terrified the
man in No. 5, he soon returned to his post, and the others have acknowledged their full confidence in
the security afforded by the shield. The boring ahead had not yet been attended to: it is owing to the
want of this precaution that this accident is chiefly to be ascribed; for had we known as much as we
now do, we might have passed through without the pit being opened.
March 1.—Water at the back of the frames, but less than before. The men show a great deal of
spirit in overcoming the present difficulties. Isambard was very busy yesterday and to-day in the
frames, and about the works. He was severely hurt in the leg by a piece of timber falling against it.
[This accident prevented his attending again at the Tunnel until the 24th.]

On March 6 the proprietors paid a visit to the Tunnel, and were highly
satisfied with what they saw. On that evening Sir Isambard writes:—
It is of absolute necessity now to provide for everything that is conducive to the more expeditious
management of the frames, and to a greater facility in getting up the brickwork. If these two points
are realized, then indeed we may soon expect to be moving at a good rate—not less than I have held
out, namely, 3 feet per 24 hours.
March 11.—Received early in the morning a report from Armstrong
stating that the water was completely stopped—that it had been stopped Water stopped as
during the night. Aware that we had passed the gravel, it was of course expected.
expected that we were under the clay; means were therefore resorted to, to
drive clay and oakum at the tail of the top staves, which was productive of a very good effect. The
great shield was soon entirely free of water. This shows the efficiency of the shield to oppose
difficulties which could not have been overcome without the complete protection it affords, under
almost any circumstances. Indeed this has been a tedious operation since January 25, when the water
first burst upon No. 5, at the front of the shield. The miners as well as the bricklayers have worked
with great spirit and perseverance through the whole, during a period of 44 days. The well that was
made at the front of the shaft has been of use in acquainting us with the extent of the open ground we
had to pass through. It will be made a useful opening for ventilating the works. By means of this well
we have been able to apply the lead pipes with which the water has been diverted: it is not therefore a
useless expense. Things were put in better order to prepare for a more expeditious way of working.

Directions were given to place the frames in a better condition. Isambard is still too unwell to go to
the Tunnel.
March 25.—Went to the Tunnel with Isambard. Found that a
considerable fall of ground had taken place again at the right side. No one Considerable slip of
could account satisfactorily for it. I inspected it, and directed that, after ground: how to
making it good, flat bars of iron be driven at the head of the side staves, in check it.
order to pin it up, and in order to enable the miners to get at the solid
ground. It is very bad and extremely dangerous; the ground is evidently the
same as that which, in the report of the first attempt, was found so loose as Very dangerous.
to have dropped upon the works, leaving a large cavity above, when it is
said the man ascended and made good the hole. We should be warned by this, lest we should meet
another as fatal as it ultimately was on that occasion. [This observation refers to the driftway of
1807.]
April 24.—By Armstrong’s report the water is entirely out, and the men at work in the morning in
removing the dirt, &c. Isambard engaged at the Tunnel, where I am not yet able to attend as often as I
could wish. Everything goes on well, much through his exertions.
May 11.—One hundred feet will be completed to-night.
May 22.—The top plate over the frame No. 1 has been cracked without any particular violence or
stress. It appears that it is nothing but the change of temperature that is the cause of that rupture. The
accident justifies the opinion I have of cast-iron not being safe upon traction, and the precaution of
having had wrought-iron bolts at the back of the frames. [These were vertical rods which took the
tensional strain.] Without these bolts what would have become of the shield, if one casting was to
break? The fracture was accompanied with a loud report like that of a gun. Isambard was in the
works at the time of breaking: nothing could have prevented it.
May 25.—I observed that nothing whatever had been gained to recover
the deviation [the shield had gradually worked 2 feet 3 inches to the The shield being
westward], which subjects us to so much inconvenience and loss of time. too much out,
The only way to bring the shield right is by taking the frames sideways. resolved to move it
June 3.—Finding it too laborious and almost fruitless to bring the bodily.
frames in the right way, I came to the determination of having them brought
bodily to the east by cutting the ground on the side. I accordingly gave directions to Armstrong to
proceed in making a heading out of No. 12, and by securing the side staves to continue downwards
until the ground be clear. The working was accordingly discontinued in front.
June 4.—The mode of proceeding by the common way of mining shows the impracticability of
carrying a large excavation anywhere, particularly under a considerable body of water. The expense
of timbering would be too great, even if it could be sound. The ground above the frames is
remarkably good, but under it there is a stratum of silt which breaks and falls in large masses.
June 5.—Isambard got into the drift, and gave the line for the better
disposition of the staves, which was afterwards done in a proper manner. Isambard’s service
Isambard’s vigilance and constant attendance were of great benefit. He is in very important and
every respect a most useful coadjutor in this undertaking. most efficient.
June 10.—The last frame (No. 1) is brought close to the others, and the
brickwork brought up to fill the back.
June 15.—On inspecting the face of the ground this morning I observed
a breach in the front of Nos. 3, 4, and 5, where the ground has given way in Dangerous state of
the lower cell. This was truly alarming. I ordered iron staves to each floor the ground.
in order to pin the ground, and thereby to counteract the slipping which Precautions taken.
would immediately take place.

June 19.—The bricklayers left off work, but, on enquiring into the cause, I learned there was no
other but to have a libation upon the new arrangement of piece-work.
June 29.—Gave positive directions to cut only 4½ to 5 inches thick at a time at the front of the
top cells, instead of 9 inches, as they had done for some time.
July 3.—The great question is, does the clay undulate at its surface? We should have some reason
to apprehend that it does so, because at the beginning we had not proceeded many feet into the clay
when we struck again into the gravelly stratum. The surface of the clay must therefore have sunk at
that particular spot; which circumstance seems to warn one of the need of great vigilance and great
prudence in the progress of the enterprise.
July 10.—A cofferdam burst yesterday at the works at Woolwich,
having blown up from the foundation. How cautious this should make our Cofferdam burst at
men! The cofferdam may be repaired, and very easily too, but an irruption Woolwich.
into the Tunnel—what a difference, particularly at this early period!
August 10.—Found the lowest cell of No. 1 left by the workmen
without a single poling against the ground. This is indeed a most Warning for us.
unjustifiable neglect.
August 12.—At six this morning completed 205 feet.
August 21.—This piece-work has not been productive of much effect as Carelessness of the
to quantity of work. As to quality it is very questionable. A work of this miners.
nature should not be hurried in this manner. Fewer hands, enough to
produce 9 feet per week, would be far better than the mode now pursued
Observations on the
from necessity, but not from inclination on my part. Great risks are in our
bad effect and
way, and we increase them by the manner the excavation is carried on. The
consequence of
frames are in a very bad condition.
driving on as is
September 5.—It is much to be regretted that such a work as the Tunnel done.
should be carried on by the piece. Obliged to drive on, no time is left to
make any repair, or to recover any lost advantage. Isambard is most active. Mr. Beamish shows much
judgment in his exertions, and zeal in his attendance.[14]
September 8.—About 2 P.M. I was informed by Munday that water was
running down over No. 9. I went immediately to it. The ground being open, Water breaking in at
and consequently unsupported, it soon became soft, and settled on the back back of frames.
of the staves, moving down in a stream of diluted silt, which is the most
dangerous substance we have to contend with. Some oakum was forced
through the joints of the staves, and the water was partly checked. Isambard How to check it.
was the whole night, till three, in the frames. At three I relieved him. He Isambard’s
went to rest for about a couple of hours; I took some rest on the stage. exertions.
September 9.—Towards noon the stream changed its character. The
clay, being loosened by the water, began to run, but it thickened gradually.
It was late in the evening before the loosened clay acquired the consistency Things improving.
of a loose puddling, which covered the staves, and made them a complete
shield against further irruption, or rather, oozings of mud. If we consider that at this place we have at
the utmost 9 feet between the top staves and the gravel, over which the river flows, it is most
satisfactory and most encouraging to have this additional proof of the protection which the shield
affords. At nine o’clock at night Isambard sent me word that ‘tout va à merveille;’ indeed it was so,
for it was like a stopper interposed between the river and the top-staves. Instructed as the men were
by the first accident, they went on as usual in the irrespective occupations. Pascoe, junr., and Collins
were remarkably active and persevering, and some other men equally so; while old Greenwell
encouraged them by a speech of his own in high commendation of the security of their situation.

September 12.—The water, bringing with it a sort of clay broken in
small particles, increased to an alarming degree. In consequence of this Water more
continued displacement of the silt and clay, a cavity had been formed above abundant. Is it from
the staves. At about three, when I had gone to the Court of Directors, the the river?
ground fell upon the staves with great violence, causing a surge most
alarming as to probable consequences. Isambard was at that moment in the upper frames, and he gave
directions for increasing the means of security. On my return I found things much worse than I left
them, but every means of security was judiciously applied. During the night in particular things
presented a very unfavourable appearance. The men, however, were as calm as if there were no other
danger to be dreaded than wet clothes or the splashing of mud. I observed the men in the lower cells
were sound asleep.
September 13.—Every means were resorted to in the course of the
night and during the early part of the day to stop the water. The men have Exertions by the
shown great zeal and good management in their respective avocations, and men.
above all the utmost confidence. Isambard has not quitted the frames but to
lay down now and then on the stage. I have prevailed on him to go to his
bed, or rather, used my endeavours to induce him; but he has not since last Slight
Friday night (the 8th). Things were rather better at the close of the day. improvement.
September 14.—Things upon the whole have assumed a more
favourable aspect. The situation is nevertheless very critical. Nothing but the utmost precaution in
following up what has begun can bring us out of it. This has been a most eventful week!
September 18.—Isambard was the greater part of the night in the works, and the benefit of his
exertions is indeed most highly felt: no one has stood out like him! Everything is quite safe, the water
is kept back, and the work proceeds in a most satisfactory manner.
October 22.—It is evident [from a flow of silt which had taken place on that day] that with the
shield we have passed close under a body of collected water a few inches only above the staves.
Isambard is too unwell to stay long in the works.
October 24.—The want of the main drain which was originally
intended to carry the water to the main reservoir is felt everywhere. This The want of a drain
drain is in my original plan, but the committee expressing on several subjects us to much
occasions a wish that I should dispense with it, I complied, most reluctantly inconvenience.
however, to prove my earnest wish to reduce the expenses. It will not, I
apprehend, be found an economy.
October 26.—Every step we take shows how much security is derived
from the shoes, supporting as they do the shield and the superincumbent Effect of the shoes
weight. They press down in the same proportion the ground on which they in keeping the
bear. They keep it as dense as it originally was, and fit it for the structure ground dense.
that is to come upon it. It is evident, therefore, that what is wanted is that
the ground should be kept pressed. It is with this object in view that I have holdfasts and jacks. What
incessant vigilance is required, what an incessant call on the resources of the mind, not only to direct,
but more particularly to provide for many things that may occur.
November 17.—At this date 307 feet 9 inches had been completed.[15]
December 8.—The evil [that of not having a proper drain] is going on with us, and without any
remedy except the drain, or a cesspool by way of expedient. How much anxiety must one feel at
being so circumstanced! Should any water break in, how should we proceed? This is another source
of great solicitude. We have no command of the frames when they rest upon wooden legs, or when
the screws are bent; and what is worse is that the men drive on without any consideration or any fear
of consequences. This circumstance, and the apprehension of the water breaking in, are matters of the
most dreadful anxiety.

December 12.—Little do others know of the anxiety and fatigue I have
to undergo day and night. Advanced as we are, we have only gained Superincumbent
somewhat more experience, but the casualties are just the same. An weight varying
accident now might be as fatal as it would have been 200 feet back, or as it daily, and still more
would be 200 feet forwards. We have not a period when we can think every fortnight.
ourselves safe except when we have connected these arches with a shaft on What stress on the
the other side. Loaded as we are with the weight of the river, we have to frames. The shoes
advance our shield and build our structure under that weight, a weight have never yielded;
which varies twice a day, and twice a month to a much greater extent. The a most important
shoes are the great foundation of our security. When once pressed down circumstance.
with the greatest power that can be applied, they do not give in the least
afterwards. They have not yielded even upon loose gravel; we must therefore congratulate ourselves
that they have answered so completely. We have now walked our frames upwards of 350 feet; we
have had to renew the legs and the heads, but it is not through want of strength so much as from
mismanagement. The first legs were never injured so long as their action was limited to 3 inches, but
when it was increased to 6 inches, they immediately gave way one after another, without however
any damage to the structure or to the shield. The heads gave way, or began to give way, from the
moment the legs did; because, when a leg gave way, it brought upon the contiguous frame an
increased weight which broke the heads one after another. That the breaking of so important a part of
our shield should not have been attended with any bad consequences is a proof that provision had
been made for the casualty. The proof that it had been foreseen and provided for is in the manner
these heads were adapted to the frames. By the way they were fixed they would be easily taken down
and replaced. Though the heads gave way, the top staves were not materially affected by it, and the
service continued until new heads were substituted. Some have fancied that the ground did not bear
wholly upon the shield and the arches, but supported itself in parts. Experience proves that the
pressure is rather more than that which rests artificially on the frames. The ground is compressed all
round by the increased weight of high water: we might therefore conclude that the shield operates as
a pillar, that supports beyond the limits of its base or cap. It is a great satisfaction to be able to say
that so long as we followed the original plan, nothing gave way except the back screws. These again
were damaged by being run out of the sockets. We may therefore ascribe most of the evils and
damages to the increased range of action, and still more to the rude implements the men have used,
whenever they met with any difficulty in moving the frames. If it is considered that we had no other
men to train in the use of this immense machine but excavators and miners, very great allowance
must be made for what has occurred.
December 20.—An accident of an alarming nature occurred. The
poling-screws of Nos. 10 and 12, being on No. 11, Moul, the miner in that Falling of three
frame, removed his butting screw; the consequence was that the frame facings from
started back, the polings and poling-screws fell down with a tremendous neglect. Awful!
crash, and the ground followed to a considerable extent. This is the most
formidable accident that has yet occurred in the face of the work. The ground was fortunately
unusually firm, and no fatal consequences ensued.
December 31.—Isambard and nine friends sat down to a dinner under the Thames! Now a year is
over since we began to make any progress horizontally, for we had only 11 feet of arch when the
water broke in on January 24 last. We may therefore say that the whole of what has been made of the
Tunnel has been made in that period. It is worthy of remark that until the end of April no fracture
whatever, no bending of the legs, had taken place, notwithstanding that we had supported for a period
of nearly three months a greater weight than we ever had since. The ground nearly 40 feet high kept
sinking upon us as we advanced, and yet no stave, no top, no leg gave way. Each leg was capable of
carrying nearly 80 tons at the point of fracture, consequently the aggregate strength of 36 legs was
equal to 2,880 tons, which is six times over the greatest effort that could be exerted by the

superincumbent weight. The heads, after they had given way, remained in place, some—namely, Nos.
1, 8, 12—for seven months, and the others from four to six months. It cannot be said therefore that
there was a want of strength, since the broken heads continued to perform for so many months after
being so much damaged; nor is there any defect in the iron. If the frames were, as some have fancied,
lanky, which implies weakness in their sides, how could they have supported the alternate stress to
which they are put by standing alternately on one leg? Not one single joint has yet started. Every
frame has been upwards of 2,000 times in that raking posture, consequently the shield has been
upwards of 24,000 times strained under the weight that has broken the heads. One single side has
broken, and is now as good as the rest. Is such a machine to be stigmatised as it has been, without
looking more minutely into its operations?
January 4, 1827.[16]—A work that requires such close attention, so
much ingenuity, and carried on day and night by the rudest hands possible Observations on the
—what anxiety, what fatigue, both of mind and body! Every morning I say, responsibility
Another day of danger over! attached to this
January 12.—It is astonishing how the silt resists the sliding of the top enterprise.
staves. Assured as we were of having stiff clay from 33 to 37 feet, with
what confidence we might have looked to making 18 feet per week. There would be no difficulty in
having accomplished it. We must not look back, but overcome all difficulties!
January 16.—Isambard having been up several successive nights, went
to bed at ten, and slept till six the next morning. I am very much concerned Isambard on duty
at his being so unmindful of his health. He may pay dear for it. several successive
February 2.—Work done to this day 405 feet 4 inches. nights.
February 3.—I visited the works; and, being in the cabin, I complained
of the dust there. Dust under the Thames!
February 26.—I went to the Tunnel. The arch being well lighted up, and the whole walk
completed, a few visitors were admitted. The coup d’œil was splendid. Mrs. Brunel, Emma, Sophia
and her three little children were the first. It gave me great pleasure to see the whole of my family in
the new scene.
March 21.—There being no clay above us, there is much to apprehend from the springs. It would
be much better to work slower than we do. It is indeed very hard to be under the necessity of driving.
Anxiety increasing daily.
March 28.—The top pumps failed; the water rose above the abutting
screws. The frames of some of them could not be advanced, nor could the No clay above
bottom brickwork be laid down—great source of complaint. Isambard head; should work
called the men in at 10 o’clock; they went on cheerfully. It is surprising that slower.
the men are so steady.
March 29.—Things are getting worse every day by the influx of water;
by which the ground is softened, and the operation rendered extremely Water increasing
complicated and slow. As to the ground, it is evident we are now as daily.
Isambard found it by his borings of August last. We have nothing above our
heads but clayey silt, and it is of a nature to be detached and run into mud
by the action of water. Our situation is
April 3.—The pumping now requires forty hands. There is no getting much worse
exaggeration in saying that the influx of water, and the badness of the daily.
ground, cause an extra expense of 150l. a week.
April 7.—It may now be said that we are contending with the elements
above and around, gaining and disputing every inch that we add to the Obstacles in every
structure.

April 9.—Isambard’s birthday, he being of age to-day. way.
April 14.—Doing as well as can be expected from the nature of the
ground, and the difficulties that increase upon us.
April 18.—The faces are found extremely tender; but having proceeded
with great caution, no accident occurred. None, I feel confident, would To be obliged to
occur if all idea of piece-work were abandoned. It always operates as a drive too fast is a
stimulant, a very dangerous one. Obliged to drive on, on account of sad alternative.
expense, we run imminent risks indeed for it. That a work of this nature,
under such circumstances, should be thus carried on, is truly lamentable. It is obvious that the clay
we have above our heads has been broken, by the ground beneath it running or breaking in upon us.
We shall have to fight it out until we have a stronger or thicker stratum of clay. Sad prospect indeed it
is for us!
April 20.—The ground at No. 1 broke in again, and occasioned great delay. Some bones and
china came down.
April 22.—The diving-bell being on the spot, and Isambard having moored it over the shield, he
and Gravatt[17] descended at thirty feet water. They found the same substances which had come
through the ground into the Tunnel. When Isambard was in the bell, he drove a strong rod into the
ground. Nelson, who was in the frame, heard the blows.
April 29.—Ground improving as we advance; we are not, however, free
from danger: a dreadful alarm took place this morning. While Isambard and A dreadful panic.
Gravatt were at breakfast, the porter came running in, and exclaiming, ‘It is
all over! The Tunnel has fallen in, and one man only has escaped.’ Gravatt was the first to get to the
spot, and found all the pumpers upon the floor of the shaft, all stupefied with horror, though every
one was there quite safe, and no rush of water was heard. Gravatt and Isambard were soon in the
shield, where they observed that a small portion of clay had fallen from the top on the top floor.
May 8.—At half-past three in the morning, an irruption took place, bringing down the deposits of
the bottom of the river—lumps of clay, stones, bones, wood, nails, &c., &c., with water. The pumpers
and men on the stage (Irish) all ran away, some exclaiming, ‘The Thames is in! The Thames is in!’
Ball and Rogers stood to their post, and soon stopped this most formidable attack.
May 10.—Great difficulties present themselves, that oppose our progress; the chief, however, is
the lodgment of water above our heads. There it loosens the silt or sand, and runs out, leaving
cavities that cause the clay above to break, and run down in lumps and disturbed streams. This is very
awful! This opens the way for the river.
May 12.—In moving No. 6, they left by some unaccountable neglect
the top staves behind, and in that state two top polings were taken down. Consequences of
The ground being very bad, and high water at the same moment, the ground want of care more
began swelling. Attention was called to several points, and Gravatt terrific and
continued in No. 6. He drew out at the front of the top staves a shovel, and mischievous than
also a hammer, that had come through the ground above. They are the same any preceding ones.
which Isambard left at the bottom of the river, when he went down in the
diving-bell.
May 13.—Notwithstanding every prudence on our part, a disaster may
still occur. May it not be when the arch is full of visitors! It is too awful to Triumph of the
think of it. I have done my part by recommending to the directors to shut shield.
the Tunnel. My solicitude is not lessened for that: I have indeed no rest, and
I may say have had none for many weeks. So far the shield has triumphed over immense obstacles,
and it will carry the Tunnel through. During the preceding night the whole of the ground over our
heads must have been in movement, and that too at high water. The shield must have therefore

supported upwards of six hundred tons: it has walked for many weeks with that weight twice a day
over its head. What flippancy and inconsistency in some individuals, who, without any knowledge of
the subject, without so much as examining the state of the work, will without the least reflection and
hesitation obtrude their suggestions upon every case. What shallow conceit for such to pretend they
can know better than those that have already the experience that must result from years of deep
thought, from days and nights of incessant attention; who have the advantage of the combined talents
of several ingenious men, who devote their undivided study, the whole resource of their well-stored
minds, to the enterprise; and to add to this, the benefit of the skill of one hundred miners and
excavators. Among this class of men, some have been employed in the most perilous enterprises,
when each individual must have acted upon his sole judgment, where, in fact, there is no room for an
engineer to instruct and direct their efforts. How easy it is to attack everything, to detract from the
merits of the best plan. There is always some weak point which may be open to the penetration of the
shallowest mind. Then comes the exulting expression, That I always said would never do, &c., and
all the consequences with it.
May 15.—The water increased very much at 9 o’clock. This is
inquiétant! My apprehensions are not groundless. I apprehend nothing, How easy to
however, as to the safety of the men, but first the visitors, and next a total detract.
invasion by the river. We must be prepared for the worst. I have had no rest
for many weeks on this apprehension. Should it occur we must make the best of it, by improving our
situation.
May 17.—There is no doubt of the ground having improved very materially since last Saturday.
Very cheering indeed.
May 18.—Visited by Lady Raffles and a numerous party. Having had an intimation by Mr.
Beamish of their intended visit, I waited to receive and to accompany them, not only from the interest
I felt at being acquainted with Lady Raffles, but also from motives of solicitude, knowing that she
intended to visit the frames. Indeed, my apprehensions were increasing daily. I had given some
instructions for enquiring where we could obtain clay, that we should have some barges full of clay to
be in readiness. I was most anxiously waiting for the removal of the tier of colliers that was over us,
being convinced that we should detect some derangement then. I attended Lady Raffles and party to
the frames, most uneasy all the while, as if I had a presentiment, not so much of the approaching
catastrophe to the extent it has occurred, but of what might result from the misbehaviour of some of
the men, as was the case when the Irish labourers ran away from the pumps and the stage. I left the
works at half-past five, leaving everything comparatively well: Mr. Beamish continued on duty.[18]
Mr. Gravatt’s account is as follows: I was above with I. Brunel looking over some prints,
Beamish being on duty. Some men came running up and said to Isambard something I did not hear.
He immediately ran towards the works, and down the men’s staircase. I ran towards it, but could not
get down. I leaped over the fence, and rushed down the visitors’ stairs, and met the men coming up,
and a lady, who I think was fainting. Met Flyn on the landing-place, who said it was all over. I
pushed on, calling him a coward, and got down as far as the visitors’ barrier. Saw Mr Beamish pulled
from it. He came on towards the shaft walking. I went up to him to ask him what was the matter. He
said it was no use resisting. The miners were all upon the staircase; Brunel and I called to them to
come back. Lane[19] was upon the stairs, and he said it was of no use to call the men back. We
stayed some time below on the stairs, looking where the water was coming in most magnificently.
We could still see the farthest light in the west arch. The water came upon us so slowly that I walked
backwards speaking to Brunel several times. Presently I saw the water pouring in from the east to the
west arch through the cross arches. I then ran and got up the stairs with Brunel and Beamish, who
were then five or six steps up. It was then we heard a tremendous burst. The cabin had burst, and all
the lights went out at once. There was a noise at the staircase, and presently the water carried away
the lower flight of stairs. Brunel looked towards the men, who were lining the staircase and galleries

of the shaft, gazing at the spectacle, and said, ‘Carry on, carry on, as fast as you can!’ Upon which
they ascended pretty fast. I went up to the top and saw the shaft filling. I looked about and saw a man
in the water like a rat. He got hold of a bar, but I afterwards saw he was quite spent. I was looking
about how to get down, when I saw Brunel descending by a rope to his assistance. I got hold of one
of the iron ties, and slid down into the water hand over hand with a small rope, and tried to make it
fast round his middle, whilst Brunel was doing the same. Having done it he called out, ‘Haul up.’ The
man was hauled up. I swam about to see where to land. The shaft was full of casks. Brunel had been
swimming too.
The first alarm, as I heard it, was as follows: Goodwin, in No. 11, said to Roger, in the next box,
‘Roger, come, help me.’ Roger said, ‘I can’t, I have my second poling down, and my face will run
in.’ In a little time Goodwin said, ‘You must come,’ which Mr. Beamish directed him to do. Roger
turned round and saw Goodwin through a sheet of water. Corps, a bricklayer, went to help Goodwin:
he was knocked down. Roger made his way alone, calling to Mr. Beamish, ‘Come away, sir, ‘tis no
use to stay.’ Roger saw Corps fairly washed out of his box like a lump of clay.

Sir Isambard’s journal continues:—
May 19.—Relieved as I have found myself, though by a terrible catastrophe, of the worst state of
anxiety, that which I have been in for several weeks past, I had a most comfortable night. Isambard
and Gravatt descended with the diving-bell, and stood upon the tails of Nos. 10, 11, and 12.
May 20.—Having descended into the hole and probed the ground, I felt that the staves were in
their places, and that the brickwork was quite sound. It is evident that the great hole has been a
dredging spot. A large mass of bags full of clay, and united together with ropes, was let down. The
Rotherhithe curate, in his sermon to-day, adverting to the accident, said it was a fatal accident, that it
was but a just judgment upon the presumptuous aspirations of mortal men, &c.! The poor man!
May 23.—Went with the diving-bell to examine the ground and the bags, which do apparently
well, but it is working rather in the dark. It cannot, however, fail of making a much better stratum
than that we had before. The plan is therefore good.

On the 30th a raft was sunk over the shield, and the water in the shaft
was brought so low that the last flight of steps was visible. However, on the
next day the river broke in again; and as it was found that the raft was open
at the west side, it was raised and towed on shore.
June 5.—There is much danger in getting out of the diving-bell, the bags are so loose in some
places. One might sink and be swallowed, which had very nearly happened to-day. Isambard and
Pinckney being down, the latter lost his hold. The footboard being accidentally carried away, he
could not have recovered himself had not Isambard stretched out his leg to his assistance.
June 17.—Visited by Charles Bonaparte. Isambard took him into the arch with the yawl.
Isambard fell overboard.[20]

On June 19, a general meeting of the proprietors was held, to consider
the position of the company. Sir Isambard addressed the meeting, and also
presented a long report, in which he entered very fully into the
circumstances of the recent accident and the causes which led to it. He then
described the means he had taken to restore the works by sinking bags of
clay and gravel. He adds: ‘I have already succeeded in closing the hole

through which the water first penetrated, and feel confident that the second
opening which afterwards appeared is also stopped, but a short time is
necessary to elapse for the new ground over the shield to settle and
consolidate. It has already supported a head of water of thirty-five feet.’

June 25.—At 7 P.M. made preparations to re-enter the shield. Isambard, mustering the men who
had been the last to quit the frames, told them they would be the first to take possession of them
again—a precedence due, as he said, to them. Rogers, Ball, Goodwin, Corps, and Compton, were
accordingly ordered to trim themselves for the expedition, provided with a phosphorus box, and
dressed in light clothes, to be fit for a swim.
At about ten o’clock, Isambard and Mr. Beamish, accompanied by Ball and Woodward (miners),
went down with the punt, and got to the large stage, the head of the crane just emerging. It was found
impossible to get into the frames, as a mound of clay and silt closed the entrance. The centering was
in place and quite sound, and of course the brickwork. Finding that they could not get nearer, they
gave three cheers, which were rapturously answered by the men at the mouth of the Tunnel. Having
placed candles upon the ground that closed the entrance, and upon the head of the crane, they
returned. Isambard, having promised that the men who had left the frames last should be the first to
re-enter, returned with them. This is a great day for our history!
June 27.—Mr. Beamish was able to get to the frames, which he found firm and undisturbed.

A small tarpaulin was now spread over the frames, and operations
commenced for cleaning them. This was a most difficult and dangerous
work, especially as the water was still so high that the frames could only be
approached by boats. The men, even the best hands, were at first greatly
alarmed at the danger they were in; but the example set by Mr. Brunel and
Mr. Beamish produced, as Sir Isambard notes, the best effect, and they soon
became reconciled to their situation.
July 7.—Very uncomfortable in the frames; the candles cannot burn, the ventilation cannot act.
Isambard went several times to-day down in the diving-bell. On one occasion the chain slipped
through the stoppers, but most providentially it jammed itself tight before being altogether run out.
The consequence might indeed have been fatal. Can there be a more anxious situation than that which
I am constantly in? Not one moment of rest either of mind or body. Mr. Beamish always ready. Poor
Isambard always at his post too, alternately below, or in the barges, and in the diving-bell.

On July 11, Sir Isambard thought that matters had so far advanced that a
large tarpaulin, which it was proposed to sink over the frames, ‘would have
its full effect.’ It was accordingly sunk on the following day, under the
superintendence of Mr. Brunel. Sir Isambard adds to his account of the
operation—‘This reflects great credit on Isambard, and the apparent facility
with which it was effected evinces his presence of mind, for a single faux
pas would have spoilt the whole.’[21]
July 21.—During the early part of the night an alarm was given, by Fitzgerald calling for clay
wedges, and exclaiming that the whole of the faces were coming in altogether. Rogers collected a
quantity of wedges to go to the frames, but no boat was to be seen. He called to the men in the
frames, but received no answer. Taking the small boat in the east arch, he reached the frames, but
found nobody, nor any appearance of derangement in the ground. Conjecturing they might be
drowned, he explored further, and saw the four men stretched on the small stage, not drowned, but
sound asleep!

July 26.—Water nearly out of the arches. For the first time we could walk to the frames—a most
gratifying circumstance indeed! Two months and eight days.
September 30.—How slow our progress must appear to others; but it is not so, if it is considered
how much we have had to do in righting the frames and in repairing them; what with timbering,
shoring, shipping and refitting—all these operations being in confined situations, the water bursting
in occasionally, and the ground running in: in short, it is truly terrific to be in the midst of this scene.
If to this we add the actual danger, magnified by the re-echoing of the pumps, and sometimes (still
more awful warning!) the report of large pieces of cast iron breaking, it is in no way an exaggeration
to say that such has been the state of things. Nevertheless, my confidence in the shield is not only
undiminished—it is, on the contrary, tried with its full effect, and it is manifest now that it will soon
replace us in good ground, and in a safe situation. No top staves have given way. That is our real
protection.
October 17.—At 2.15 A.M. Kemble, having first called upon Gravatt, came to Isambard in a
hurry, and, quite stupefied with fright, told him that the water was in. Says Isambard—‘I could not
believe him. He said it was up the shaft when he came. This being like positive, I ran without a coat
as fast as possible, giving a double knock at Gravatt’s door in my way. I saw the men on the top, and
heard them calling earnestly to those whom they fancied had not had time to escape. Nay, Miles had
already, in his zeal for the aid of others, thrown a long rope, and was swinging it about, calling to the
unfortunate sufferers to lay hold of it, encouraging and cheering those who might not find it, to swim
to one of the landings. I immediately, I should say instantly, flew down the stairs. The shaft was
completely dark. I expected at every step to splash into the water. Before I was aware of the distance
I had run, I reached the frames in the east arch, and met there Pamphillon, who told me that nothing
was the matter, but a small run in No. 1 top, where I found Huggins and the corps d’élite. They were
not even aware that any one had left the frames. The cause of the panic was one of the labourers;
hearing the man in No. 1 call for Ball, he ran away, jumping off the stage, crying, “Run, run, murder,
murder; put the lights out.” His fellow-labourers followed like sheep, making the same
vociferations.’
November 10.—Isambard gave his entertainment to nearly forty persons, who sat at table in the
Tunnel. Nothing could exceed the effect for brilliancy. About 120 men partook of a dinner in the
adjoining arch.

As the year drew to a close, the difficulty of working the silt increased,
and with this difficulty increased also the expense of maintaining the staff
of men required. On December 18, Mr. Brunel, writing for his father, who
was absent from town for a few days, thus describes the nature of the soil
through which they were then passing.
The state of the ground over Nos. 1, 2, and 3 top has caused considerable delay, particularly this
week, although not such as to give any cause of anxiety as to our future rate of progress, or to have
any serious effect except the increased expense incidental to this delay. My father desired me to
describe to the Board the causes of these difficulties. There is a considerable spring at this point, and
a corresponding soft part in the bed of the river, which seems to indicate the rising of the spring. The
ground in the neighbourhood is affected by this spring in rather a peculiar manner: at the half-flood
tide the pressure is greatest: dry hard clay oozes with great force through openings hardly observable,
the silt and water running by starts. At high-water the pressure and quantity of water begin to
diminish and on the ebb-tide the ground is hard and dry, and can be worked with ease. On the flood-
tide there are as many as twelve and fifteen of the best hands, besides myself (or one of my
assistants) and the foreman, engaged entirely at one face.

On January 1, 1828, Sir Isambard returned to London; and on the 12th,
when about 600 feet of the Tunnel had been completed, a second irruption
occurred, which put a stop to the works for seven years.
The particulars of this accident are thus described by Mr. Brunel, in a
letter to the Directors of the Company:—
I had been in the frames (shield) with the workmen throughout the whole night, having taken my
station there at ten o’clock. During the workings through the night, no symptoms of insecurity
appeared. At six o’clock this morning (the visual time for shifting the men) a fresh set or shift of the
men came on to work. We began to work the ground at the west top corner of the frame: the tide had
just then begun to flow; and finding the ground tolerably quiet, we proceeded by beginning at the top,
and had worked about a foot downwards, when on exposing the next six inches, the ground swelled
suddenly, and a large quantity burst through the opening thus made. This was followed instantly by a
large body of water. The rush was so violent as to force the man on the spot, where the burst took
place, out of the frame (or cell) on to the timber stage behind the frames. I was in the frame with the
man, but upon the rush of the water I went into the next box (or cell), in order to command a better
view of the irruption, and seeing that there was no possibility of then opposing the water, I ordered
all the men in the frames to retire. All were retiring, except the three men who were with me, and
they retreated with me. I did not leave the stage until those three were down the ladder of the frames,
when they and I proceeded about twenty feet along the west arch of the Tunnel. At this moment the
agitation of the air, by the rush of water, was such as to extinguish all the lights, and the water had
gained the height of our waists. I was at that moment giving directions to the three men, in what
manner they ought to proceed in the dark to effect their escape, when they and I were knocked down,
and covered with a part of the timber stage. I struggled under water for some time, and at length
extricated myself from the stage, and by swimming and being forced by the water, I gained the
eastern arch where I got a better footing, and was enabled by laying hold of the railway rope, to
pause a little, in the hope of encouraging the men who had been knocked down at the same time with
myself. This I endeavoured to do by calling to them. Before I reached the shaft the water had risen so
rapidly that I was out of my depth, and therefore swam to the visitors’ stairs, the stairs for the
workmen being occupied by those who had so far escaped. My knee was so injured by the timber
stage that I could scarcely swim, or get up the stairs, but the rush of the water carried me up the shaft.
The three men who had been knocked down with me were unable to extricate themselves, and I am
grieved to say, they are lost; and I believe also two old men, and one young man, in other parts of the
work.

This statement Sir Isambard embodied in a report to the Directors of
January 28, which was circulated among the proprietors.
As soon as the first excitement caused by the irruption had ceased, Mr.
Brunel directed the diving-bell to be prepared in order to ascertain the state
of the shield and the extent of the disturbance of the bed of the river caused
by the rush of water into the Tunnel.
He was, however, so seriously injured that he could not actively
superintend the preparations, but his orders were given with his usual
clearness, calmness, and decision; and as soon as the barge containing the
diving-bell was properly moored over the Tunnel, he was carried out and

laid upon a mattress on the deck of the barge, that he might direct what was
to be done.
As evening came on he became so much worse that he was taken into
the cabin; but everything which took place was reported to him.
At length, the bell being ready, it was lowered early on the Sunday
morning, but the chain not being long enough, proceedings were delayed
until a longer chain could be obtained.
As, however, a chain of the right size and length could not be obtained,
the strongest cable which could be procured in the neighbourhood was
substituted for the chain. A controversy then arose between the assistant
engineers and the foremen as to the sufficiency of the strength of the cable;
and it was agreed to consult and to abide by the opinion of Mr. Brunel, who
was then lying in great pain in the cabin.
No answer could be obtained from him for some minutes, and then he
only said, ‘Don’t go down.’ This not being satisfactory to the advocates of
the sufficiency of the cable, it was agreed to lower the bell empty, which
was done, and it was brought up safely; but just as it was swung over the
barge, the rope broke and the bell fell on to the stage.
The next day Mr. Brunel was taken home, when it was found that,
besides the injury to his knee which he received while endeavouring to save
the lives of the three men who were with him,[22] he had received serious
internal injuries, which kept him under medical treatment for several
months.
When he was able to return to Rotherhithe all hope of continuing the
works was for the time abandoned. When they were resumed, in 1835, he
was entirely engrossed in the independent pursuit of his profession; and,
with the exception of a few occasions when he acted for his father, he had
no further connection with the Tunnel.
It is not, therefore, necessary to continue the narrative in detail; but a
brief summary of the subsequent history of the enterprise may be interesting
to those who are unacquainted with it.
The Tunnel was cleared of water, and efforts were made, unfortunately
without success, to raise funds for the completion of the undertaking. Great
enthusiasm was exhibited by the general public and by many eminent
persons, including the Duke of Wellington; but the money was not

forthcoming, and nothing was left but to brick in the shield, and wait for
more favourable times.
It was not till the beginning of 1835 that the Company was able, by the
aid of a loan from Government, to recommence the works. The old shield
was removed and a new one substituted, in which considerable
improvements were introduced. Slings connecting the frames were added,
which enabled each frame to support its neighbours when necessary, and
important alterations were also made in the arrangements for keeping the
frames at the right distance from one another, and for giving greater facility
of adjustment to the various parts.
Before the Wapping side was reached there were three more irruptions of
the river, namely, August 23, November 3, 1837, and March 21, 1838; but
in October 1840 the shaft on the Wapping shore was commenced. It differed
from the Rotherhithe shaft, in being sunk the whole depth without
underpinning, and was made of a slightly conical form, to reduce the
friction in sinking, and had a larger quantity of iron hoops introduced into
the brickwork, in order to increase its strength. When this structure had
been sunk to the required depth (70 feet), the excavation of the Tunnel was
resumed, and at last the shield was brought up to the brickwork of the shaft.
The operation of making the junction between the Tunnel and the shaft was
one of much difficulty, but it was at length satisfactorily accomplished, and
the Tunnel was opened to the public on March 25, 1843—eighteen years
and twenty-three days after the commencement of the work.[23]
Sir Isambard Brunel, whose health had for some time been failing, now
retired altogether from his professional labours. After passing a few years in
peaceful and happy seclusion, surrounded by those he loved, and watched
over by their affectionate care, he died on December 12, 1849, in his 81st
year, having been spared to carry to completion his greatest work, and to
see his son following in his footsteps with a success which must have
exceeded his most sanguine expectations.

The education Mr. Brunel received from his father was well calculated to
form the foundation of his future career. During the later and more arduous
part of the contest, which was ended by the irruption of January 1828, he
held both the nominal and actual post of Resident Engineer of the Thames
Tunnel; but from the commencement of the works, when he was only

nineteen years old, he had been, as stated by Sir Isambard, ‘a most valuable
coadjutor in the undertaking.’ While placed in this responsible position he
acquired habits of endurance and of self-reliance, and learnt to act with
promptitude and decision in the application of those measures which
experience had shown to be effective in each particular class of emergency.
But beyond all other advantages, he had before him the example of his
father’s character, in which a rare degree of gentleness and modesty of
disposition was joined to unflinching energy, and a determination to
overcome all difficulties.

NOTE A (p. 5).
The Bourbon Suspension Bridges.[24]
The suspension bridges designed by Sir Isambard Brunel for crossing rivers
in the Ile de Bourbon were two in number. One of them had two spans of
122 feet each in the clear, and 131 feet 9 inches between the points of
suspension of the chains. The second had but one span of the same
dimensions as those of the larger bridge. In the design of these bridges one
of the most important points to be attended to, was to render them secure
against hurricanes, which are both frequent and severe in the Ile de
Bourbon.
In the larger bridge there was a pier of masonry, built in the middle of
the river up to the level of the roadway of the bridge. The suspension chains
of the bridge were in three groups, 9 feet 8 inches apart, so as to leave room
for two roadways, each about 8 feet 9 inches wide. Each of these groups of
chains consisted of two chains side by side. Each chain was made with long
links like those of the chain cables used for moorings.
These links, which were made of iron 1·36 inch in diameter, were 4 feet
8 inches long, inside measure, and were each connected together by two
short coupling links, 8¾ inches long, inside measure, of iron 1·36 inch by 1
inch, and two pins, each two inches in diameter.
The two chains of each group were placed side by side, with the links
upright; one of the pins at each joint was made long enough to serve for
both chains, and, in the middle of its length between the two chains, was
passed through an eye at the upper end of one of the suspending rods of the
bridge. Thus to every joint in each group of the main chains, or at intervals

of about 5 feet, there was a suspending rod. These rods were 1¼ inch in
diameter.
The pins of the joints of the main chains had half heads at each end of
them. They could thus be easily inserted in erecting the bridge, but once in
place were quite secure. At every fourth joint in the main chains one of the
joint pins was made in two halves, with wedges inserted between them for
adjusting the length of the main chains.
Thus there were six chains, and as the links of these had each two parts
of iron 1·36 inch in diameter, the total sectional area of the six chains was
17·4 inches.
Each group of the main chains was supported at a height of 25 feet 6
inches above the roadway at the centre pier, and at a height of 5 feet 3
inches at each of the side piers, the lowest portion of the curve of the chain
being about 1 foot below the points of suspension of the side piers.
The upright standards, carrying the chains both at the centre pier and at
the side piers, consisted for each group of chains of a triangular framework
of cast iron, strengthened by long bolts of wrought iron. There were thus
three of these triangular frames parallel to each other at each of the piers,
and those at the centre pier were braced together over the carriage road. The
main chains were not bolted to the standards, but were slung from them by
a vertical suspension link, which thus allowed them to move a little
lengthways. This link, in fact, performed the function of the rollers now
generally put under the saddles of suspension bridges.
The ends of the main chains were held by back stays, formed of bars 3
inches broad by 1¼ inch thick, and 10 feet long, with joints made with short
links, and 2⅜ inch pins. The ends of those back stays were secured to
holding down plates 3 feet in diameter, sunk deep in the ground and well
loaded.
As there was a vertical suspension rod at each joint of the main chains,
there was a suspension rod hanging from each of the three groups of chains
at about every five feet of the length of the bridge. To each set of these rods
was attached a cross girder of cast iron of a T section, with a large rounded
bead at the lower edge of the upright web; and connecting these under each
of the main chains was a longitudinal timber beam about 8 inches square.
The cast-iron cross girders carried longitudinal teak planking, the planks
on which the carriage wheels ran being 12 inches wide and 4 inches thick,

protected at the top by wrought-iron plates running longitudinally. The
horse-path was protected by iron plates arranged crosswise.
Under each span of the bridge were four chains curved upwards and also
sideways. These chains were fastened at their ends into the piers, and were
connected to the roadway by ties drawn up tight and attached to the main
longitudinal bearers of the platform; the object being to stiffen the platform.
These under tie chains were made each of a set of rods 1¼ inch in
diameter with eyes at their ends, the ends being connected by short joint
links and 1¼ inch pins; and to these joint links were attached the tie rods
which connect these inverted chains with the platform of the bridge, and so
prevented its being lifted or blown sideways by the force of the wind.
In the smaller bridge, which, as has been said, consisted of one span of
131 feet 9 inches between the points of suspension, these points were 15
feet 5 inches above the roadway, and the lowest part of the chain was 9 feet
7 inches below the points of suspension. The details of this bridge were
similar to those of the larger one.

NOTE B (p. 5).
Experiments with Carbonic Acid Gas.
In 1823 Mr. Faraday made the important discovery that under certain
conditions of temperature and pressure many gases could be liquefied, and
that these liquids exerted great expansive force by slight additions of
temperature, returning quickly with regularity and certainty to their original
state upon the application of cold.
The discovery of this new force appeared of such importance, that Mr.
Faraday lost no time in publishing it to the world; and Sir Isambard Brunel
very soon afterwards commenced a series of experiments to determine the
value of the liquid gas as a mechanical agent.
The first experiments were made at Chelsea; but the prosecution of them
was soon transferred to the care of Mr. Brunel at Rotherhithe, where he
devoted all his spare time to the construction of his father’s proposed
‘Differential Power Engine.’
That the progress of this discovery, and of the experiments made with a
view to the application of the liquid gas, as a motive power, may be
understood, it is necessary to state that in March 1823 Mr. Faraday

communicated to the Royal Society the results of his first experiments on
the liquefaction of gases.
The fluid was then produced by the decomposition of the hydrate of
chlorine by heat in a closed tube, the amount of gas evolved being so great
as to produce a pressure in the tube sufficient to condense the gas into a
fluid of the same volume.
This interesting experiment was followed by others with that rapidity
and success so remarkable in everything undertaken at that time in the
laboratory of the Royal Institution; and within a month another paper was
read before the Royal Society, in which the degrees of pressure and
temperature at which several gases could be liquefied were recorded, and
the means employed to produce and liquefy each gas accurately described.
On April 17 a third paper was communicated by Mr. Faraday, ‘On the
Application of Liquids produced by the Condensation of Gases as
Mechanical Agents.’
The question is thus stated: ‘The ratio of the elastic force dependent
upon pressure is to be combined with that of the expansive force dependent
on temperature; and the development of latent heat on compression and the
necessity of its reabsorption in expansion must awaken doubts as to the
economical results to be obtained by employing the steam of water under
very great pressures and very elevated temperatures.
No such doubt can arise respecting liquids, which require for their
existence even a compression equal to thirty or forty atmospheres, and
where slight elevations of temperature are sufficient to produce an immense
elastic force, and where the principal question arising is whether the effort
of mechanical motion is to be most easily produced by an increase or
diminution of heat by artificial means.’
Difficulties were suggested by Mr. Faraday as to the possibility of
obtaining sufficient strength in the apparatus, but the small difference of
temperature required to produce an elastic force of many atmospheres, he
considered would render the risk of explosion small.
To construct the machinery whereby this new force could be practically
applied as a substitute for steam, occupied the time of Sir Isambard Brunel
and his son at intervals for several years; for although Mr. Brunel was
satisfied at an early period of the enquiry that the liquefied gases could only
be advantageously employed where the cost of motive force was secondary

to economy of space and to the avoidance of the cumbrous apparatus
required for the use of steam, still he was so impressed with the importance
of the subject, if the difficulties he foresaw in its application could be
overcome, that he continued his experiments for a long period with
unflagging energy and perseverance.
The facts relating to the liquefaction of the gases, their elastic force
when liquefied under different temperatures, the rapidity with which they
could be alternately expanded and condensed, and the best mode of
producing each gas, were determined by Mr. Faraday; and as Mr. Brunel
was at that time attending the morning chemical lectures at the Royal
Institution, he was in constant communication with him, and thoroughly
conversant with his experiments.
After Mr. Brunel had made a few preliminary experiments, Sir Isambard
determined to employ liquefied carbonic acid gas for the motive power of
the proposed new engine, the facility and cheapness of its production, its
great expansive force, and its neutral character distinguishing it from any
other gas; but it was long before vessels were constructed, in which gas
could be produced in sufficient quantity and purity to exert the force
required to liquefy it in its own volume, for it was soon found to be
impossible to obtain the required pressure with pumps.
Carbonate of ammonia and sulphuric acid were the elements used, and
the generator was so arranged that it could be charged, emptied of
atmospheric air, and the joints made perfect, before the commencement of
the formation of the gas which was to be liquefied.
To the generator was attached a receiver, which could be surrounded
with a freezing mixture, so that the temperature of the gas in the cylinder
might be below that in the generator.
The gradual formation of the liquid, the development of its elastic force,
and the regularity and rapidity with which it increased or diminished by
each degree of heat or cold, were carefully watched through a glass gauge,
and the receiver when filled with liquid could be disconnected from the
generator.
The mechanical difficulties as they arose, one after the other, in the
construction and arrangement of the various parts of the generator and
receiver were at length overcome; and the receiver was not only filled with
liquid gas, but found to be capable of retaining it, whether exerting an

elastic force of 30 atmospheres at ordinary temperatures, or of 100
atmospheres when subjected to a slight degree of heat.
The receiver being satisfactorily completed, the next object of attention
was the design and construction of a working cylinder capable of resisting
at least 1,400 lbs. pressure on the square inch; a task which was one of great
anxiety, as any weakness might have caused a serious accident.
It was only after the trial of every known method of making joints to
resist high pressures had failed, that an arrangement was devised, requiring
the most perfect workmanship, by which packing of any kind was
dispensed with, and the cylinder fitted for use.
With the improved tools of the present day it is not easy to realise the
difficulties, delays, and disappointments which forty-five years ago
occurred from the failure, first of one part of a joint, and then of another;
but the construction of vessels capable of producing and also of retaining
the gas in its liquid state, with the means of alternately expanding and
condensing it from thirty or forty to eighty or one hundred atmospheres,
having been accomplished, the object of the expenditure of so much labour
and inventive power appeared to be within reach.
The construction of the machinery to utilise the elastic force contained in
the cylinder was now proceeded with. Day by day new difficulties arose,
and each as it was successfully met seemed but to leave another of greater
importance to be surmounted.
It is not necessary in this Note to describe the various arrangements
which were devised for transferring the great elastic force in the cylinder of
small diameter to a piston in another cylinder of much larger dimensions; it
is sufficient to say, that after the devotion of much valuable time extending
over several years, and a very large expenditure of money, and after
carefully considering the cost of the liquid carbonic acid gas, the difficulty
of preventing waste, and the necessarily very expensive character of the
machinery, Mr. Brunel was satisfied ‘that no sufficient advantage in the
sense of economy of fuel can be obtained by the application of liquefied
carbonic acid gas as a motive power’; but so thoroughly did he exhaust the
subject before he committed himself to this opinion, that no one has since
renewed the enquiry or attempted to make a machine to be moved by the
elastic force of liquefied gases, the construction of which, it was well
known, had baffled the inventive genius of Sir Isambard Brunel and his son.

CHAPTER II.

THE CLIFTON SUSPENSION BRIDGE.

A.D. 1829—1853. ÆTATIS 24—48.

ORIGIN OF THE UNDERTAKING—THE FIRST COMPETITION,
NOVEMBER 1829—DESCRIPTION OF MR. BRUNEL’S PLANS—MR.
TELFORD’S DECISION AS UMPIRE—MR. TELFORD’S DESIGN—THE
SECOND COMPETITION—MR. BRUNEL APPOINTED ENGINEER,
MARCH 1831—COMMENCEMENT OF THE WORKS, AUGUST 1836—
DESCRIPTION OF THE DESIGN—ABANDONMENT OF THE WORKS,
1853—FORMATION OF A NEW COMPANY AND COMPLETION OF THE
BRIDGE, 1864. NOTE: THE HUNGERFORD SUSPENSION BRIDGE.

AFTER Mr. Brunel had recovered from his accident in the Thames Tunnel,
he went for a trip to Plymouth, where he examined with great interest the
Breakwater and other engineering works in the neighbourhood. He notes in
his diary that he went to Saltash, and that he thought the river there ‘much
too wide to be worth having a bridge.’ This remark was no doubt made in
consequence of his father having some years before been consulted as to the
construction of a suspension bridge at this place, which Mr. Brunel himself,
eighteen years afterwards, selected for the crossing of the Tamar by the
Cornwall Railway, and built there the largest and most remarkable of his
bridges.
For the remainder of the year 1828, and during the greater part of 1829,
Mr. Brunel kept himself fully employed in scientific researches, and in
intercourse with Mr. Babbage, Mr. Faraday, and other friends; but he was
without any regular occupation, until, in the autumn of 1829, he heard that
designs were required for a suspension bridge over the Avon at Bristol, and
he determined to compete.
This project originated in a bequest made in 1753, by Alderman William
Vick, of the sum of 1,000l. to be placed in the hands of the Society of
Merchant Venturers of Bristol, with directions that it should accumulate at
compound interest until it reached 10,000l., when it was to be expended in
the erection of a stone bridge over the river Avon, from Clifton Down to
Leigh Down. Alderman Vick stated that he had heard and believed that the

building of such a bridge was practicable, and might be completed for less
than 10,000l.

The legacy was duly paid to the Society of Merchant Venturers, and
invested by them. The interest accumulated; and in 1829, when the fund
amounted to nearly 8,000l., a committee was appointed to consider in what
way it would be possible to carry out Alderman Vick’s intentions.
An estimate for a stone bridge was procured, but as it gave the cost at
90,000l., it was evident that this scheme must be abandoned.

The committee then advertised for designs for a suspension bridge. Mr.
Brunel, on hearing through a friend of the proposed competition, went to
Bristol; and, after examining the locality, he selected four different points
within the limits prescribed by the instructions of the committee, and made
a separate design for each of them. His plans were sent in on the day
appointed, Nov. 19, 1829, with a long statement, from which the following
description of them is taken.
The first design was for a bridge of 760 feet span between the points of
suspension, the length of the suspended floor being 720 feet. In order to
obtain a height of 215 feet above high-water mark (which was the least that
the levels allowed of), towers 70 feet high would have had to be built on the
cliffs to carry the chains. The total length of chain, including the land-ties,
was about 1,620 feet. Mr. Brunel did not approve of this design, as the
situation was not favourable to architectural effect, a point to which the
committee attached great importance; but he suggested it from its being
somewhat more economical in construction than his other plans.
In another design, the situation being some way farther down the river
than that of the design last mentioned, towers would also have been
necessary. The distance between the points of suspension was 1,180 feet,
with a suspended floor of over 900 feet. It is probable that Mr. Brunel only
proposed this plan because the site came within the limits of deviation, as
he does not say anything in favour of it in his report.
The two remaining plans are the most interesting of the series, as there
can be no doubt that, if Mr. Brunel had had his own way, he would have
adopted one of them for execution; and it appears from a little sketch on the
top of one of his earliest letters from Bristol, that his first idea for the bridge

was that which is carried out in these two designs. The site selected was one
where the rocks rise perpendicularly for a considerable height above the
proposed level of the bridge, and therefore piers and land-ties were
dispensed with, the chains being hung directly from the rock. No masonry
was required except for architectural effect.[25]

Plate I.
CLIFTON SUSPENSION BRIDGE.
Elevation of Drawing Nº 3 of Mr. Brunel’s Designs in the first competition. AD. 1829

Elevation of the Bridge according to the Design on which the works were
commenced. AD. 1836.
[Larger view]
[Largest view]

The principal difference between these two designs is that in the second
a short tunnel is avoided at one end. The style of architecture selected for
the tunnel-front and the face of the rock, as shown on the drawings sent in
to the committee, is Norman. There are also extant many beautiful sketches
made by Mr. Brunel for different parts of the design.[26]
In determining upon the mode of construction, which was the same in
the four designs, Mr. Brunel acted upon the principle which guided him in
all his subsequent undertakings, which was, as he states in his report, ‘to
make use of all that has been found good in similar works, and to avail

himself of the experience gained in them, and to combine with all their
advantages the precautions which time and experience had pointed out.’
He dismissed in a few words the plan of breaking the span into two or
three lengths. This was in his opinion unnecessary, and he computed that
the cost of a pier built up from the water’s edge to sufficient height above
the bridge to carry the chains, would be at least 10,000l. For this reason he
recommended the adoption of spans, the smallest of which far exceeded any
up to that time constructed.
In designing the chains, he dispensed with the short connecting links,
which had been previously adopted in suspension bridges, introducing
instead the method now universally used, of connecting each set of links
directly with the adjoining one by means of a pin passed through the holes
of both. The number of joints and pins was thus reduced one half, and a
considerable saving of expense, as well as diminution of weight, effected.
Another improvement, which diminished still further the weight of the
chains, was making the links in lengths of 16 feet, or nearly double that of
the longest links at the Menai bridge. The chief reason for this alteration
was to ensure a near approximation to equality in the strains on the different
links, should all the distances between the holes not be exactly equal. This
improvement was afterwards carried still further in the Hungerford
Suspension Bridge, the links of which were 24 feet long.[27]
Mr. Brunel also intended to introduce equalising beams in the supports
of the floor, so that each chain should bear an equal share of the load. By
this arrangement, there would have been comparatively few points of
suspension, and ‘the view of the scenery would not be impeded from the
observer being surrounded by a forest of suspension rods.’
The disturbance of the strains on the links arising from the greater
expansion of the metal of the outer links by the direct heat of the sun, he
proposed to obviate by sheet-iron plates placed on each side of the chains,
but separated from them by a small interval, and thus screening them from
the heat. He did not, however, use this protecting covering at the
Hungerford bridge.
All the designs show a camber or rise in the centre of the platform of the
bridge, to the extent of two or three feet; and the main chains are brought
down almost to the level of the platform. To this last arrangement, as
tending to prevent undulation, Mr. Brunel attached some importance; and

he further intended to stiffen the bridge against the action of high winds by
a system of transverse bracing, and by the addition of inverted chains,
similar to those used with success by his father in the Bourbon bridges.[28]
Such, then, were the main features of the bold and carefully matured
designs placed by Mr. Brunel before the committee. Out of twenty-two
plans submitted, only those of Mr. Brunel and four other competitors were
deemed worthy of consideration. He and his friends were naturally much
gratified at this, and were full of hope for his ultimate victory. But now,
when he seemed to have a fair chance of success in a contest which he
justly deemed would have a most important bearing upon his future
professional career, an obstacle presented itself, which for the time seemed
almost insurmountable; for he met with an unexpected opponent in Mr.
Telford, the foremost engineer of the day, and the designer of the famous
suspension bridge over the Menai Straits.
The committee of the Society of Merchants had, not unnaturally, found
themselves unable to decide upon the merits of designs for a suspension
bridge, and had asked Mr. Telford to act as their adviser in the matter.
Unfortunately for Mr. Brunel, Mr. Telford was of opinion that the maximum
span admissible was that of the Menai bridge, i.e. under 600 feet, and that
Mr. Brunel’s proposed bridge, though very pretty and ingenious, would
most certainly tumble down in a high wind.
This decision was, of course, fatal to the success of any design which
substituted one large span for two or more smaller ones, and dispensed with
pillars. Mr. Brunel therefore obtained permission to withdraw his plans
from the competition.
Mr. Telford then reported to the committee that none of the remaining
designs were suitable for adoption without the introduction of such material
alterations as would, in fact, constitute a new design. Whereupon the
committee took the only course which, under the circumstances, was open
to them, and requested Mr. Telford to prepare a design himself.
Mr. Brunel was not a little disappointed at the turn matters had taken;
but, having, as he said,‘smoked away his anger,’ he took leave of his friends
at Bristol, and went for a visit to some of the principal manufacturing towns
in the north.
Meanwhile Mr. Telford prepared his design, and it was exhibited in
Bristol in January 1830. It consisted of a suspension bridge of three spans

(the centre span 360 feet, and the side ones 180 feet each), the chains being
supported at the intermediate points by tall stone piers rising from the
river’s banks at just sufficient distance apart to avoid interfering with the
roadways on either side of the stream. The style of architecture was a florid
Gothic; and, in order to display the peculiar features of that style, the faces
of the piers were covered with elaborate panelling, and the chains
ornamented with fret-work.
This design was received with a flourish of trumpets; numerous
engravings were published, exhibiting the bridge from various points of
view, and ‘thousands of copies were disposed of;’ but, after a time, it would
appear that the captivating effect of the Gothic belfries wore off, and that
the more the citizens of Bristol looked at Mr. Telford’s plan, the less they
were satisfied with it; for, although it was deposited in the Private Bill
Office, on application being made for an Act of Parliament, the trustees who
were appointed under the Act determined to invite a second competition.
On this occasion, Mr. Telford appeared as a competitor and not as a
referee, that office being filled by Mr. Davies Gilbert, sometime President
of the Royal Society.
The site of the bridge was fixed, being that selected by Mr. Telford; but
the trustees expressly left it to the judgment of the competitors to decide
whether there should be intermediate piers or one unbroken span.
Of the thirteen designs sent in, five, including those submitted by Mr.
Telford and Mr. Brunel, were reserved for further examination. On March
17, 1831, Mr. Davies Gilbert (who had been assisted by Mr. Seward) made
his report. Mr. Telford’s design was put aside, ‘on account of the
inadequacy of the funds requisite for meeting the cost of such high and
massive towers as were essential to the plan which that distinguished
individual had proposed.’
Mr. Brunel’s design was placed second.[29] Although Mr. Gilbert
reported that it presented every desirable strength and security, he saw
objections to many of the details, and therefore did not recommend it for
adoption. However, on the following day, March 18, he stated to the
trustees that he had seen Mr. Brunel, and that it gave him much pleasure to
state that the explanations made by Mr. Brunel had materially altered his
views as to the details of the plans, which he (Mr. Gilbert) was now
satisfied were quite equal to those which he had placed first, and that,

considering the superiority of Mr. Brunel’s design in the essential particular
of strength, he should judge it preferable to any of the others.
Thereupon the trustees, ‘having considered Mr. Davies Gilbert’s report,
and referred to all the plans, including Mr. Telford’s, unanimously gave the
preference to Mr. Brunel’s,’ and appointed him their engineer.
Subscriptions came in but slowly, and it was not till 1836 that the works
were commenced.
The first stone of the abutment on the Leigh woods or Somersetshire
side of the river was laid on August 27 by the Marquis of Northampton,
President of the British Association, which was then holding its meeting in
Bristol.[30]
The span of the bridge is greater than that of Mr. Brunel’s design for the
second competition, but much less than the spans of the earlier designs, to
which he had given the preference.[31] On this point, as well as on the
question of site, he had to conform to the wishes of the trustees.[32] The
span approved of by them necessitated the building of a very large abutment
on the Leigh woods side, the height of which, from the surface of the rock
to the level of the roadway, is 110 feet. Above the roadway, the tower to
carry the chains is built to a height of 86 feet. On the Clifton side, the base
of the tower is formed by one of the boldest of the range of St. Vincent’s
rocks, which here rise almost perpendicularly to a height of 230 feet above
high water, and consequently a very small abutment was required. The
tower on this side is 3 feet higher than that on the Leigh woods side, and the
roadway has a general inclination of about 1 in 233. Mr. Brunel thought that
if the roadway were level, it would have the appearance of falling towards
Clifton, owing to the ground there being precipitous, while on the Leigh
woods side it is sloping.
He intended, in the construction of the bridge, to have followed out the
ideas embodied in his report of 1829, and would have preferred to have had
only one chain on each side of the bridge, and that much stronger than was
usually adopted; but, in deference to public opinion, he put two chains,
though he doubted if they would expand equally. ‘A rigid platform would in
some degree prevent the unequal distribution of load thus caused, but he
endeavoured to lessen the effect of unequal expansion by arranging a stirrup
at the top of each suspending rod, so as to hold equally at all times on both
chains, and thus to cause each to sustain its proportion of the load.’

The road platform was to have had beneath it ‘a complete system of
triangular bracing, which would render it very stiff.’
In order to lessen the action of wind on the bridge, he brought down the
main chains in the centre nearly to the level of the platform, and intended to
apply the system of brace chains at a small angle to check vibration. There
were, moreover, to be two curved chains lying horizontally, and attached
underneath the platform, so as to resist the lateral action of the wind.[33]
He here introduced movable saddles to carry the chains on the top of the
towers, with rollers running on perfectly flat and horizontal roller beds.[34]
By this arrangement no pressure except a vertical one could come on the
towers.
He also devised means, by levers and hydraulic presses, for relieving the
rollers and roller beds from pressure, in the event of their requiring renewal.
Mr. Brunel ultimately determined to adopt the Egyptian style of
architecture. His brother-in-law, Mr. John Callcott Horsley, R.A., gives the
following account of the proposed designs for the towers:—
‘His conception of the towers or gateways at either end of the bridge was
peculiarly grand and effective, as may be seen from his sketches still
existing. They were to be purely Egyptian; and, in his design, he had caught
the true spirit of the great remains at Philæ and Thebes. He intended to case
the towers with cast iron, and, as in perfect accordance with the Egyptian
character of his design, to decorate them with a series of figure subjects,
illustrating the whole work of constructing the bridge, with the manufacture
of the materials—beginning with quarrying the iron ore, and making the
iron, and ending with a design representing the last piece of construction
necessary for the bridge itself. The subjects would have been arranged in
tiers (divided by simple lines) from top to bottom of the towers, and in the
exact proportion of those found upon Egyptian buildings. He made very
clever sketches for some of these proposed figure subjects, just to show
what he intended by them. I remember a group of men carrying one of the
links of the chainwork, which was excellent in character. He proposed that I
should design the figure subjects, and he asked me to go down with him to
Merthyr Tydvil, and make sketches of the iron processes. We accomplished
our journey, and all the requisite drawings for the intended designs were
made.’

The works were commenced with the Leigh abutment, which was
completed in 1840, great delay having been caused by the failure of the
contractors. This misfortune led to a large excess of expenditure over the
original estimates. In 1843 the whole of the funds raised (amounting to
45,000l.) were exhausted, and there still remained to be executed the
ornamental additions to the piers (the cost of which was estimated at about
4,000l.), half of the iron work, the suspension of the chains and rods, the
construction of the flooring, and the completion of the approaches, &c., the
estimate for the execution of which was 30,000l.
Unfortunately, all efforts to raise further subscriptions were
unsuccessful; and in July 1853, when the time limited for the completion of
the bridge had expired, the works were closed in, and the undertaking
abandoned.[35]
Several proposals for completing the bridge were made in Mr. Brunel’s
lifetime, and he took every opportunity of furthering this object, which he
had very much at heart. It was not, however, till about a year after his death
that the superstructure of the bridge was actually commenced.
A company was formed in 1860 by some of the principal members of the
Institution of Civil Engineers, ‘who had an interest in the work as
completing a monument to their late friend Brunel, and at the same time
removing a slur from the engineering talent of the country.’[36] Mr. John
Hawkshaw, F.R.S., and Mr. W. H. Barlow, F.R.S., were appointed the
engineers, and Mr. Brunel’s old friend Captain Christopher Claxton, R.N.,
the secretary. The works were carried on with vigour; and the bridge was
opened with much ceremony on December 8, 1864.
The chains were brought from the Hungerford Suspension Bridge, then
in process of demolition. A description of the Hungerford bridge will be
found in the note to this chapter.[37]
Although the Clifton bridge was not completed by Mr. Brunel, his
connection with it forms a very important passage in the history of his life.
Doubtless, if he had never heard of the proposed competition in 1829, or if
he had been one of the disappointed competitors, he would have found
some other opportunity of making a name in his profession; but, as a matter
of fact, the Clifton bridge competition did give him the opportunity he
desired, and all his subsequent success was traced by him to this victory,
which he fought hard for, and gained only by persevering struggles. He

never forgot the debt he owed to Bristol, and to the friends who helped him
there; and he would have greatly rejoiced to see the completion of his
earliest and favourite work.

PLATE II

HUNGERFORD SUSPENSION BRIDGE
H. Adiard Sc.
[Larger view]
[Largest view]

NOTE (p. 58).
The Hungerford Suspension Bridge.
The suspension bridge which spanned the Thames at Charing Cross, on
the site of the present railway bridge, was designed and constructed by Mr.
Brunel between the years 1841 and 1845. It consisted of a centre span of
676 feet, and two side spans of 343 feet each. Being intended for foot
passengers only, its width was 14 feet. The versed sine, or deflection of the
middle of the catenary, was 50 feet. The two river piers, which still exist up
to the level of the railway, and form piers of the present bridge, were of
brickwork, with large footings at the bottom, so as to distribute the pressure
over a considerable area. The whole structure was made hollow and as light

as possible. From the level of the footway the piers were carried up as
ornamental campanile towers, the weight of the chains being taken by four
solid pillars of brickwork, 7 feet 3 inches square, forming the angles. Mr.
Brunel introduced here many of the arrangements he had designed for the
Clifton bridge. In order that the pressure from the chains might be always
vertical on the piers, the saddles rested on rollers working in oil, on the
level surface of a large cast-iron bed-plate. By this arrangement it was
rendered possible for the chains of the land spans to leave the tower at a
greater inclination than those of the middle span, so that the chains were
made shorter, and as they were at a lower level where they met the
abutment, there was less change in their direction at that point, and
consequently less thrust on the brickwork. Freedom of horizontal motion
was also secured, so that, in the case of unequal loading of the spans, the
chains might accommodate themselves to the strains, and move horizontally
until equilibrium was restored. At each of the land abutments the chains
passed down over a fixed saddle, at an inclination, to anchorages placed at
the bottom of the abutment. The brickwork under the fixed saddle was so
disposed as to resist directly the thrust resulting from the change of
direction between the main chains and the anchor chains. To resist any
movement of the abutments, the piles on which they rested were driven
obliquely, with their heads inclined from the river. These piles were very
numerous, the abutments spreading out so as to cover a large area at the
foundations. Nearly all the spaces between the longitudinal, cross, and
outside walls were filled with concrete, in order that the abutments might be
as massive as possible. The details of the brickwork in the piers and
abutments showed Mr. Brunel’s skill in the economical employment of this
material. The chains were constructed so that the sectional area was
proportional to the strain; the total area at the centre was 296 square inches,
while near the piers it was 312 square inches. There were four chains, two
on each side of the bridge, placed one above the other, and consisting each
alternately of ten and eleven links. The links were 24 feet long and 7 inches
in depth, the thickness varying so as to give the requisite sectional area.
The relative diameter of pin, and proper form of the ends of the link,
were subjects of much consideration, and many experiments were made in
order to determine these points. The fact that two specimens of iron,
apparently identical in every respect, sometimes exhibit considerable
difference in their breaking weights, shows that an average of a great

number of experiments is required in order to test satisfactorily any
proposed refinements of construction. Mr. Brunel, however, convinced
himself by experiment that he had practically arrived at such a form of link
and diameter of pin that the chain would have no tendency to break at one
point rather than another. The links were forged with shoulders near the
eyes, in order that by means of clamps the pin could be taken out and the
links disengaged, if necessary.
The efficient action of the rollers was demonstrated shortly after the
completion of the bridge. On the occasion of the opening of the Corn
Exchange by Prince Albert, one of the land spans was crowded with people,
while the centre span was nearly empty. In consequence of this the land
chains became depressed considerably below their normal position; and the
saddles on the top of the tower nearest to the loaded span moved
horizontally on the rollers to the extent of 3 inches; and, when the crowd
had dispersed, they returned to their original position.
Many years after the completion of the bridge a proposal was made to
widen it for carriage traffic; but this was not carried out, and eventually the
superstructure was removed, to make way for the bridge of the Charing
Cross Railway. As the Hungerford Suspension Bridge has ceased to exist,
an engraving has been given of it (Plate II. p. 59), in order that some record
of its appearance may remain.

CHAPTER III.

EARLY HISTORY OF THE GREAT WESTERN RAILWAY.

A.D. 1833—1835. ÆTATIS 27—30.

SKETCH OF THE HISTORY OF RAILWAYS IN ENGLAND PRIOR TO 1833
—THE STOCKTON AND DARLINGTON—THE LIVERPOOL AND
MANCHESTER—THE LONDON AND BIRMINGHAM—PROPOSED
RAILWAY BETWEEN LONDON AND BRISTOL—MR. BRUNEL
APPOINTED ENGINEER, MARCH 7, 1833—SURVEY OF THE LINE—
UNSUCCESSFUL APPLICATION TO PARLIAMENT IN 1834—
SUCCESSFUL APPLICATION IN 1835—REMINISCENCES OF MR.
BRUNEL, 1833-1835—EXTRACT FROM MR. BRUNEL’S DIARY,
WRITTEN AT THE CLOSE OF 1835.

BEFORE entering upon the history of the Great Western and the other
railways of which Mr. Brunel was the engineer, it may be useful to give a
brief sketch of the development of the railway system, previous to the
period when he first became engaged in works of this description.
The first railway in England designed for the conveyance of general
merchandise and passengers, was the Stockton and Darlington. An Act of
Parliament authorising the construction of this line was passed in 1821.
In 1823, a further Act was obtained, in which a clause was inserted, at
the request of Mr. George Stephenson, then the engineer of the company,
taking power to work the railway by locomotive engines, and to employ
them for the haulage of passengers. This railway, which consisted of a
single line with four sidings in the mile, was opened for traffic on
September 27, 1825. Its success led at once to the promotion of similar
works in other parts of the country.
Next in order must be noticed the celebrated railway between Liverpool
and Manchester. A project for constructing a line of railway between these
important towns was discussed as early as the year 1822; but a company for
carrying it out was not formed till two years later. In 1825, the directors
applied to Parliament for an Act; and after a long contest before a
committee of the House of Commons, the preamble approving of the
construction of the railway was carried by a majority of one. The Bill was,

however, withdrawn, as the first two clauses empowering the company to
make the line, and to acquire land for that purpose, were lost.[38] In the
following year the Act was obtained, and the works were commenced under
the direction of Mr. George Stephenson. The line was opened for traffic on
September 15, 1830.
In 1824, Mr. George Stephenson wrote a report on a proposed line
connecting Liverpool and Birmingham. Surveys were made, and plans
deposited; but the Bill was thrown out on standing orders. A similar fate
attended the introduction of a Bill in 1826. In 1830, a new line was
surveyed by Mr. Joseph Locke and Mr. Rastrick, under the direction of Mr.
George Stephenson. The Act was obtained in 1833, and the railway, which
was called the Grand Junction, and is now a part of the London and North-
Western system, was constructed by Mr. Locke.[39]
In 1830, surveys were commenced by Mr. Robert Stephenson for a line
between London and Birmingham, and a Bill was introduced into
Parliament in 1832. The Liverpool and Manchester Railway had now been
opened for some time, and the promoters of the Birmingham line had the
advantage of being able to give in evidence the results of the working of the
earlier undertaking. Those results, it is said, were such as to startle most of
those who heard them. It was shown that a speed had been attained double
that of the fastest stage-coach, that the cost of travelling had been
diminished by one half, and that out of 700,000 persons carried since the
opening of the railway, only one had met with a fatal accident. The amount
of travelling between Liverpool and Manchester had increased four-fold,
and the value of the shares of the railway had risen one hundred per cent.
Similar evidence was given as to the results of the working of the Stockton
and Darlington Railway, and the promoters endeavoured to prove that
advantages at least as great would arise from the construction of a railway
between Birmingham and London. They were successful in the House of
Commons; but, they failed to convince the Upper House that the benefits
which such a railway would confer on the country traversed by it were
sufficient to entitle its promoters to receive for it the sanction of the
legislature. The Bill was again introduced in the following session (1833);
and, strange to relate, it passed both Houses almost without opposition.[40]

Meanwhile, the principal merchants of Bristol, who had in 1825 made an
attempt to get up a railway company, were urged forward, both by the
inadequacy of their communications with the metropolis, and by the success
of the Liverpool and Manchester Railway, to make another effort. In the
autumn of 1832 a committee was formed of members of the corporation,
and other public bodies of the city of Bristol, to carry out the project of a
railway to London.
The first step taken by the committee was the appointment of an
engineer to make the preliminary surveys, and to prepare an estimate of the
cost of the undertaking.
Among the candidates for the post was Mr. Brunel. He was well known
in Bristol as the engineer of the Clifton Suspension Bridge, and of the
works for the improvement of the Floating Harbour. He had made many
friends among the leading citizens, and they used their best exertions to
procure his election; but there were several other candidates in the field
who had great local interest, and the contest was a close one.
While the issue was yet undecided, an unexpected difficulty arose. Some
members of the committee resolved to select their engineer by means of a
competition among the candidates, as to which of them would provide the
lowest estimate. Upon this being announced, Mr. Brunel declared that he
must withdraw his name, as he could not consent to become a party to so
objectionable a proceeding. ‘You are holding out,’ he wrote to the
committee, ‘a premium to the man who will make you the most flattering
promises. It is quite obvious that the man who has either least reputation at
stake, or who has most to gain by temporary success, and least to lose by
the consequences of disappointment, must be the winner in such a race.’
Happily, this plan was abandoned; Mr. Brunel obtained a majority of votes,
and was appointed engineer on March 7, 1833.
He commenced the survey without delay; and in addition to his strictly
professional duties, he assisted in forming a committee in London, and took
a leading part in the consultations which were held upon various important
matters connected with the general interests of the undertaking.
A hasty survey of the country between London and Bristol occupied him
till the middle of June; and as soon as it was completed, and the course of
the line settled on, preparations were made for placing the scheme before
the public.

The first public meeting was held on July 30, 1833. Mr. Brunel thus
refers to it in his diary:—‘Got through it very tolerably, which I consider
great things. I hate public meetings: it is playing with a tiger, and all you
can hope is, that you may not get scratched, or worse.’ The result, however,
seems to have been successful, and in a month’s time a company was
formally constituted, and the parliamentary survey commenced.
Mr. Brunel organised a staff of assistants, at that time rather a difficult
task, and set them to work on various parts of the line. His own duty of
superintendence severely taxed his great powers of work. He spent several
weeks travelling from place to place by night, and riding about the country
by day, directing his assistants, and endeavouring, very frequently without
success, to conciliate the landowners on whose property he proposed to
trespass.
His diary of this date shows that when he halted at an inn for the night,
but little time was spent in rest, and that often he sat up writing letters and
reports until it was almost time for his horse to come round to take him on
the day’s work. ‘Between ourselves,’ he wrote to Mr. Hammond, his
assistant, ‘it is harder work than I like. I am rarely much under twenty hours
a day at it.’
A great portion of this labour was for the time thrown away, for as
November 30 drew near, it became evident that subscriptions were not
coming in to the extent which would enable the directors to lodge a Bill for
the whole line in the session of 1834.
The directors therefore determined to apply to Parliament for powers to
make a railway from London to Reading, and from Bath to Bristol, ‘as a
means of facilitating the ultimate establishment of a railway between
London and Bristol;’ postponing till a future session their application for an
Act to enable them to complete the undertaking by making the line from
Reading to Bath.
The Bill was introduced into the House of Commons, and on March 10,
Lord Granville Somerset moved that it be read a second time. This motion
was seconded by the Earl of Kerry, and supported by several influential
members, amongst whom were Mr. Labouchere (the late Lord Taunton) and
Mr. Daniel O’Connell.
The second reading was carried by a majority of ninety in a House of
274 members.

The Bill was then referred to a committee which met on April 16, Lord
Granville Somerset being in the chair. Evidence was called to prove the
advantages of the railway to the agricultural and trading community of the
country through which it would pass, even if only the two proposed
divisions of the line were constructed.
The traffic in merchandise between Bristol and London was at this time
principally carried on by means of water carriage, consisting, first of the
river Avon navigation from Bristol to Bath, next of the Kennet and Avon
Canal from Bath to Reading, and lastly of the river Thames from Reading to
London. The evidence went to show that the distance between London and
Reading, which by railway would be thirty-six miles, amounted by the river
to nearly eighty; that the delays and impediments arising from drought,
flood, and frosts on the rivers, were such as sometimes to detain barges for
several weeks; and that so great were the consequent uncertainties and
inconveniences of this navigation, that goods which came as far as Reading
by the canal, were frequently sent thence to London by road, although at a
great increase of expense. Even under the most advantageous
circumstances, goods could not be conveyed from Reading to London in
less than three days, or in less than a day by the river Avon from Bath to
Bristol. It was therefore contended, that to form a railway which should
supersede, or at all events come in aid of, the worst portions of the
navigation between London and Bristol, would be an important public
benefit.[41] The various advantages of the measure were most fully
discussed in an investigation which lasted during fifty-seven days. Against
the Bill was arrayed every class of opponent that a private Bill could
possibly encounter. Those interested in the canals, rivers, and stage-
coaches, opposed it from the fear of competition; the inhabitants of Windsor
opposed it, because the railway did not run so near to the town as they
wished; the corporation of Maidenhead opposed it, because they thought
that all the traffic which paid toll on their bridge over the Thames would be
diverted to the railway; landowners and farmers near town opposed it,
because they feared it would bring produce to London from a distance, as
cheap as that supplied by themselves.
There was another very formidable class of opponents to the Bill,
consisting of landed proprietors and owners of houses in the immediate
neighbourhood of London.

Many engineers were called by these several opponents, to show that a
more advantageous line of railway might have been selected; but, upon
sifting the merits of the various new lines proposed, it became apparent that
the one chosen by Mr. Brunel was the best. Indeed, although some trifling
deviations of his line were suggested, the opposing engineers admitted that
in all essential features the railway had been most skilfully laid out. It was
generally agreed that the line through the valley of the Thames, and thence
in a direction north of the Marlborough Downs, was the only proper course
for a railway between Bristol and London, as the levels were much better,
and communication could be made with much greater ease with the
northern and South Wales districts, than if the route to the south of the
Marlborough Downs had been selected.
The plans proposed for entering London raised great opposition. In this
respect public feeling has greatly changed, for now no railway is thought
complete which has not a terminus in the heart of London; and it is
considered an advantage for houses to be within easy reach of a railway
station; but in 1834 such a neighbour was looked upon with horror and
dismay—a nuisance to be, if possible, absolutely prohibited.
When Mr. Brunel commenced the survey for the London terminus, he
had some idea of bringing the railway in on the south side of the Thames;
but this was abandoned, as it was found to involve very heavy works, and
the line proposed in the first Bill was made to terminate on the north side of
the river at Vauxhall Bridge. It was to have been carried on a viaduct 24 feet
high, with a parapet 6 feet 6 inches high, to prevent the passengers looking
into the windows of the neighbouring houses.
The owners of the land through which this part of the line would pass
were influential members of the Upper House, and therefore the directors
thought it useless to brave their opposition; accordingly, on the thirteenth
day of the hearing, they abandoned the last two miles of the viaduct, and
proposed to stop at the ‘Hoop and Toy,’ a public-house near the site of the
South Kensington Station of the Metropolitan Railway.
But although the opposition of some of the landowners was conciliated
by this concession, that portion of the line through Brompton which had not
been abandoned was attacked with unabated energy. The residents in
Brompton opposed the Bill from the apprehension that the railway would
interfere with their quiet and seclusion; Brompton being at that time

considered, at any rate by one of the counsel for the opposition, ‘the most
famous of any place in the neighbourhood of London for the salubrity of its
air, and calculated for retired residences.’ They could not, indeed, be
blamed for indulging in these apprehensions, if they really believed in their
counsel’s statement that ‘streams of fire would proceed from the locomotive
engines.’
Others objected to the viaduct itself as being an undertaking of so
colossal a nature as hardly to be practicable; and the supposed increase of
traffic and consequent obstruction in Piccadilly and other leading
thoroughfares brought down upon the promoters the opposition of the
Commissioners of Metropolitan Roads.
All these objections were made the ground of much argument in
committee, and doubtless had great influence over the minds of those who
voted against the Bill.
The engineering evidence occupied, as might be expected, the greater
part of the forty-two days during which witnesses were examined before the
committee, and of these forty-two days no less than eleven were taken up
by the cross-examination of Mr. Brunel. So protracted a cross-examination
has probably never been heard in any court or committee-room. One of
those present thus describes it:—
‘The committee-room was crowded with landowners and others
interested in the success or defeat of the Bill, and eager to hear Brunel’s
evidence. His knowledge of the country surveyed by him was marvellously
great, and the explanations he gave of his plans, and the answers he
returned to questions suggested by Dr. Lardner, showed a profound
acquaintance with the principles of mechanics. He was rapid in thought,
clear in his language, and never said too much, or lost his presence of mind.
I do not remember ever having enjoyed so great an intellectual treat as that
of listening to Brunel’s examination, and I was told at the time that George
Stephenson and many others were much struck by the ability and
knowledge shown by him.’
In his evidence, Mr. George Stephenson stated that he did not know any
existing line so good as that proposed by Mr. Brunel. ‘I can imagine (he
said) a better line, but I do not know of one so good.’[42]
At length, on the fifty-fourth day of the sittings of the committee, Mr.
Harrison, K.C., rose to reply on behalf of the promoters, and on the

conclusion of his address the Bill was passed.
In the House of Lords the second reading was moved by Lord
Wharncliffe. It was opposed, and on a division being taken, the motion was
lost by a majority of seventeen (30 content and 47 non-content). The Bill
was therefore thrown out.
The directors, undaunted by their defeat, lost no time in making
preparations for bringing a Bill before Parliament in the session of 1835,
with such improvements as the experience of the past campaign suggested
to them. Taking into consideration the various grounds on which opposition
had been raised to the plans they had proposed for entering London through
the Brompton district, they opened negotiations with the London and
Birmingham Railway Company, and arrangements were concluded by
which the traffic of the Great Western Railway was to be carried upon the
London and Birmingham line for the first four miles out of London, the
junction being made a little to the west of the Kensal Green Cemetery.
They had also during the autumn raised money enough to enable them to
apply to Parliament for powers to construct the whole of the line from
London to Bristol. They thus escaped all the sarcastic observations which
had been made upon the scheme of 1834, of which it had been said, that it
would be a head and a tail without a body, and neither ‘Great’ nor
‘Western,’ nor even a ‘railway’ at all, but ‘a gross deception, a trick, and a
fraud upon the public, in name, in title, and in substance!’
On March 9, the earliest day allowed by the standing orders, the Bill was
read a second time and committed. A division being taken on the motion for
committal, there appeared in favour of the motion 160, and against it none
but the tellers.
Shortly after its first meeting, the committee, of which Mr. Charles
Russell, then member for Reading, was chairman, came to the resolution
that, inasmuch as the evidence given in the previous year as to the public
advantages of a Bristol railway had been referred to them by order of the
House, they needed no further evidence on that subject. Counsel were
therefore directed to confine their case as much as possible to the merits of
the line proposed.
Evidence was called by the opponents chiefly with a view to show the
advantages of a proposed line from Basing to Bath, and the inexpediency of
granting an entirely new line of 115 miles in length to the Great Western

Railway Company, which involved the construction of a ‘monstrous and
extraordinary,’ ‘most dangerous and impracticable, tunnel’ at Box, and this,
when 44 miles of railway in a western direction—viz. as far as Basingstoke,
had already been sanctioned by the legislature in the Southampton Railway
Act, passed in the previous session. The promoters of the Bill contended
that the levels of the Basing and Bath line were not so good as those
proposed for their own, and that the Great Western Railway would approach
almost every town of importance situated on the proposed Basing and Bath
line, by means of short branches; whilst at the same time it presented the
great advantage of being capable of easy extension to Gloucester and
Wales, and to Oxford, an object wholly unattainable by the other line. In
reply to these assertions, the opponents maintained that although the levels
of the Basing and Bath Railway presented greater inclinations than those of
the Great Western, yet that they were so balanced as that the rises and falls
compensated one for another, so as to render the line practically level. The
enunciation of this theory called forth a remark by the chairman that
according to this principle the Highlands of Scotland would be as good as
any other place for the construction of a railway.
The preamble was voted proved, and the Bill passed the House of
Commons without further opposition, and on May 27 was read a first time
in the Lords. On June 10, the second reading was carried after a sharp
debate, the numbers being 46 contents, and 34 non-contents.
Lord Wharncliffe was chairman of the committee.[43] The proceedings
began by an opposition on the standing orders, which, after much
skirmishing, were voted to have been complied with. The promoters,
however, judged from the nature of the first day’s proceedings, that they
had to expect a contest of no inconsiderable duration; and the result proved
their anticipations to have been correct. For forty days the battle was fought
with a degree of earnestness and vigour on both sides, almost unequalled in
any similar proceedings.
The committee soon came to the same decision as the House of
Commons, that, with regard to the advisability of a Bristol railway, they
were satisfied, and needed no further evidence. The case became then one
of mere comparison between the relative merits of the two lines proposed.
The case in support of the Bill occupied eighteen days, and was closed
with a speech by the Hon. John Talbot.

Mr. Serjeant Merewether, whom the opponents had chosen as their
leader in the House of Lords, was then heard on their behalf, and occupied
no less than four days in the delivery of his speech, in which certainly no
argument that ingenuity could devise was omitted to strengthen his case.
There was hardly any conceivable injury which, according to the learned
serjeant’s notions, the Great Western Railway would not inflict. It was said
that the Thames would be choked up for want of traffic, the drainage of the
country destroyed, and Windsor Castle left unsupplied with water. As for
Eton College it would be absolutely and entirely ruined: London would
pour forth the most abandoned of its inhabitants to come down by the
railway and pollute the minds of the scholars, whilst the boys themselves
would take advantage of the short interval of their play hours to run up to
town, mix in all the dissipation of London life, and return before their
absence could be discovered. Moreover, while the beauty of the country and
the retirement of private dwellings would be destroyed, the interests of the
public would be far more effectually served by the adoption of the Basing
and Bath line, and a line from the London and Birmingham Railway to
Gloucester. This was in fact the point at issue, and on this the result of the
contest depended. The promoters of the Bill had called, in support of their
line, in addition to Mr. Brunel, who being engineer to the company might
be considered an interested witness, Mr. Locke, Mr. Palmer, Mr. Price, Mr.
George Stephenson, and Mr. Vignoles. They expressed their unqualified
approbation of the line chosen by Mr. Brunel, and of the estimates he had
prepared.
The preamble was proved, and after an unsuccessful opposition the Bill
was read a third time, on August 27. The Royal Assent was given on the last
day of that month.[44]

During this contest Mr. Brunel made among his fellow-labourers many
deep and lasting friendships. One of the most intimate of these friends, Mr.
St. George Burke, Q.C., has, in compliance with a request made to him,
furnished the following reminiscences of his intercourse with Mr. Brunel
during the progress of the Bill through Parliament.
March 9, 1869.
‘My dear Isambard,—You wish me to supply you with reminiscences of my old associations with
your father, in order that, in your biography of him, you may present a true picture of those features
of his character which so endeared him to his most intimate friends.

‘For many years it was my good fortune to enjoy his friendship, and many of the pleasantest
hours of my life were due to it.
‘For a period of nearly three years, viz. during the contest for the Great Western Railway Bill, I
think that seldom a day passed without our meeting, whether for purposes of business or pleasure,
both of which his buoyant spirits enabled him to combine in a manner which I have seldom seen
equalled.
‘It would be wearisome to detail the many incidents which occurred illustrative of the singularly
facile manner in which, in the midst of the heaviest and most responsible labours, he could enter into
the most boyish pranks and fun, without in the least distracting his attention from the matter of
business in which he was engaged; but all who knew him as I did could bear testimony to this
characteristic of his disposition.
‘I believe that a more joyous nature, combined with the highest intellectual faculties, was never
created, and I love to think of him in the character of the ever gay and kind-hearted friend of my
early years, rather than in the more serious professional aspect under which your pages will, no
doubt, rightly depict him.
‘In 1833 your father and I occupied chambers facing each other in Parliament Street, and as my
duties involved the superintendence, as Parliamentary agent, of the compliance with all the Standing
Orders of Parliament, and very frequent interviews and negotiations with the landowners on the line,
we were of necessity constantly thrown together. To facilitate our intercourse, it occurred to your
father to carry a string across Parliament Street, from his chambers to mine, to be there connected
with a bell, by which he could either call me to the window to receive his telegraphic signals, or,
more frequently, to wake me up in the morning when we had occasion to go into the country
together, which, it is needless to observe, was of frequent occurrence; and great was the astonishment
of the neighbours at this device, the object of which they were unable to comprehend.
‘I believe that at that time he scarcely ever went to bed, though I never remember to have seen
him tired or out of spirits. He was a very constant smoker, and would take his nap in an arm-chair,
very frequently with a cigar in his mouth; and if we were to start out of town at five or six o’clock in
the morning, it was his frequent practice to rouse me out of bed about three, by means of the bell,
when I would invariably find him up and dressed, and in great glee at the fun of having curtailed my
slumbers by two or three hours more than necessary.
‘No one would have supposed that during the night he had been poring over plans and estimates,
and engrossed in serious labours, which to most men would have proved destructive of their energies
during the following day; but I never saw him otherwise than full of gaiety, and apparently as ready
for work as though he had been sleeping through the night.
‘In those days we had not the advantage of railways, and were obliged to adopt the slower,
though perhaps not less agreeable, mode of travelling with post-horses. Your father had a britzska, so
arranged as to carry his plans and engineering instruments, besides some creature comforts, never
forgetting the inevitable cigar-case among them; and we would start by daybreak, or sometimes
earlier, on our country excursions, which still live in my remembrance as some of the pleasantest I
have ever enjoyed; though I think I may safely say that, pleasurable as they were, we never lost sight
of the business in which we were engaged, and for which our excursions were undertaken.
‘I have never known a man who, possessing courage which to many would appear almost like
rashness, was less disposed to trust to chance or to throw away any opportunity of attaining his object
than was your father. I doubt not that this quality will be fully exemplified in the details which you
will have received of his engineering experiments; but I speak of him also in the character of a
diplomatist, in which he was as wary and cautious as any man I ever knew.
‘We canvassed many landowners together, and I had plenty of opportunities of judging of his
skill and caution in our discussions with them, though we had many a good laugh afterwards at the
arguments which had been addressed to us as to the inutility and impolicy of the scheme in which we

were engaged, and the utter ruin it would be sure to entail on its promoters, as well as on the country
affected by it.
‘I frequently accompanied him to the west of England, and into Gloucestershire and South Wales,
when public meetings were held in support of the measures in which he was engaged, and I had
occasion to observe the enormous popularity which he everywhere enjoyed. The moment he rose to
address a meeting he was received with loud cheers, and he never failed to elicit applause at the end
of his address, which was distinguished as much by simplicity of language and modesty of pretension
as by accurate knowledge of his subject.
Yours very truly,
St. George Burke.
Isambard Brunel, Esq.’

The following is an extract from Mr. Brunel’s diary, written at the end of
the year 1835:—
53 Parliament Street, December 26.
What a blank in my journal [the last entry is dated January 1834], and during the most eventful
part of my life. When last I wrote in this book I was just emerging from obscurity. I had been toiling
most unprofitably at numerous things, unprofitably, at least, at the moment. The railway was
certainly being thought of, but still very uncertain. What a change. The railway now is in progress. I
am thus engineer to the finest work in England. A handsome salary, on excellent terms with my
directors, and all going smoothly. But what a fight we have had, and how near defeat, and what a
ruinous defeat it would have been. It is like looking back upon a fearful pass; but we have succeeded.
And it is not this alone, but everything I have been engaged in has been successful. Clifton bridge
—my first child, my darling, is actually going on: recommenced work last Monday—glorious!!
[Here follows a list of the undertakings on which he was then engaged.] I think this forms a pretty list
of real sound professional work, unsought for on my part, that is, given to me fairly by the respective
parties—all, except the Wear Docks, resulting from the Clifton bridge, which I fought hard for, and
gained only by persevering struggles.... And this at the age of twenty-nine. I really can hardly believe
it, when I think of it. I am just leaving 53 Parliament Street, where I may say I have made my
fortune, or, rather, the foundation of it, and I have taken 18 Duke Street.

CHAPTER IV.

RAILWAY WORKS.

A.D. 1835—1859. ÆTATIS 30—54.

CONSTRUCTION OF THE GREAT WESTERN RAILWAY—THE BOX
TUNNEL—THE BATH AND BRISTOL STATIONS—THE PADDINGTON
STATION—THE GREAT WESTERN HOTEL—BRANCHES AND
EXTENSIONS OF THE GREAT WESTERN RAILWAY—THE BRISTOL
AND EXETER RAILWAY—RAILWAYS IN DEVONSHIRE AND
CORNWALL—RAILWAYS TO BASINGSTOKE, TO WEYMOUTH, AND TO
SALISBURY—IN SOUTH WALES—IN IRELAND—IN ITALY—IN INDIA
—SUPERVISION OF WORKS—MR. BRUNEL’S ENGINEERING STAFF—
HIS REPUTATION AS A WITNESS—REMINISCENCES OF MR. BRUNEL,
1835-1838.

IN the extract from Mr. Brunel’s diary given at the close of the last chapter
he refers to the successful issue of the contest for the Great Western
Railway Act as a very important event in his life.
As the result proved, he did not take too hopeful a view of his future
prospects; for from that time to his death he was fully employed as the
engineer of railways which, in number and importance, were not inferior to
those of any of his contemporaries. Of the main lines he constructed, one
extends uninterruptedly from London to the Land’s End, and another to the
extremity of South Wales, at Milford Haven, 285 miles from Paddington.

It would be impossible to describe in detail all the engineering works
which are to be found on Mr. Brunel’s railways, the aggregate length of
which is upwards of 1,200 miles; but in this chapter it is proposed to give a
brief sketch of the lines he constructed, omitting all that can be more
properly inserted in the three chapters which follow, relating to the broad
gauge, to the Atmospheric System, and to the bridges and viaducts.

The Great Western Railway was opened to Maidenhead, a distance of
nearly twenty-three miles, in June 1838, and to Twyford, eight miles farther

on, in July 1839. A description of the Wharncliffe Viaduct at Hanwell will
be found at p. 172, and of the Maidenhead bridge at p. 173.
The line from Twyford to Reading was opened in March 1840, and from
Reading to Chippenham by May 1841. Meanwhile the portion from Bristol
to Bath had been opened in August 1840. The last division, namely, that
from Chippenham to Bath, containing the Box Tunnel, was opened on June
30, 1841; and the railway was completed throughout its whole length.

A considerable part of the history of the Great Western Railway is
connected with the adoption on it of the broad, or 7-foot gauge, and will be
dealt with in the next chapter, in which is also given some account of the
longitudinal system of permanent way.
The bridges are described in Chapter VII.; but some of the other works
may be noticed here.
In laying out the line, Mr. Brunel endeavoured to make it as straight and
as level as possible throughout, and to concentrate those changes of level,
which could not be avoided, into short inclines, to be worked, if necessary,
by auxiliary power.
Accordingly the line is thus divided:—

Miles Yards
Level, or with an inclination not exceeding 4 feet in the mile 67 88
Above 4 feet, and not exceeding 8 feet in the mile 47 110
Steep inclines 3 1210

The steep inclines are two in number, of a gradient of 1 in 100, or about
53 feet in a mile, and descend towards the Bristol end of the line.
The Wootton Basset incline, 85½ miles from London, is 1 mile 550
yards long.
The second incline is at Box, 99 miles from London, and is 2 miles 660
yards in length. An assistant engine is still occasionally used to work heavy
trains at this point.
On this incline the line passes through the Box Tunnel. This tunnel is the
first out of London, and could only have been dispensed with by taking a

circuitous route several miles longer than that adopted by Mr. Brunel.
The tunnel is 1⅞ mile in length, and is ventilated by six shafts. They are
30 feet in diameter, and from 70 to 300 feet deep.
The Box Tunnel had been the subject of much criticism before the works
were commenced; and during its actual construction it did not escape the
unfavourable notice of those who were ignorant of the difficulties which
presented themselves, and the means which had been taken to overcome
them. Indeed, for some time after the opening of the line, there were
travellers who used to avoid the terrors of the tunnel by posting along the
turnpike road in that part of their journey.
Mr. Brunel never troubled himself about the ordinary gossip which is
always circulated concerning any remarkable work; but matters assumed a
different aspect when, a year after the completion of the tunnel, doubts were
expressed as to its safety by an eminent geologist, at a meeting of the
Institution of Civil Engineers. Mr. Brunel, who was on terms of friendly
intercourse with the speaker, addressed to him the following letter:—
June 21, 1842.
I assure you, my dear Sir, that when my attention had been drawn to the statements reported to
have been made by you on this subject, I refrained as far as possible from expressing any opinion. I
thought it my duty to read the notes taken, but I never said that I thought your statements were
correct. Indeed, I had hoped to have avoided the necessity of making any observations upon these
statements; but as a letter to Mr. Saunders on such a subject is almost the same thing as if it were
addressed to myself, and as it was shown to me, it would not be candid towards you if I now
refrained from saying, that the opinions you are reported to have expressed with respect to the Box
Tunnel are by no means considered correct, either by myself or by those others who, from being
intimately acquainted with the rock as it was really found, and the works as they were really
executed, are capable of judging.
In the notes shown to me the observations alluding to this work in particular, as an illustration of
the views you were explaining, appear to have been curtailed, and the allusions rendered somewhat
less direct; but still the inference unavoidably to be drawn from them is, that the back joints, as we
call them, and other defects which exist originally, or which show themselves after a time, in this
rock, are not well known, and tolerably well understood and guarded against, by practical engineers,
and even by our workmen. In this opinion I assure you you are mistaken. Ignorant as I may probably
be myself of the science of geology, I cannot have been engaged for several years in making very
extensive excavations, probably the largest hitherto made, in this particular rock, having also the
opportunity of examining very old and large quarries in the same rock and close to the line, having
among my assistants men not meanly acquainted with this particular branch of geology, and
surrounded by workmen of considerable experience, I cannot have gone through such a study without
acquiring a very intimate and practical knowledge of the structure and peculiarities of the particular
mass of rock which is now in question; and I will say frankly what I feel upon this point, which is,
that I ought now to possess a more thorough and practical knowledge of this particular rock and its
defects, and the best mode of remedying them, than even you yourself, with your immeasurably
greater scientific knowledge of rocks generally.

The opinion you are said to have expressed of there being great danger of some serious accident
occurring in the tunnel is, I am firmly convinced, erroneous; at all events the reason given convinces
me that you have not become acquainted with the means which have been taken by me to examine
and to ascertain the security of every part of the rock, to remove or to support with masonry any part
not so ascertained to be secure, or with the precautions taken to prevent any such accidents as those
you have imagined. And notwithstanding the heavy responsibility which rests upon me, from all
which you gentlemen of science are, happily for yourselves, so free, I feel that as regards the works
of the Box Tunnel everything necessary has been done to render them secure, and that the doubts and
fears you have so easily raised, but which it might be more difficult again to set at rest, are entirely
unfounded.
In conclusion, I must observe that no man can be more sensible than I am of the great advantage
it would be to me as a civil engineer to be better acquainted with geology, as well as with many other
branches of science, that I have endeavoured to inform myself on the subject, and that I have not
altogether thrown away the many opportunities afforded me in my professional pursuits; but that if
from a conviction that you possessed information far more extensive than mine, if from doubts of the
sufficiency of my abilities or the means I was likely to bring to bear upon the subject, if from a fear
of such consequences as you now anticipate, you had kindly, on any one of the many occasions when
I have had the pleasure of meeting you, intimated that you had any suggestions to make to me, I
should have been anxious to have availed myself of your assistance. But after the lapse of years, the
first intimation I have of such doubts is the very public expression of a very strong opinion, which, if
weight be attached to it, must tend to alarm the public unnecessarily, and to injure the value of the
property of individuals who have embarked several millions in that property.

Between Chippenham and Bristol the nature of the building stone
enabled Mr. Brunel, at moderate cost, to make the bridges, tunnel fronts,
and stations ornamental features in the picturesque scenery through which
the railway passes.
He took great pleasure in finishing minutely the various designs, and
making them correct in their proportions and details. One tunnel front, near
Bristol, may be singled out for especial mention. During its construction a
part of the ground behind slipped away, and it became unnecessary to
complete the top of one of the side walls. It was therefore left unfinished,
and was planted with ivy so as to present the appearance of a ruined
gateway.
The roofs of the Bath and Bristol stations are of large span, and are
handsome architectural structures. They are each in the form of a Tudor
arch; the Bristol roof is 72 feet span, and the Bath roof 50 feet span. The
framing is an example of a peculiar form of construction, somewhat
analogous to that adopted in the large shipbuilding sheds in the dockyards.
There are no cross tie-rods, but each principal of the roof is formed of two
frameworks, like cranes, meeting in the middle of the roof; the weight being
carried on columns near the edge of the platform, and the tail ends of the
frames held down by the side walls. As the two frames do not press against

each other at their meeting point at the ridge of the roof, there is no outward
thrust. The side walls being on a viaduct could not without difficulty have
been made to resist a horizontal thrust.
At the Bristol station Mr. Brunel introduced hydraulic machinery for
working lifts. By these the waggons were lowered to and raised up from the
goods shed, which was placed at the level of the ground, about 12 feet
below the railway.
Although the works already described were completed in 1841, the
permanent terminus at Paddington was not commenced till the year 1849. It
was completed in 1854. Previously to that time a temporary station had
been used, the booking offices being under the arches of the Bishop’s Road
bridge.
As the level of the railway was lower than that of the surrounding land,
no exterior architectural effect could be produced; but Mr. Brunel took this
opportunity to carry out his views as to the proper structural use of metal in
works of this description.
In the design of the ornamental details, he obtained the assistance of Mr.
(now Sir Matthew) Digby Wyatt.
The interior of the principal part of the station is 700 feet long and 238
feet wide, divided in its width by two rows of columns into three spans of
68, 102, and 68 feet, and is crossed at two points by transepts 50 feet wide,
which give space for large traversing frames. The roof is very light,
consisting of wrought-iron arched ribs, covered partly with corrugated iron
and partly with the Paxton glass roofing, which Mr. Brunel here adopted to
a considerable extent. The columns which carry the roof are very strongly
bolted down to large masses of concrete, to enable them to resist sideways
pressure.
This station may be considered to hold its own in comparison with the
gigantic structures which have since been built, as well as with older
stations. The appearance of size it presents is due far more to the
proportions of the design than to actual largeness of dimension. The spans
of the roof give a very convenient subdivision for a large terminal station,
dispensing with numerous supporting columns and at the same time
avoiding heavy and expensive trusses. The graceful forms of the
Paddington station, the absence of incongruous ornament and useless
buildings, may be appealed to as a striking instance of Mr. Brunel’s taste in

architecture and of his practice of combining beauty of design with
economy of construction.
The goods station was erected at about the same time as the passenger
station, and is remarkable for the completeness of its arrangements, and for
the great use made of hydraulic machinery. This is also applied in the
passenger station.[45]
In connection with the Paddington station mention may be made of the
Great Western Hotel, which was built at the extremity of the land belonging
to the railway company.
When, in 1854, no tenant could be found for it, a few of the shareholders
of the Great Western Railway, being unwilling that the building should
remain empty and be a loss to the proprietors, formed themselves into a
company to lease and work the hotel. Mr. Brunel became a Director, and
shortly afterwards (in December 1855) the chairman. He occupied this post
till his death, by which time the hotel had become very prosperous. He
found attendance at the meetings of the Directors and the supervision of the
management of the hotel a very agreeable relaxation from the more
important duties which took him to Paddington.

The branches and extensions of the Great Western Railway, as far as
their history affected the general interests of the company, are referred to in
the chapter on the broad gauge. Branches were opened to Oxford in 1844,
to Windsor in 1849, to Wycombe in 1854, to Uxbridge in 1856, to Henley
in 1857, and to Brentford in July 1859.

The Bristol and Exeter Railway is a continuation of the Great Western
Railway, and was opened to Exeter in 1844. The two portions of it, from
Bristol to Taunton, and from Taunton to Exeter, are in marked contrast to
each other. The former part of the line is almost level, and has very easy
curves. Between Taunton and Exeter it passes over the high ground on the
borders of Devonshire, with the Whiteball Tunnel at the summit, ⅝ mile in
length. On this part of the line there are long gradients of from 1 in 80 to 1
in 120. Mr. Brunel resigned the position of engineer in 1846, in
consequence of differences having arisen between the Bristol and Exeter
and the Great Western Companies, which, in Mr. Brunel’s opinion, made it
impossible for him to continue engineer to both railways.

The South Devon Railway, and the adoption on it of the Atmospheric
System, are described in Chapter VI. In connection with this line is the
important Torquay branch, and the railway in continuation of it to
Dartmouth. This was completed as far as Paignton during Mr. Brunel’s
lifetime.
The South Devon and Tavistock Railway branches off from the South
Devon Railway near Plymouth, and has several large viaducts.
On the Cornwall Railway from Plymouth to Truro, and the West
Cornwall Railway from Truro to Penzance, the most remarkable works are
the viaducts, and the Royal Albert Bridge.
In the case of the Cornwall Railway, it became necessary to reduce the
capital expenditure, even at the cost of increasing the charges for
maintenance. With this object the line was re-examined and modifications
introduced, principally by an increase in the extent of viaduct. These lines
pass through a very difficult country; involving the adoption of steep
gradients and sharp curves. Mr. Brunel, in a memorandum written in 1845,
after having explained his reasons for considering that the prejudicial
effects of gradients and curves were commonly overrated, gives the
following opinion in reference to the proposed Cornwall Railway:—
I must not be understood to argue against the advantage of straight lines or large and easy curves,
but I wish to show that where small curves are unavoidable, they can in practice be so constructed as
not to be very prejudicial; and I consider that the character of the country in Cornwall is such that no
railway can be constructed at any moderate expense without either sacrificing all consideration for
the interests of localities and the position of the population to the mere choice of levels, or without
steep gradients and sharp curves.

The principal lines branching off from the Great Western, and since
incorporated with it, are, on the south, the Berks and Hants, from Reading
to Basingstoke and Hungerford; and the Wilts and Somerset, to Weymouth
and Salisbury. On the north-west is the Cheltenham and Great Western
Union Railway, from Swindon to Cheltenham and Gloucester. This line
passes through the Cotswold Hills at Sapperton by a tunnel 1⅜ mile in
length. The Gloucester and Dean Forest Railway runs from Gloucester to
Grange Court, and thence to Ross and Hereford.
The South Wales Railway, which extends from Grange Court to Milford
Haven, contains a tunnel at Swansea ⅓ mile long, and some of Mr. Brunel’s
most important works, including the Chepstow bridge and several other
bridges of considerable size, and the viaducts at Landore and Newport.

There are also on this line four opening bridges across navigable channels.
The works at the termination of the line at Neyland, in Milford Haven, are
described in Chapter XIV. Mr. Brunel considered that Milford Haven, with
its excellent harbour, which can be entered at all times of tide by the largest
vessels, would probably become a great port for ocean steamers, and
especially for the ‘Great Eastern’ and ships of her class.
There are also in South Wales the following railways: the Taff Vale, the
Vale of Neath, the Llynvi Valley, and the South Wales Mineral. The Taff
Vale, a line from Cardiff to Merthyr, was opened on the narrow gauge in
1841.[46] On this railway is the lofty masonry viaduct at Quaker’s Yard.
On the Vale of Neath Railway, from Neath to Aberdare and Merthyr,
there is a tunnel, near Merthyr, 1¼ mile long, and 650 feet below the
summit of the hill.
Full advantage is taken on this railway of the facilities which the broad
gauge offers for heavy traffic. The line has long steep gradients, and the
locomotives used on it, of the class known as tank engines, are of great
power. One of these gradients is 4½ miles long, with an inclination of 1 in
50. Large quantities of coal are brought down by this railway to the
Swansea and Briton Ferry Docks. The coal of South Wales is of a friable
nature, and, in order to avoid the breakage consequent on the ordinary mode
of shipping coal, by tipping it down a shoot, Mr. Brunel introduced on a
large scale the use of trucks carrying four iron boxes, each box about 4 feet
8 inches cube, and containing two and a half tons of coal. At the docks
machinery is provided by which each box is lowered down into the hold of
the ship, and the under side being allowed to open, the coal is deposited at
once on the bottom of the vessel.
The Llynvi Valley Railway is a short line, leading from the South Wales
Railway at Bridgend into the coal and iron districts.
The South Wales Mineral Railway is another line of the same class. It
passes through a very heavy country, and has on it a self-acting incline of 1
in 9, ¾ mile long, worked by a rope, and a tunnel ⅝ mile long, and 470 feet
below the surface.
In connection with the South Wales district is the Bristol and South
Wales Union Railway, a line running from Bristol to the banks of the
Severn, across which the traffic is carried by a steamer to a short branch
from the South Wales Railway on the other side. This railway had been for

a long time contemplated, and Mr. Brunel devoted much time to a careful
investigation of the Severn in order to determine the most suitable point for
the crossing. He decided that the best place would be at what is known as
the New Passage. The arrangements had to be made in accordance with the
requirements of the Admiralty. Trains run to the end of timber piers
extending into deep water, and there are staircases and lifts leading to
pontoons, alongside which a steamer can come at all times of tide. The tide
at this part of the Severn rises 46 feet.
The three railways last mentioned were not completed during Mr.
Brunel’s lifetime.

The Bristol and Gloucester Railway, on which is the tunnel at Wickwar,
¾ mile long, was opened in 1844, and passed into the hands of the Midland
Company in 1846.

The northern extensions of the Great Western Railway are the Oxford
and Rugby, constructed as far as Fenny Compton; the Birmingham and
Oxford Junction; and the Oxford, Worcester, and Wolverhampton Railways.
Mr. Brunel ceased to be engineer of the last-mentioned company in
1851, and the works were completed by Mr. Fowler. The Oxford,
Worcester, and Wolverhampton line has since, under the title of the West
Midland, become a part of the Great Western Railway.

In Ireland Mr. Brunel was engineer of the line from Dublin to Wicklow,
round Bray Head, and of a line from Cork to Youghal.

He laid out two railways in Italy, the line from Florence to Pistoja, and
that across the Apennines from Genoa to Novi and Alessandria, in the
direction of Turin and Milan. He acted as engineer during the construction
of the former line; but the works of the latter were carried out by the
Sardinian Government.

One of the last of Mr. Brunel’s important railways was the Eastern
Bengal Railway, a line of about 100 miles in length, in a north-easterly
direction from Calcutta. He took a great interest in the work and devoted

much time to the special arrangements and designs, and to the best way of
crossing the Ganges and its branches in the future extension of the railway;
but no part of it was opened during his lifetime.

It was impossible for Mr. Brunel to look after all his works to the same
extent as he had done in the case of the Great Western Railway; and he was
compelled to spend a very considerable amount of time in attendance on
Committees of the Houses of Parliament on behalf of the railways to which
he was engineer. Mr. Brunel frequently regretted this, and considered it a
great evil that engineers were prevented by their duties during the session
from attending properly to the construction of their works. He endeavoured
as far as possible to superintend the execution of his different undertakings.
He availed himself of every opportunity of examining them, and was
acquainted throughout with all the designs which were prepared. He would
take advantage of two or three free days to go down to the distant works in
South Wales or in Cornwall, looking after details, such as the pickling tanks
for timber, and the masonry of the viaducts.
He was fortunate in the selection of the members of his staff, and in his
organisation of it. He had a rare power of utilising the capabilities of his
different assistants; and although he had to deal with a great variety of men,
he managed that they should work in harmony with him. From the complete
personal supervision Mr. Brunel sought to maintain over all his works, his
assistants had not perhaps so many opportunities of independent action as
they might otherwise have obtained, but they had, on the other hand, the
advantage of constant personal communication with their chief.
After the time when Mr. Brunel’s works became so numerous, and his
time so much occupied, that he could not exercise in person that general
supervision which he conceived to be necessary, he was ably assisted by
Mr. Robert Pearson Brereton, who, on the death of Mr. Hammond in 1847,
became the chief of his engineering staff.
Mr. Brunel rarely made any changes in the personnel of his office. Mr.
Brereton had become one of his assistants in 1836; and his secretary, the
late Mr. Joseph Bennett, came to him in the same year.

The Great Western Railway retained its early place in his affections, and
among his most valued friends were members of the Board of Directors,

Mr. Saunders the Secretary, and other officers of the company. When in the
last year of his life he was obliged to go to Egypt for his health, it was a
matter of deep anxiety to him lest his absence from England should cause
any alteration in his relations with the Company, and it was a source of
great pleasure to him that no such consequences followed.

Mr. Brunel’s position as confidential adviser of so large a number of
railway companies gave him frequent opportunities of acting as mediator
between contending parties; and his decisions were always received with
respect, for he was known to be scrupulously just.
Besides the more friendly task of reconciling opponents he had a large
practice as a referee under Acts of Parliament and orders of the superior
courts; and displayed in these matters great judicial abilities.
In all the causes and parliamentary contests affecting the various
companies of which he was engineer, Mr. Brunel was a very important
member of the preliminary consultations, and during the proceedings
counsel relied with confidence on his suggestions.

One of the most arduous parts of his duty, as engineer of the Great
Western Railway Company, was connected with the conduct of the great
cases of Ranger and MacIntosh. To the former of these reference is made in
the letter printed below, at p. 478. The MacIntosh case, which was
commenced shortly after the opening of the line, was not concluded before
Mr. Brunel’s death. He was compelled to devote a considerable portion of
his time to it, even after his return home in the evening, during the launch of
the ‘Great Eastern.’

Mr. Brunel had a very high reputation as a witness. Mr. St. George
Burke, Q.C., has communicated a memorandum on this subject.
‘As a witness he could always be relied on as a perfect master of the case he had to support, and
he had the rare quality of confining his answers to a simple reply to the questions put to him, without
appearing as an advocate. He was, however, extremely particular as to the questions which should be
put to him in his examination in chief, and was therefore never satisfied to entrust the preparation of
his proof to the solicitor, without revising it himself.
‘In his cross-examinations he was generally a match for the most skilful counsel, and by the
adroitness of his answers would often do as much to advance his case as by his examination in chief.

‘He was almost as much of a diplomatist as an engineer, and knew perfectly well how to handle a
case in the witness-box so as to leave no loophole for his opponents to take advantage of. At the same
time he was a perfectly honest witness, and while he avoided saying more than was necessary for the
advancement of the cause in which he was engaged, he would have scorned to say or imply anything
by his evidence inconsistent with strict truth.
‘Although he had attained to great celebrity as a witness, the committee room being crowded to
hear him, he always declined to engage in the very lucrative work of a professional witness. He made
a rule never to appear except on behalf of undertakings of which he was the engineer, or with which
his own companies were interested. To help a friend, he occasionally but very rarely broke through
this resolve; but, whether he appeared in support of his own plans or those of others, there were few,
if any, professional men whose evidence carried more weight than his did before Parliamentary
Committees.’

The following memorandum from Mr. George T. Clark, of Dowlais,
formerly one of Mr. Brunel’s assistants, contains his recollections of Mr.
Brunel during the construction of the Great Western Railway:—
‘I made your father’s acquaintance, rather characteristically, in an unfinished tunnel of the Coal-
pit Heath Railway; and when the shaft in which we were suspended cracked and seemed about to
give way, I well remember the coolness with which he insisted upon completing the observations he
came to make. Shortly afterwards I became, at his request, his assistant; and during the parliamentary
struggle of 1835, and the subsequent organisation of the staff, and commencement of the works of
the Great Western, I saw him for many hours daily, both in his office and in the field, travelled much
with him, and joined him in the very moderate recreation he allowed himself.
‘These two years, and the preceding year, 1834, were, I apprehend, the turning points of his life.
His vigour, both of body and mind, were in their perfection. His powers were continually called forth
by the obstacles he had to overcome; and the result of his examinations in the committee rooms
placed him, in the opinion of the members of the legislature, and of his own profession, in the very
first rank of that profession, both for talents and knowledge.
‘I wish I could convey to you even a tolerable idea of your father as he was in those years, during
which I knew him intimately, and saw him often under circumstances of great difficulty.
‘He was then a young man, but in the school of the Thames Tunnel he had acquired a close
acquaintance with all kinds of masons’ and carpenters’ work, the strength and cost of materials,
bridge building, and constructions under water, and with the working of the steam engine as it then
stood. It happened not unfrequently that it was desirable to accept the tender of some contractor for
railway work whose prices upon certain items were too high, and then it became the engineer’s
business to go into the details and convince the contractor of his error. On such occasions Brunel
would go step by step through the stages of the work, and it was curious to see the surprise of the
practical man as he found himself corrected in his own special business by the engineer. Thus, I
remember his proving to an eminent brickmaker who had tendered for the Chippenham contract that
the bricks could be made much cheaper than he supposed. He knew accurately how much coal would
burn so many bricks, what it would cost, what number of bricks could be turned out, what would be
the cost of housing the men, what the cartage, and how many men it would require to complete the
work in the specified time. The contractor was astonished; asked if Mr. Brunel had ever been in the
brick trade, and finally took and made money by the contract at the proposed figure.
‘In the case of the Maidenhead bridge, the contractor being alarmed at learning that the arch was
the flattest known in brick, Brunel pointed out to him that the weight which he feared would crush
the bricks, would be less than in a wall which he, the contractor, had recently built, and he convinced
him by geometry, made easy by diagrams, that the bridge must stand. Knowledge of detail Brunel

shared with the carpenter, builder, or contractor for earthwork, and he was their superior in the
accuracy and rapidity with which he combined his knowledge, and arrived at correct conclusions as
to the cost of the work and the time it would take to execute it.
‘In talking to landowners and others whose opposition it was important to overcome, I have often
been struck by your father’s great powers of negotiation. The most absurd objections—and there
were many such—were listened to with good humour, and he spared no pains in explaining the real
facts, so that it sometimes happened that he converted opponents into supporters of the railway. In the
course he took there was much skilful diplomacy, but there was no dishonesty, no humbug. He was
very frank and perfectly sincere. His object was to impart his own convictions, and in that he often
succeeded.
I never met his equal for sustained power of work. After a hard day spent in preparing and
delivering evidence, and after a hasty dinner, he would attend consultations till a late hour; and then,
secure against interruption, sit down to his papers, and draw specifications, write letters or reports, or
make calculations all through the night. If at all pressed for time he slept in his armchair for two or
three hours, and at early dawn he was ready for the work of the day. When he travelled he usually
started about four or five in the morning, so as to reach his ground by daylight. His travelling
carriage, in which he often slept, was built from his own design, and was a marvel of skill and
comfort. This power of work was no doubt aided by the abstemiousness of his habits and by his light
and joyous temperament. One luxury, tobacco, he indulged in to excess, and probably to his injury.
At all times, even in bed, a cigar was in his mouth; and wherever he was engaged, there, near at hand,
was the enormous leather cigar-case so well known to his friends, and out of which he was quite as
ready to supply their wants as his own.
His light and joyous disposition was very attractive. At no time was he stern, but when travelling
or off work he was like a boy set free. There was no fun for which he was not ready. On the old Bath
road, on a Wiltshire chalk hill-side, is cut a large horse, the pride of the district, and only inferior in
reputation to that of the famous Berkshire vale. The people of the district, afraid to lose their coach
traffic, were violently opposed to the Great Western Railway Bill. Talking over this one evening,
some one suggested turning the horse into a locomotive. Brunel was much amused at the idea, and at
once sketched off the horse from memory, roughly calculated its area, and arranged a plan for
converting it into an engine. Ten picked men were to go down in two chaises, and by moonlight to
peg and line out the new figure, and then cut away the turf, and with it cover up as much of the horse
as might be left. From the tube was to issue a towering column of steam, and below was to be
inserted in bold characters the offensive letters G. W. R. It was, of course, not intended to carry this
joke into execution, but Brunel often alluded to it, and laughed over the sensation it would have
created.
‘He possessed a very fine temper, and was always ready to check differences between those
about him, and to put a pleasant construction upon any apparent neglect or offence. His servants
loved him, and he never forgot those who had stood by his father and himself in the old Tunnel days
of trouble and anxiety.
‘No doubt the exertions of those three years, though they laid the foundation, or rather built the
fabric, of his reputation, also undermined his constitution, and eventually shortened his life.
Everything for which he was responsible he insisted upon doing for himself. I doubt whether he ever
signed a professional report that was not entirely of his own composition; and every structure upon
the Great Western, from the smallest culvert up to the Brent viaduct and Maidenhead bridge, was
entirely, in all its details, from his own designs.’

In the press of work and the altered circumstances under which he
superintended the construction of his later railways, many changes
inevitably followed. The open britzska gave place to a close travelling

carriage, which in its turn became useless; and no time was left for fun or
practical jokes; but the same energy of mind and the same kindliness of
heart remained uninfluenced by increasing occupations or advancing years.

CHAPTER V.

THE BROAD GAUGE.

ORIGIN OF THE ORDINARY GAUGE OF RAILWAYS—ADOPTION BY
MR. BRUNEL OF THE BROAD GAUGE ON THE GREAT WESTERN
RAILWAY—REASONS FOR ITS ADOPTION—THE PERMANENT WAY—
REPORTS OF MR. NICHOLAS WOOD AND MR. JOHN HAWKSHAW, 1838
—EXTRACT FROM REPORT OF DIRECTORS OF GREAT WESTERN
RAILWAY COMPANY (DECEMBER 20, 1838)—EXTENSION OF THE
BROAD GAUGE SYSTEM—BREAK OF GAUGE—ROYAL COMMISSION
ON THE GAUGE OF RAILWAYS, 1845—LETTER OF MR. BRUNEL ON
THE BROAD GAUGE (AUGUST 6, 1845)—GAUGE ACT OF 1846—THE
MIXED GAUGE—REPORT OF RAILWAY COMMISSIONERS, 1847—
NORTHERN EXTENSIONS OF THE GREAT WESTERN RAILWAY—
ADVANTAGES OF THE BROAD GAUGE—PARTIAL ABANDONMENT OF
THE BROAD GAUGE.

THE railways designed by Mr. Brunel were, with a few exceptions,
distinguished from those in all other parts of England by a peculiarity in the
width between the two rails forming each line of way, or in what is called
the gauge. In most railways, the distance between the internal edges of the
rails is 4 feet 8½ inches, being what is termed the narrow gauge; on Mr.
Brunel’s railways, it was seven feet, or what is termed the broad gauge.

The gauge of the earlier railways, which were but a modification of the
old wooden tramway, was made that of the tram plates which they
superseded; and this had been originally fixed to suit the distance between
the wheels of the country carts in the north of England.
When Mr. George Stephenson introduced the locomotive engine, the
gauge of the lines in the Northumberland district had been already fixed. In
laying out the Stockton and Darlington line (1821-1825) he saw no reason
to depart from the gauge he had previously adopted; and, indeed, some of
the waggons to be used on this line were brought from the Northumberland
collieries. In this way the first important railway in England was made with
the gauge of 4 feet 8½ inches; not from a deliberate choice of this width on
the ground of any peculiar advantages, but from the mere fact of its already
being established elsewhere.

In the construction of the Manchester and Liverpool Railway, in 1826,
the same gauge was adopted as on the Stockton and Darlington; this course
was also followed by the Grand Junction and the London and Birmingham
Railways, and thus the 4 feet 8½ inches gauge became established in that
part of the country.

Long experience appears to have determined the general type of wheeled
vehicles: the wheels being of somewhat large size, and the body placed
between them, so as to come down close upon the axle-tree.
This type, which gives obvious advantages in a mechanical point of
view, appears to have been adhered to in all railway vehicles used before
the opening of the Liverpool and Manchester Railway; these, however,
were chiefly coal-waggons. But on the Liverpool and Manchester Railway
it was soon perceived that the great increase of carrying power which the
railway afforded must be met by a corresponding increase of space in the
rolling stock, as it was necessary to accommodate light bulky goods and
passenger traffic. The available width between the wheels was limited to
about 4 feet 6 inches, and to carry in this width any large amount of cotton
goods, or of passengers, would have required a train of an inordinate length.
To meet this difficulty a new form of vehicle was designed; the wheels were
made small, and the body was raised and widened out, projecting on either
side over the tops of the wheels.
The earliest description of this form of waggon is contained in the
second edition of Wood’s ‘Practical Treatise on Railroads,’ published in
1832, about two years after the opening of the Liverpool and Manchester
Railway. In Plate III., Mr. Wood shows a truck with a raised platform
overhanging the wheels, and adapted for carrying loose boxes of coals;
adding, in the description:
Although the drawing shows only the form of boxes used for the conveyance of coals, yet it will
readily occur that the form can be varied to suit the carriage of any kind of articles; the framework or
body of the carriage being raised above the wheels, the breadth can be extended to any width which
the distance between the railways [i.e. between the up and down lines of road] will admit (p. 75).

Such was the state of matters when, in the year 1833, Mr. Brunel was
appointed Engineer of the Great Western Railway. With the view of leaving
the question of gauge open for future consideration, he procured the
omission in the Great Western Act of a clause defining it. He came to the

conclusion that it would be desirable to adopt a wider gauge, and he
recommended this measure to the Directors in a report dated October 1835.
[47]

In October 1836 a Royal Commission, consisting of Mr. Drummond,
Under-Secretary for Ireland, Mr. R. Griffith, Colonel (now Field-Marshal)
Sir John Burgoyne, R.E., and Professor Barlow, of Woolwich, was
appointed to report on the establishment of railways in Ireland. They
considered carefully the question of gauge, and their arguments in favour of
an increase in the gauge were afterwards stated by Mr. Brunel to be
identical with his own.
They drew attention to the advantage of large wheels, the use of which
would be facilitated by a wider gauge; and they thought it a matter of
importance to be able to place the bodies of the carriages between the
wheels, instead of over them.

It was the width of the carriages, and not the distance between the rails,
that determined the general dimensions, and therefore the cost, of the works
of a railway. Mr. Brunel saw many advantages to be gained by an increase
in the gauge, even while retaining the existing dimensions of carriages; and
he thought it unwise at the commencement of a work of such magnitude as
the Great Western Railway to retain a limit the inconvenience of which had
already become apparent.
He says, in his evidence before the Gauge Commission:
Looking to the speed which I contemplated would be adopted on railways, and the masses to be
moved, it seemed to me that the whole machine was too small for the work to be done, and that it
required that the parts should be on a scale more commensurate with the mass and the velocity to be
attained. (Q. 3924.)

The width between the rails being the fundamental dimension of ‘the
whole machine,’ on which its entire development must depend, Mr. Brunel
proposed to begin by the enlargement of this dimension, and recommended
that on the Great Western Railway the gauge should be seven feet. He
considered that the whole of the parts of the railway and of its rolling stock
would be susceptible of continual, though gradual improvement, and that it
was highly advisable to remove, in the outset, a great obstacle in the way of
this progress.

He did not in the first instance propose any important change in the
details as consequent on the wider gauge; and in regard to one of the
principal points, the diameter of the wheels, he said:—
I am not by any means prepared at present to recommend any particular size of wheel, or even
any great increase of the present dimensions. I believe they will be materially increased; but my great
object would be in every possible way to render each part capable of improvement, and to remove
what appears an obstacle to any great progress in such a very important point as the diameter of the
wheels, upon which the resistance, which governs the cost of transport and the speed that may be
obtained, so materially depends. (Report in Appendix I. p. 532.)

Mr. Brunel also looked forward to the advantages which a wider gauge
would give for the construction of the locomotive engines. Difficulties had
been already experienced from the limited width between the wheels, which
cramped the machinery, rendering it difficult of access for repairs; it also
limited the size of the boiler and fire-box, on which the power depended.
For this reason Mr. Brunel considered that a wider gauge would present
great advantages, as it would allow the locomotives to be constructed of
greater power, and with their machinery arranged in a more advantageous
manner. He also thought that the greater width of base for the carriages
would give increased steadiness and smoothness of motion, with greater
safety, particularly at high speeds, and that there would be the advantage of
being able to use larger wheels for the carriages. Moreover, he had in view
the possibility which the broad gauge would give of adopting wheels of a
still larger diameter without raising the centre of gravity, the body of the
carriage being placed between them, as in the original type of common road
vehicles.
The broad gauge was also considered by Mr. Brunel in prominent
connection with the peculiarly favourable circumstances of the Great
Western line, in regard to its gradients and curves. He thought that ‘it would
not have been embracing all the benefits derivable from the gradients of the
Great Western Railway, unless a more extended gauge was adopted.’ In the
first place, it was evident that a diminution of the frictional resistance would
present the greatest advantage where the gradients were flat. In regard to
curves, the wider gauge was at that time considered by him to be more
advantageously applied where the curves were of large radius than where
they were sharp.[48] On the Great Western Railway both gradients and
curves were remarkably good; with the exception of two inclines of 1 in
100, on which auxiliary power was proposed to be used, there was no

gradient between London and Bristol steeper than 1 in 660, the greater part
of the line being nearly level, and except between Bath and Bristol there
was no curve sharper than about one mile radius.
For these reasons Mr. Brunel thought that unusually high speed might
easily be attained for passengers, and great tractive power for goods. He
said:—

I shall not attempt to argue with those who consider any increase of speed unnecessary. The
public will always prefer that conveyance which is the most perfect, and speed, within reasonable
limits, is a material ingredient in perfection in travelling. (Report in Appendix I. p. 532.)

In deciding that the distance between the rails should be seven feet, Mr.
Brunel seems to have been guided by the principle that the wheels should
be put sufficiently far apart to admit of an ordinary carriage body being
placed between them.[49]
Mr. Brunel did not anticipate that the difference between the gauge he
proposed and that of other railways would lead to any important
inconvenience. The views he held on this subject were expressed fully by
him in a report of December 13, 1838. He says, speaking of the difficulty of
communication between the Great Western and other railways:—
This is undoubtedly an inconvenience; it amounts to a prohibition to almost any railway running
northwards from London, as they must all more or less depend for their supply upon other lines or
districts where railways already exist, and with which they must hope to be connected. In such cases
there is no alternative.
The Great Western Railway, however, broke ground in an entirely new district, in which railways
were unknown. At present it commands this district, and has already sent forth branches which
embrace nearly all that can belong to it; and it will be the fault of the company if it does not
effectually and permanently secure to itself the whole trade of this portion of England, with that of
South Wales and the south of Ireland; not by a forced monopoly, which could never long resist the
wants of the public, but by such attention to these wants as shall render any competition unnecessary
and hopeless. Such is the position of the Great Western Railway. It could have no connection with
any other of the main lines, and the principal branches likely to be made were well considered, and
almost formed part of the original plan; nor can these be dependent upon any other existing lines for
the traffic which they will bring to the main trunk.

Mr. Brunel was not singular in holding the opinion that it would be
desirable to allot a given district to one railway, which might conveniently
serve it by means of a trunk line and branches of a special gauge. In the
Eastern Counties line, designed in 1836, by Mr. Braithwaite, and opened in
1839, a gauge of 5 feet was adopted; and Mr. Robert Stephenson, as
engineer of another line, the Northern and Eastern Railway, branching out
from the Eastern Counties to the northward, adopted the same gauge. It was
not till the Northern and Eastern line was extended, some years afterwards,
that the rails of the whole system were altered to the narrow gauge.

Mr. Brunel’s recommendation was adopted by the Directors of the Great
Western Railway; and, in their report of August 25, 1836, after observing
that the generally level character of the line would greatly facilitate the

attainment of a higher speed of travelling, they pointed out the advantages
of the broad gauge, and stated that engines had been ordered specially
adapted to the nature of the line, which would be capable of attaining with
facility a rate of from thirty-five to forty miles per hour.
The line was opened between Paddington and Maidenhead on June 4,
1838, and the performance of the engines was considered satisfactory, trains
of eighty tons and upwards being drawn at speeds of from thirty-eight to
forty miles per hour.

Notwithstanding these favourable results, the change in regard to the
gauge did not pass unquestioned. Attacks were made on it in various
quarters, and considerable excitement was caused among the shareholders
and the public.
It was asserted that the width of 4 feet 8½ inches was exactly the proper
width for all railways, and that a deviation from it was tantamount to the
abandonment of an established principle which experience had proved to be
correct. It was further alleged that the cost of all the works connected with
the formation of the line would be greatly increased; that the carriages must
be stronger and heavier, that they would not run round the curves, and
would be liable to run off the rails, and particularly that the increased length
of the axles would render them liable to be broken. These were not
advanced as difficulties which, existing in all railways, might be somewhat
increased by the increase of gauge, but they were assumed to be peculiar to
the broad gauge, and fatal to it. Some urgent representations appear to have
been made to the Directors; for in their report of August 15, 1838, they
state, that as the gauge and the permanent way, which had also been the
subject of adverse criticism, had been sources of some anxiety to them, they
had applied to three of the most eminent authorities on the construction and
working of railways—Mr. James Walker, President of the Institution of
Civil Engineers, Mr. Robert Stephenson, and Mr. Nicholas Wood, of
Newcastle-on-Tyne—to undertake a thorough inspection of the line, to
investigate the working of it, and to give their opinion on the plan adopted.
Mr. Walker and Mr. Stephenson declined the task, on the ground that
they did not wish to become embroiled in professional controversy, but Mr.
Wood undertook it; and a similar commission was afterwards given to Mr.
Hawkshaw.

In order to put the shareholders fully in possession of all the information
in their power, the Directors published a very complete statement by Mr.
Brunel on the arrangements adopted by him. It will be seen that in this
report, which is given in Appendix I. p. 525, he states his original
arguments, and answers the objections brought against his plans; and he
contends that the result of experience establishes their success. In regard to
the gauge, he says:—
Everything that has occurred in the practical working of the line confirms me in my conviction
that we have secured a most valuable power to the Great Western Railway, and that it would be folly
to abandon it.

But the two engineers, to whom the consideration of this matter had been
referred, differed materially in opinion from Mr. Brunel. The nature of their
investigations and reports, and of Mr. Brunel’s replies, is stated in the
extracts given below from the report of the Directors in January 1839.

In addition to the question of gauge, another important matter referred to
the consideration of Mr. Wood and Mr. Hawkshaw was the construction of
the permanent way.[50] On the Great Western a construction had been
introduced by Mr. Brunel differing materially from that ordinarily used; and
as defects had shown themselves after the opening of the railway, some
anxiety was felt in reference to it by many of the shareholders.
The subject of the permanent way adopted on the Great Western Railway
does not necessarily belong to the gauge question, and would, perhaps, have
been more properly considered in the chapter on Mr. Brunel’s railway
works; but, as a matter of fact, the controversy concerning it became so
interwoven with that of the broad gauge, that in a historical account it
would be difficult to separate them.
It appeared to Mr. Brunel that, with a view of applying the engine power
to the greatest advantage, particularly in attaining high speed, more
attention ought to be paid to the construction of the permanent way. He
says, in a report dated February 1837:—
It appears to be frequently forgotten that although lofty embankments and deep cuttings, bridges,
viaducts, and tunnels are all necessary for forming the level surface upon which the rails are to be
laid, yet they are but the means for obtaining that end; and the ultimate object for which these great
works are constructed, and for which the enormous expenses consequent upon them are incurred,
consits merely of four level parallel lines, not above two inches wide, of a hard and smooth surface;
and upon the degree of hardness, smoothness, and parallelism (which last has hitherto been very

much neglected) of these four lines depend the speed and cost of transport, and in fact the whole
result aimed at....
In forming all my plans I have looked to the perfection of the surface on which the carriages are
to run, as the great and ultimate desideratum; and in the detail of construction of this last operation,
without which all the previous labour is comparatively wasted, I have always contemplated
introducing all the perfection of materials and workmanship of which it is capable.

With a view to improvement on this point, Mr. Brunel considered it
would be advantageous if two important changes were made. He proposed,
in the first place, to abolish the use of stone blocks for the rails to rest on,
and to substitute timber; and, secondly, to apply the support uniformly and
continuously along the whole length of the rails, instead of only at intervals.
The first of these changes, namely, the substitution of timber for stone,
was not wholly new, for transverse wood sleepers were often used in
exceptional situations; but it was the general opinion that stone, where it
could be applied, formed the best support for the rails,[51] and the exclusive
employment of timber was considered a great innovation.
The other principle, that of ‘continuous bearing,’ was similar to that of
the old wooden and stone tramways; and, even as applied to iron rails it had
been extensively used before, as Mr. Brunel mentions in his report of
August 1838 (see Appendix I. p. 535.)
Mr. Brunel designed for this continuous bearing a peculiar shape of rail,
which, from the form of its section, acquired the name of the ‘bridge rail.’
The rail was bolted down to the longitudinal timbers, and the timbers of the
two rails were connected together at intervals by cross-pieces, called
transoms, bolted to them; these served to keep the two rails at a proper
distance apart. The longitudinal timbers lay on gravel or other ‘ballast,’
which had been found to form the best foundation, as being firm and solid,
easy of adjustment, and allowing free drainage.[52]
Mr. Brunel, however, thought there would be difficulty in giving the
longitudinal baulks a sufficiently solid bearing on the gravel below them.
A similar difficulty had already been experienced with the heavy stone
blocks used on other railways. As a remedy for this, Mr. Stephenson caused
each block to be lifted and dropped several times on its place, so as to
consolidate the ballast below.
The same thing could not be done with a long wooden baulk, and Mr.
Brunel therefore contrived another mode of overcoming the difficulty. Piles
were driven into the ground between the rails, and their heads bolted to the

cross-transoms, the object being to hold the timber framework firmly down.
The gravel was then rammed hard under the longitudinal baulks, to give the
consolidation desired. The result, however, of this mode of construction was
far from successful, and the state of the road, when run over by the trains,
was in many places very defective.[53]
In the course of his enquiry Mr. Wood tried a large number of
experiments on the Great Western and other lines. He was of opinion that
stone blocks afforded a permanently firmer base, and so caused less
resistance to the train, but that there was less noise with continuous timber
bearings, and that they gave a smoother and a more perfect road for high
rates of speed. He thought, however, that the piles were objectionable, and
that the weight of the trains would in the course of time sufficiently
consolidate the foundation. Mr. Brunel accepted Mr. Wood’s conclusions
and abandoned the piling, adopting at the same time larger timbers and
heavier rails.
The experience of the permanent way, as thus altered, fully justified the
favourable anticipations Mr. Brunel had formed of the continuous timber
bearing.[54]

After the reports of Mr. Wood and Mr. Hawkshaw, with Mr. Brunel’s
replies to them, had been circulated among the shareholders, a special
general meeting was called in London, to receive and consider these
documents. It was convened for December 20, 1838, but was adjourned till
January 9, 1839. This meeting was of great importance, not only to the
Company, but to Mr. Brunel personally, as on the resolutions to be passed
depended whether or not his plans should be proceeded with.
He had, however, the warm support of the Directors, as will appear from
the following extracts from their report.
It may be here concisely stated, that Mr. Wood deduces from experiments upon the performance
of engines on the Great Western and other lines, that although a higher rate of speed has been attained
on the former, it would appear only to have been accomplished by the increased power of the
engines, with a much greater consumption of coke when calculated per ton per mile. He ascribes this
result principally to the resistance presented by the atmosphere to the motion of railway trains,
especially at high rates of speed. His remarks on that subject are qualified, however, by the
expression of a doubt as to the value to be assigned to the single set of experiments on each of two
inclined planes, which are quoted as the authority for the degree of atmospheric resistance supposed
to have been discovered.

The reduction of friction by the employment of wheels of increased diameter, and the benefit of
lowering the carriages between the wheels, are affirmed by Mr. Wood as incontrovertible. The
increased stability, and consequent increased steadiness of motion to carriages on the wider base, are
also admitted by him....
The various propositions of doubtful advantage from the wide gauge, as well as of alleged
objection to it, appear to have been thoroughly considered in the report in question. The experiments
on the consumption of coke at high velocities were unfavourable, and, in connection with the theory
of atmospheric resistance, appear to have influenced the mind of Mr. Wood to consider that a seven-
feet gauge was beyond the width which he would deem the best. At the same time, upon a review of
all the circumstances, and considering that there are counteracting advantages, incidental to an
increased width of gauge, he does not think that the result of his enquiries would justify a change in
the dimensions adopted on this line, and he recommends the present width should be retained.
The advice thus given by Mr. Wood, upon mature reflection, being directly at variance with the
conclusion at which Mr. Hawkshaw had previously arrived upon an investigation similarly delegated
to him, it became the duty of the Directors to consider most attentively the train of reasoning and
argument which led the latter to urge such an opposite course. Naturally expecting from that
circumstance to find in his report a clear and definite statement of the positive loss or disadvantages
accruing from the increased width of gauge, the Directors could not fail to remark with some surprise
that he enforces his recommendation, not upon any ascertained injury or failure in the plan, but
almost exclusively upon the presumption that all railways, however disconnected or locally situated,
should be constructed of one uniform width. While he appears to think that it might be an
improvement to have an addition of a few inches, five or six at the most, he still questions the
expediency of any variation from the 4 feet 8½ inches gauge. Mr. Hawkshaw, in his report, also
considers any additional expense upon the gauge, as well as upon the improvement of gradients, to be
undesirable, and assumes it at a scale of augmentation far beyond the real difference of cost. His
estimates on that head are impeached in the engineer’s observations, and no doubt exists in the minds
of the Directors, that the subject, reduced to a mere question of figures, in its present position, would
undeniably show a pecuniary loss to be borne by the Company by any such change of system as he
advocates, even if it were on other grounds deemed advisable. The objection that the wide gauge
might prevent a junction with other lines seems both to Mr. Wood and the Directors to have but little
weight, as applied to the Great Western Railway. Already has the same width been contemplated and
provided for in the extension lines through Gloucestershire to Cheltenham and from Bristol to Exeter.
Any local branches hereafter to be made would undoubtedly follow the same course, and the
proprietors, therefore, may be satisfied that no apprehension need be entertained by them on that
head.
The advantage of following Mr. Wood’s advice, in not making any alteration in the width of way,
has been since most forcibly shown by more recent experiments, which have entirely changed the
results upon which the chief objections to the gauge were founded. The performance of the engines,
shown by Mr. Wood’s experiments in September, gave such a disproportionate result in their power
upon the attainment of high velocities, as to render it all but impossible that the effect could be
entirely produced by the action of the atmosphere on the trains. All doubts were shortly removed by
its being ascertained that a different cause (a mere mechanical defect in the engine itself) had been in
operation. If Mr. Wood had witnessed these recent performances of the engines, he must
unquestionably have changed his opinions as to the means and practicability of carrying full average
loads at a high speed, without the great increased expense of fuel. The Directors have satisfied
themselves of this very important fact, by personally attending an experiment (accompanied by
several gentlemen, among whom was a very eminent practical mechanic), on which occasion the
‘North Star’ took a train of carriages, calculated for 166 passengers, and loaded to 43 tons, to and
from Maidenhead, at a mean average speed of thirty-eight miles per hour, the maximum being forty-
five miles per hour, consuming only 0·95, or less than 1 lb. of coke per net ton per mile, instead of

2·76, say 2¾ lbs., as previously shown. This was accomplished by a mere altered proportion in the
blast pipe of the engine, in the manner explained by Mr. Brunel, being a simple adaptation of size in
one of the parts, which admits a more free escape of steam from the cylinder, after it has exerted its
force on the piston, still preserving sufficient draft in the fire.[55]
It must be almost needless to point out to those who have perused the reports, how importantly
this change bears upon the subject in almost every relation of the enquiry. It negatives the assumption
that the velocity can only be attained by a ruinous loss of power. It establishes beyond doubt that the
consumption of fuel as now ascertained, in proportion to the load, is only one-third of that which
from the former experiments had been the basis of Mr. Wood’s arguments. An analysis in the report
of the performance of the Great Western engines, with heavy loads varying from 80 tons to 166 tons,
shows in every respect a peculiarly satisfactory result at a small cost of fuel, and warrants the
expectation of very great benefit to the Company from the economical transport of goods on the line.
That the expenses of locomotive repairs, especially on that heavy class of repair which arise from
lateral strains on the wheels and framing of the engines, have been materially less than on other lines
is ascertained by very detailed accounts, accurately made and submitted to the Board by the
superintendent of that department. The experience of some months has now enabled the Directors to
witness the progressive improvement in the practical working of the railway. A higher rate of speed
has been generally maintained than on other lines, and at the same time, with that increased speed,
great steadiness of motion has been found in the carriages, with consequent comfort to the
passengers. If speed, security, and comfort, were three great desiderata in the original institution of
railway travelling, the Directors feel sure that the public will appreciate and profit by any
improvements in those qualities, the Company deriving ample remuneration in the shape of increased
traffic. A saving of time upon a long journey, with increased comfort, will necessarily attract to one
line in preference to another many travellers from beyond the ordinary distance of local connection,
and will thus secure a valuable collateral trade which would not otherwise belong to it. It has also a
decided tendency to avert competition, which may with much reason be regarded as the chief peril to
which railway property is subjected.
The Directors, upon a deliberate reconsideration of all the circumstances affecting the permanent
welfare of the undertaking, divesting the question of all personal partialities or obstinate adherence to
a system, unanimously acquiesce in the abandonment of the piles, in the substitution of a greater
scantling of timber, and of a heavier rail, retaining the width of gauge with the continuous timber
bearings, as the most conducive to the general interests of the Company.

The views of the Directors were approved of by the majority of the
shareholders (the numbers being 7,792 for, and 6,145 against); and the
construction of the line was proceeded with according to Mr. Brunel’s
plans.

By June 30, 1841, the whole length of the Great Western Railway was
opened from London to Bristol. Some of the Directors’ reports mention the
fact that the speed uniformly maintained by the engines much exceeded the
ordinary rate of railway travelling, and allude to the ‘general testimony
borne to the smoothness and comfort of the line and carriages.’

As has been before mentioned, extensions and branches on the same
gauge, to all of which Mr. Brunel was engineer, were projected and
ultimately carried out, in accordance with the original scheme of the
undertaking, to Exeter, Plymouth, and Cornwall, and to Gloucester,
Hereford, and South Wales, as well as to Oxford, Windsor, and other towns
in the immediate neighbourhood of the line.
About 1844, the attention of the Company began to be directed to
projects involving extensions of a much more serious character, and which
were destined to have a powerful influence on the position of the gauge
question. During the railway mania, the Great Western Company found it
impossible to stand aloof from the contests which were going on around
them, and thought it necessary, in order to protect their own interests, to
extend their lines beyond the district to which they had originally intended
to confine themselves.
At the general meeting in August, an extension from Oxford to Rugby
was determined on, as ‘of the greatest importance to the Great Western
line.’ About the same time a broad-gauge line was promoted from Oxford to
Worcester, and thence by Kidderminster and Dudley to Wolverhampton, in
order to open an immediate communication with the Staffordshire and
Worcestershire districts. There were also rival projects on the narrow gauge,
promoted by the London and Birmingham Company; and the competing
plans were referred, as was the custom at that time, for the examination of
the Railway Department of the Board of Trade.
In regard to the communication from north to south, through Oxford, the
question was, where the break of gauge should be.[56] The Board of Trade
saw nothing in the relative merits of the gauges to determine this question,
and from commercial considerations, they recommended that the change of
gauge should be made at Oxford. On this and other grounds they considered
that the narrow gauge schemes to the north of Oxford were preferable to
those of the Great Western Railway.
The rival schemes then went before Parliament, and after a protracted
enquiry, obstinately fought between the parties, the decision was given in
favour of the Great Western lines, contrary to the recommendation of the
Board of Trade. It was, however, stated by the chairman of the Commons
Committee that the decision had been founded on the local and general
merits of the respective lines, without any reference to the comparative

merits of the two gauges. On this account some peculiar provisions were
made in the Acts; for though the lines were sanctioned on the broad gauge,
the proprietors were bound also to lay down narrow gauge rails upon them,
if required to do so by the Board of Trade. At the same time the House of
Commons, on the motion of Mr. Cobden, passed a Resolution praying her
Majesty to refer the gauge question to a Royal Commission.
A Commission was issued in July; the Commissioners being three in
number—Sir J. M. Frederic Smith, R.E.; Mr. G. B. Airy, Astronomer Royal;
and Professor Barlow, of the Royal Military Academy, Woolwich. They
took a large amount of evidence, both oral and documentary, and made
some examinations of the working of the two gauges. Their report was
presented to Parliament early in the session of 1846.
Of forty-eight witnesses, thirty-five were advocates of the narrow gauge;
and against these were arrayed but four champions of the broad gauge, all
officers of the Great Western Railway:—Mr. Charles Alexander Saunders,
the secretary; Mr. Seymour Clarke, the traffic superintendent; Mr. (now Sir
Daniel) Gooch, the locomotive superintendent; and Mr. Brunel.
The report was of considerable length, and in it the Commissioners
addressed themselves to three heads of enquiry, viz.:—
1. Whether the break of gauge was an inconvenience of so much
importance as to demand the interference of the legislature.
2. What means could be adopted for obviating or mitigating such
inconvenience.
3. Considerations on the general policy of establishing a uniformity of
gauge throughout the country.
The general conclusions arrived at on these points were thus summed up
by the Commissioners:—
1. That, as regards the safety, accommodation and convenience of the passengers, no decided
preference is due to either gauge, but that on the broad gauge the motion is generally more easy at
high velocities.
2. That, in respect of speed, we consider that the advantages are with the broad gauge; but we
think the public safety would be endangered in employing the greater capabilities of the broad gauge
much beyond their present use, except on roads more consolidated, and more substantially and
perfectly formed, than those of the existing lines.
3. That, in the commercial case of the transport of goods, we believe the narrow gauge to possess
the greater convenience, and to be the more suited to the general traffic of the country.
4. That the broad gauge involves the greater outlay, and that we have not been able to discover,
either in the maintenance of way, in the cost of locomotive power, or in the other annual expenses,

any adequate reduction to compensate for the additional first cost.
Therefore, esteeming the importance of the highest speed on express trains for the
accommodation of a comparatively small number of persons, however desirable that may be to them,
as of far less moment than affording increased convenience to the general commercial traffic of the
country, we are inclined to consider the narrow gauge as that which should be preferred for general
convenience, and therefore, if it were imperative to produce uniformity, we should recommend that
uniformity to be produced by an alteration of the broad to the narrow gauge....

Guided by the foregoing considerations, the Commissioners
recommended that 4 feet 8½ inches should be fixed by law as the standard
gauge of the country; and that as to the existing broad gauge lines, either
they should be altered to the narrow gauge, or some course adopted which
would admit of narrow gauge carriages passing along them.[57]
This adverse report was a great surprise to the supporters of the broad
gauge system, as rumours had led them to hope for a different result.
Immediately after its appearance, several documents were published,
containing powerful and severe strictures on the proceedings and opinions
of the Commissioners. The most important of these was written by Mr.
Saunders, Mr. Daniel Gooch, and Mr. Brunel. It occupied fifty closely
printed folio pages, and was entitled, ‘Observations on the Report of the
Gauge Commissioners, presented to Parliament.’ To this, ‘Supplemental
Observations’ were added, after the publication of the Evidence and the
Appendix to the Report.
In the conclusion of the ‘Observations’ the writers gave a summary of
the points they considered to have been proved in the controversy, namely
—

That the question of ‘break of gauge’ originated as a cloak to a
monopoly.
That even if the gauge were uniform, through trains would be
impracticable.
That the transfer would be of little inconvenience.
That any advantage of small waggons was applicable to the broad gauge,
but that the advantage of large waggons was not applicable to the narrow.
That the competition between the two systems was advantageous.
That the final recommendations of the Commissioners were at variance
with their separate conclusions.

That it would be unjust to refuse to allow the broad gauge to be laid
down on lines for which it was already sanctioned by Parliament.
That the enquiry before the Commissioners was not properly conducted,
and that consequently no legislation ought to be founded on it.
That the data published by the Commissioners were often wrong, and in
some cases led to the reverse of their conclusions.
That greater economy was proved on the broad gauge.
That the broad gauge was superior in the points of safety, speed, and
conveyance of troops.
That the experiments made in the presence of the Commissioners had
demonstrated beyond all controversy the complete success of the broad-
gauge system.
For these and other reasons, a strong protest was made against any
legislative interference with the broad-gauge system.
A reply was published to these arguments; and during the controversy a
large number of pamphlets, articles, and other publications appeared on
both sides.

Mr. Brunel’s views on the whole question, about this time, are concisely
expressed in the following letter, written to a friend in France, who asked
for information on the subject of the broad gauge:—
August 4, 1845.
I am just off for Italy, but write a few hasty lines in reply to Mons. ——’s queries, and which you
must scold him for not addressing direct to me. Nobody can answer such questions but myself, and I
am compelled to be very brief.
In answer to the first, I send a drawing.
Secondly. I see no reason why the ordinary construction of rails, chairs, and sleepers should not
be equally applicable to the wide gauge as to the narrow. I have used them occasionally. I should
think 75 lbs. per yard heavy enough for any purposes.
Thirdly. Within all ordinary limits, certainly in curves of more than 250 metres [12½ chains]
radius, the gauge does not affect the question of curves. The effect of a curve of larger radius than
this appears, both from much observation as from theory, to arise merely from two causes, the one
centrifugal force, which is easily neutralised, and is independent of gauge; the other from the axles
not being able to travel in the direction of the radius, and consequently the wheels not running in a
tangent to the curve. This also is unaffected by the width of gauge. Practically I believe the
conditions are not altered.
Fourthly. The expenses of construction are not dependent on the breadth of gauge unless the total
width allowed for the loads or carriages is thereby or for other reasons increased, which is not a
necessary consequence of a seven-feet gauge.

The wide gauge could be laid upon the London and Birmingham Railway without altering any of
the works, but in constructing the Great Western Railway I thought it desirable to provide for
carrying larger bodies, and I placed the centres of the two railways 13 feet apart, instead of 11 feet,
and therefore my railway became four feet wider in total width.
The increased cost of this, including the cost of land, will vary from 300l. to 500l. per mile.
Fifthly. The increase of width will not increase the weight of an engine (of the same power) 500
lbs., but I avail myself of the larger width to get more powerful engines, and they weigh, with water
in the boiler, 18 to 21 tons. I send a drawing of one; the stroke is 18 inches.
Sixthly. The passenger carriages are all on six wheels, and excessively strong; at present the
framework of carriages and the whole of the waggons are made of iron. The first-class carriages
weigh, with wheels, &c., 7 tons 16 cwt. (17,472 lbs.), and carry 32 passengers. Second-class about
the same weight, and hold 72.
Seventhly and Eighthly. The comparison being on different railways under different
managements and totally different circumstances, no strictly correct comparative results can be
given; and of course the most opposite opinions are entertained and expressed. I believe we travel
much quicker at the same cost and with more ease, and certainly the wear and tear of engines and
carriages is very much less with us than with the other lines; but for the reasons above stated it cannot
be made matter of exact proof, but remains matter of opinion.

The report of the Gauge Commission, on being presented to Parliament,
was referred by the House of Commons to the Board of Trade, who
reported on it in June 1846. They did not, however, concur with the
Commissioners to the full extent of their recommendations; for, while
admitting the break of gauge to be an evil, they could not, having regard to
the circumstances under which the broad gauge companies had been
established, and the interest they had acquired, recommend either that the
broad gauge should be reduced to narrow, or that rails should be laid down
for narrow gauge traffic over all their lines. Such measures would involve
great expense, and they were unable to suggest any equitable mode of
meeting it.
This conclusion necessarily affected the opinion of the Board of Trade in
regard to the several lines under construction connected with the Great
Western Railway, which the Board recommended should be all made on the
broad gauge.
In regard to the broad-gauge lines sanctioned by Parliament from Oxford
to Rugby, and from Oxford to Worcester and Wolverhampton, the Board
determined to exercise their powers in requiring the narrow gauge to be laid
down, in addition to the broad.
The House of Commons adopted the recommendations of the Board of
Trade, and passed a series of resolutions in conformity thereto, and ‘An Act

for regulating the Gauge of Railways’ received the Royal Assent on August
18, 1846.
It was enacted that it should not be lawful to construct any new
passenger railway on any other gauge than 4 feet 8½ inches in England, and
5 feet 3 inches in Ireland.
Exceptions, however, were made in favour of certain lines in the west of
England and South Wales.
The provisions relating to the gauge in the Acts for the Oxford and
Rugby, and the Oxford, Worcester, and Wolverhampton Railways, were left
in force.
The Act also generally excepted ‘any railway constructed or to be
constructed under the provisions of any present or future Act containing any
special enactment defining the gauge or gauges of such railway or any part
thereof.’
This Act, while it professed to establish the narrow gauge as the standard
throughout the kingdom, did so only nominally; in reality, by the words
‘present or future,’ in the passage above quoted, it left the question of the
gauge of any new railway open for the consideration of the committee on
the particular bill; and it only obliged the promoters of the undertaking to
adopt the narrow gauge when no case could be proved by them for the
adoption of some other. This was equivalent to the former state of things, so
that all the agitation of the question had ended in a mere expression of
opinion, and the broad-gauge party were not only left with all their former
liberty, but were encouraged, and almost compelled, to push their system
still farther wherever they could.

About the time of the passing of the Gauge Act, a Board of
Commissioners of Railways was established, to whom the powers formerly
possessed by the Board of Trade were transferred.
One of the first duties of the Commissioners was to provide for the due
compliance with the order of the Board of Trade respecting the introduction
of the narrow gauge, in conjunction with the broad, on the Oxford and
Rugby Railway.
It was proposed to effect this either by laying a narrow gauge line
concentrically between the two rails of the broad gauge, or by laying down
only one additional rail between the two broad-gauge rails, making one of

the latter serve for both broad and narrow gauges. Mr. Brunel recommended
the second of these plans to be adopted on the Oxford and Rugby line.
After a careful consideration of the question, the Commissioners
sanctioned the mixed gauge formed by the introduction of a third rail; this
was accordingly laid down, and none of the dangers which were at the time
prognosticated in reference to it were found to exist. It has been the plan
almost exclusively used in the many cases where the combination of the
two gauges has been required.

In 1846 the Great Western Railway Company had promoted a bill for a
branch to Birmingham from the Oxford and Rugby line at Fenny Compton.
The Act was obtained, but they were defeated on the question of the gauge.
However, after the passing of the Gauge Act, the Company again attempted
to carry the broad gauge to Birmingham. Their application was backed by a
strong memorial from the districts interested, and in June 1847 an order was
passed by the House of Lords directing the Board of Commissioners of
Railways—
To inquire into the accommodation afforded by the several lines of railway now open, or in the
course of construction, or projected, between London and Birmingham; and to report to this House,
early in the ensuing Session of Parliament in what manner they are of opinion that the interests of the
public may be most effectually ecured in regard to such lines; and whether it is expedient that the
broad gauge should be extended to Birmingham; and if so, in what manner such an arrangement can
be carried into effect with the least interference with existing interests....

This, of course, opened up again the whole question of the comparative
merits of the two gauges.
The Railway Commissioners issued a series of queries addressed to the
officials of the Great Western and the London and North Western Railway
Companies, and others. On the part of the Great Western, answers were
given by Mr. Brunel and Mr. Daniel Gooch. Mr. Gooch also furnished the
results, with tables and diagrams, of a very comprehensive series of
dynamometrical experiments, made by him on a mile of straight and level
line on the Bristol and Exeter Railway. These experiments fully
demonstrated the advantages of the broad gauge, and are still the chief
authority on train resistances.[58]
In their report the Commissioners adopted the opinion of the Gauge
Commissioners ‘that a break of gauge was a most serious impediment in the
transport of merchandise, and that the broad gauge did not offer any

compensating advantage so far as that description of traffic was concerned.’
In regard, however, to passenger traffic, they found a case for further
enquiry. They said—
It is notorious that higher speeds, with larger and heavier passenger trains, are regularly
maintained on a part of the line of the Great Western Railway than on any other railway in the
country. This fact is known and greatly appreciated by a very large portion of the public; and no
opinion respecting the extension of the district within which the broad gauge should be adopted is
likely to be received with confidence which is not founded on a full consideration of the
circumstances to which the above fact is to be attributed, and of the extent to which, under differing
circumstances, if attributable to the breadth of gauge, the gauge of the Great Western Railway offers
this advantage (p. 11).

They assumed that the greater speed was due to greater engine power,
and they admitted that the increase of gauge allowed of an increase in the
size and power of the locomotive. They arrived at the result that the broad-
gauge engine ‘can draw on a level an ordinary ‘passenger train of 60 tons
with as much facility at ‘sixty miles an hour as the narrow-gauge engines
can at ‘fifty,’ the advantage, however, diminishing with steep gradients. In
their report the following passages are to be found:—
Such appear to the Commissioners to be the advantages which the broad gauge at present offers;
and although they cannot consider them sufficient to compensate the evils attendant on two gauges, if
it were now possible to obtain uniformity of gauge, yet, as two gauges are established, it appears to
them that it might be expedient, and for the public interest, on account of those advantages, to extend
the broad gauge to Birmingham ... (p. 14.)
By introducing the mixed gauge on the Birmingham and Oxford Junction Railway, the line from
Birmingham by Fenny Compton to London would probably offer, as a broad-gauge railway, as rapid
a communication as the existing direct line;[59] and great as the advantages which the public have
received by the rivalry between the gauges, in the rapid improvement in railway travelling, have
been, it might even be expected that these would be further increased when the two systems are
brought into direct competition, which as yet they have not been (p. 16).

The report of the Railway Commissioners was presented in May 1848.
Their decision was ratified by the passing of an Act in the same session for
extending the broad gauge from Oxford to Birmingham; and the line was
opened in October 1852.
Beyond Birmingham the Great Western Company purchased existing
railways leading through Wolverhampton and Shrewsbury to Chester, and
obtained access to Birkenhead and Manchester. It thus secured a
communication with the great Lancashire towns and the manufacturing
districts.

But all the lines north of Wolverhampton had been constructed on the
narrow gauge, and therefore, unless the broad gauge had been laid down on
these lines, there was a break of gauge between the northern districts and
London.
The break of gauge was found to be a much more serious evil than had
been anticipated by the Great Western Company when they were fighting
their great battle in 1845. For passengers the inconvenience was
unimportant; but for the goods traffic between the manufacturing towns and
London it was serious, partly on account of the expense, but more
especially in consequence of the loss of time. The delay of some hours by
change of waggons, where great competition existed, was fatal.
For these reasons the abolition of the break of gauge became desirable.
The number of narrow-gauge lines had by the year 1861 been so increased
that there was no longer any hope of advantageously extending the broad
gauge in the north. Therefore the mixed gauge was completed to London.
After the establishment of the narrow-gauge communication on the
northern lines of the Great Western, and its prolongation to London, there
was but little inducement to use the broad gauge north of Didcot.

So far as it extended, the broad gauge had exhibited in a marked degree
the advantages Mr. Brunel claimed for it, and which were neither few nor
unimportant.
It may be desirable before concluding this chapter to sum up those
advantages:—
1. It gave the power of constructing more powerful engines, by which
greater speed for passenger trains and greater tractive power for heavy
goods trains were obtained.[60]
2. It gave more space for the convenient arrangement and beneficial
proportions of the machinery, as well as for convenient access to it. In all
these points difficulties had been found on the narrow gauge; and the
compulsory restriction of so important a dimension as the width between
the rails has been a bar to any improvements of great magnitude or
comprehensive nature.
3. It gave, even with the overhanging carriage, the facility for obtaining
large wheels, and consequently diminishing the axle friction without

sacrifice of stability.
4. The greater width of base for the carriages to rest on gave increased
steadiness and smoothness of motion, particularly at high speeds. It was the
impulse given by the increase of speed and comfort obtained without
difficulty on the broad gauge, which had led to the chief improvements
introduced in railway travelling.
5. Greater safety was secured, particularly at high speed, from the
greater stability of position due to the wider base, producing increased
steadiness and diminishing the chance under exceptional circumstances of
the derangement of any part of the train.
6. While the broad gauge was but little more costly than the narrow, the
width of the works being determined not by the width of the rails, but by
the width of the carriages, and the extra cost of rolling stock being very
small,[61] the broad gauge could be worked more economically under
parallel circumstances than the narrow.
7. It gave the facility of using broader vehicles with equal steadiness, in
cases where the extra breadth would be useful, though the extra breadth was
by no means an essential part of the scheme.

The truth of these assertions, as establishing the superiority of the broad
gauge, was of course vehemently denied by the advocates of the narrow
gauge.
One objection urged by them, the inconveniences of the break of gauge,
has undoubtedly been proved by experience to be a very powerful one, so
powerful indeed as to compel the abandonment of the broad gauge on the
lines where any considerable quantity of goods traffic has to be carried in
competition with other companies.
Had Mr. Brunel’s original plan been carried out, and had the broad-
gauge companies taken possession of all the western portions of England,
and avoided extensions into the north, the points of contact would no doubt
have been so unimportant that no great inconvenience would have arisen, or
a few miles of double gauge would have removed any difficulty; but, under
the actual circumstances of the case, the Great Western Company were
forced to yield.

The advantages of the broad gauge were so much appreciated by the
districts it served, that its abandonment was viewed with considerable
displeasure, particularly in the neighbourhood of Birmingham; but the
inconvenience of double traffic arrangements far outweighed the
advantages derivable from the use of the broad gauge, to the limited extent
it could be applied on those outlying portions of the Great Western system.
For these reasons the Company came to the determination to work their
northern lines on the narrow gauge only.
The broad gauge is therefore now confined to the district for which it
was originally intended. Even in this district there are many points of
contact with the narrow gauge; but the inconveniences of break of gauge
are by no means so important as they were in the north, and do not, at
present at least, menace the continued existence of Mr. Brunel’s design.

CHAPTER VI.

THE ATMOSPHERIC SYSTEM.

A.D. 1840—1848. ÆTATIS 35—43.

PRELIMINARY OBSERVATIONS—THE SOUTH DEVON RAILWAY—
DESCRIPTION OF THE ATMOSPHERIC SYSTEM—HISTORY OF ITS
INTRODUCTION PRIOR TO 1844—REPORT BY MR. BRUNEL,
RECOMMENDING ITS ADOPTION ON THE SOUTH DEVON RAILWAY
(AUGUST 19, 1844)—EXAMINATION OF THIS REPORT—MR. BRUNEL’S
EVIDENCE BEFORE THE SELECT COMMITTEE ON ATMOSPHERIC
RAILWAYS, 1845—HISTORY OF THE APPLICATION OF THE SYSTEM
ON THE SOUTH DEVON RAILWAY, 1844-1848—REPORT ON STATE OF
WORKS (AUGUST 28, 1847)—REPORT ON CAUSES OF FAILURE
(AUGUST 19, 1848)—ABANDONMENT OF THE SYSTEM, SEPTEMBER
1848—NOTE—COMPARISON OF STATIONARY AND LOCOMOTIVE
POWER.

IN the year 1844 Mr. Brunel recommended the adoption of the Atmospheric
System of propulsion on the South Devon Railway, a line of 52 miles in
length, which he was then constructing between Exeter and Plymouth. This
system had, under the management of Messrs. Clegg and Samuda, been in
operation with success on the Dalkey line for some time before Mr. Brunel
adopted their apparatus on the South Devon Railway. After it had been in
use on the South Devon for about twelve months, it was abandoned, and the
railway worked throughout by locomotives.

It is therefore as important as it is interesting to examine the causes of
the failure of the Atmospheric System, and to consider the reasons which
induced Mr. Brunel in the first instance to adopt it, and afterwards to
recommend its abandonment.

Up to about the year 1843, the cost of railways, which was in a great
measure due to the conditions imposed by the limited capabilities of the
locomotive, had prevented their construction, except in cases where they

would secure a large traffic, and at the same time traverse what was then
considered a practicable country.
A curvature of one mile radius was regarded as the maximum generally
admissible on a line where high speeds were aimed at, and auxiliary
locomotives were required to work heavy gradients.
Nevertheless, by the growing wants of the public and the growing
boldness of engineers, the railway system was gradually being forced into
districts hitherto regarded as unsuitable for it; and no country was held to be
impracticable where the gradients could be surmounted by the inconvenient
and costly expedient of auxiliary power.

The south of Devon had for several years demanded railway
accommodation, and at the period now under review, Mr. Brunel projected
what was called the coast line. This line, while it best accommodated the
population of the district, passed through a very difficult country. If it was
to be constructed at a moderate cost, curves of a quarter of a mile radius had
to be admitted; and above 30 miles of its entire length traversed a district
involving the adoption of gradients steeper than had been elsewhere used
for such considerable distances. The Act for this railway was obtained in the
Session of 1844.

The South Devon Railway, on leaving Exeter, crosses the flat country on
the right bank of the river Exe, as far as Starcross, a village nearly opposite
to Exmouth. From this point it runs down to the coast and along the sea-
shore, by Dawlish, to Teignmouth; being protected by a sea-wall for the
greater part of the distance, and passing through several headlands by short
tunnels. Beyond Teignmouth it follows the left bank of the river Teign,
which it crosses a short distance before reaching the station at Newton
Abbott. The portion of the line from Exeter to Newton—21½ miles in
length—is very nearly level, the steep inclines for which the railway is
noted being west of Newton. Between Newton and Totness, for the first
mile and a half the line is almost level, and in the next two miles it rises 200
feet, with gradients of 1 in 100, 1 in 60, and nearly a mile of 1 in 43. At the
summit is a short tunnel; and thence the line descends 170 feet in a mile and
three-quarters, with gradients of 1 in 40 and 1 in 43 for about three-quarters
of a mile, and gradients of 1 in 57 and 1 in 88 for the rest of the incline. It

then runs with more moderate gradients and about a mile and a half of level
line to Totness.
From the valley of the Dart at Totness the line rises at once by a rapid
ascent of 350 feet in four miles and a half, with gradients varying from 1 in
48 to 1 in 90, more than a mile and a half averaging 1 in 50. Thence it runs,
with easy up and down gradients, for a distance of 12 miles along the skirts
of Dartmoor, crossing by lofty viaducts the deep valleys which penetrate the
moor. It then descends to Plympton, in the valley of the Plym, falling 273
feet in a little more than two miles, with a gradient of 1 in 42½. From
Plympton the line for two miles is level, and then rises on an incline of 1 in
80 for a mile and a half, and descends by a similar gradient into the
Plymouth station.
The main characteristics of the railway are that, while it traverses a very
heavy country, its principal changes of level are concentrated into four long
and steep inclines. These four inclines were intended to be worked by
auxiliary power.
Hitherto on gradients of unusual steepness a stationary engine with rope
traction had been generally regarded as the only available expedient; but the
special difficulties by which this system was encumbered rendered it
unsuitable for high-speed passenger traffic, and practically inapplicable to
an extended line. It had, however, been very successfully employed by Mr.
Robert Stephenson on the Blackwall Railway, a line of about 3¾ miles in
length.
Messrs. Clegg and Samuda, the projectors of the Atmospheric System,
which was another mode of using stationary power, had, previously to this
period, laboured to attract the attention and win the favourable opinion of
engineers and the general public.

It is desirable, before proceeding further, to give a brief description of
this system of traction, upon the merits of which distinguished engineers
entertained widely different opinions.
Between the two rails of the line of way was laid a cast-iron tube, which
on the Croydon and Dalkey railways and the completed or level portion of
the South Devon Railway was fifteen inches in diameter. On the inclines it
was proposed to use a twenty-two inch tube.

At intervals of about three miles along the line were erected stationary
engines, working large air-pumps, by means of which air could be
exhausted from the tube, and a partial vacuum created within it. A close-
fitting piston was placed in one end of the tube, and the air being exhausted
from it, the pressure of the external air on the surface of the piston which
was towards the open end of the tube forced the piston through the tube
towards the end where the air-pumps were working; so that if the piston
were connected with a carriage running on the rails, it would draw the
carriage with it. The connection between the piston and the carriage was
arranged by Messrs. Clegg and Samuda in the following way:[62] Along the
top of the tube was a slit about 2½ inches wide; this slit was closed by a
long flap of leather, which was strengthened with iron plates, and secured to
the tube at one side of the slit. One edge of the leather thus formed a
continuous hinge; the other edge, where it closed on the tube, was sealed
with a composition of grease, to render it air-tight. This flap was known by
the name of the longitudinal valve.
When the valve was closed, the air could be exhausted from the tube in
front of the piston, and a partial vacuum formed. Behind the piston, the air
being at atmospheric pressure both within and without the tube, there was
no objection to opening the longitudinal valve; and a bar, extending
downwards from the under side of the carriage, entered the slit obliquely
under the opened valve, and was connected to the rear end of a frame about
ten feet long, the front end of which carried the piston. To allow the bar to
pass along the slit, the valve was opened on its hinge, being pressed
upwards by a series of wheels carried by the moving piston-frame inside the
tube. The valve closed again after the passage of the train; and the tube was
ready to be exhausted in preparation for the passage of the next train.[63]
The Atmospheric System was first tried in 1840. An experimental tube
was laid down at Wormwood Scrubs on part of the short line now
incorporated into the West London Railway, and then known by the title of
the Bristol, Birmingham, and Thames Junction Railway. Its working was
the subject of eager discussion among engineers.
In 1842 Sir Frederic Smith, R.E., and Professor Barlow, under an order
from the Board of Trade, reported so favourably on the system with
reference to the proposal for its application on the Dalkey branch of the
Dublin and Kingstown Railway, that it was adopted there. In 1843 Mr.
(afterwards Sir William) Cubitt determined to employ it on the Croydon

Railway; and about the same time Mr. Robert Stephenson was desired by
the Directors of the Chester and Holyhead Railway to report on the
propriety of introducing it on that line.
Mr. Stephenson’s report was based on a series of experiments on the
working of the system at Dalkey. The view he took was adverse to its
adoption, not only on the Chester and Holyhead, but on almost every
railway whatsoever; and this on the ground that, though it was quite capable
of being developed into a practical working system, yet on lines with
ordinary gradients the atmospheric traction must be considerably more
costly than locomotive traction, and on steep gradients than rope traction; in
other words, that, as a mechanical appliance it was, though practicable, not
economical.
Mr. Stephenson’s report had no sooner appeared than the correctness of
his conclusions was disputed on his giving evidence before a Committee of
the House of Commons, in the spring of 1844, on the Croydon and Epsom
Railway Bill.

Mr. Brunel also was summoned as a witness. Previously to this time he
had taken a great interest in the various attempts which had been made to
introduce the Atmospheric System, and he had himself conducted
experiments at Wormwood Scrubs and at Dalkey. As early as July 1840 he
had considered its applicability to the Box Tunnel incline on the Great
Western Railway. He had also considered it in reference to various
projected lines; and in 1843 he recommended it for adoption in a long
tunnel on one of the steep inclines of the Genoa and Turin Railway, the
success of the system being then (he wrote) sufficient to justify its use on a
part of the line protected from weather. It was not, however, applied on this
railway.[64]
Mr. Brunel’s views at this time are indicated in the following letter:—
April 8, 1844.
Any part I have taken in examining into the system has been purely from the desire which I
always feel to forward good inventions; and when I have formed a decided opinion, no fear of the
consequences ever prevents my expressing it. My great anxiety, however, is to see a line of railway
and all its appurtenances made expressly for the Atmospheric System, and worked accordingly; until
this is done the results will be comparatively unsatisfactory.

Although unwilling to express general opinions, Mr. Brunel spoke
strongly before the Croydon and Epsom Railway Committee in favour of

the advantages of the Atmospheric System under certain circumstances, and
approved of its use on that line.
A few months later Mr. Brunel recommended the Directors of the South
Devon Railway Company to adopt the Atmospheric System, and they
resolved to act on his advice.
His report was as follows:—
August 19, 1844.
I have given much consideration to the question referred to me by you at your last meeting—
namely, that of the advantage of the application of the Atmospheric System to the South Devon
Railway.
The question is not new to me, as I have foreseen the possibility of its arising, and have
frequently considered it.
I shall assume, and I am not aware that it is disputed by anybody, that stationary power, if freed
from the weight and friction of any medium of communication, such as a rope, must be cheaper, is
more under command, and is susceptible of producing much higher speeds than locomotive power;
and when it is considered that for high speeds, such as sixty miles per hour, the locomotive engine
with its tender cannot weigh much less than half of the gross weight of the train, the advantage and
economy of dispensing with the necessity of putting this great weight also in motion will be evident.
I must assume also that as a means of applying stationary power the Atmospheric System has
been successful, and that, unless where under some very peculiar circumstances it is inapplicable, it
is a good economical mode of applying stationary power.
I am aware that this opinion is directly opposed to that of Mr. Robert Stephenson, who has
written and published an elaborate statement of experiments and calculations founded upon them, the
results of which support his opinion.
It does not seem to me that we can obtain the minute data required for the mathematical
investigation of such a question, and that such calculations, dependent as they are upon an unattained
precision in experiments, are as likely to lead you very far from the truth as not.
By the same mode M. Mallet and other French engineers have proved the success of the system;
and by the same mode of investigation Dr. Lardner arrived at all those results regarding steam
navigation and the speed to be attained on railways, which have since proved so erroneous.
Experience has led me to prefer what some may consider a more superficial, but what I should
call a more general and broader view, and more capable of embracing all the conditions of the
question—a practical view.
Having considered the subject for several years past, I have cautiously, and without any cause for
a favourable bias, formed an opinion which subsequent experiments at Dalkey have fully proved to
be correct; viz. that the mere mechanical difficulties can be overcome, and that the full effect of the
partial vacuum produced by an air-pump can be communicated, without any loss or friction worth
taking into consideration, to a piston attached to the train.
In this point of view the experiment at Dalkey has entirely succeeded. A system of machinery
which even at the first attempt works without interruption and constantly for many months, may be
considered practically to be free from any mechanical objection.
No locomotive line that I have been connected with has been equally free from accidents.
That which is true for one railway of two miles in length is equally true for a second or third,
although they may be placed the one at the end of the other; the chances of an accident are only in the
proportion of the number, or in other words, the length, a proportion which holds equally good with

locomotives, except that a locomotive may be affected by the distance it has previously run, while a
stationary engine and its pipes cannot in like manner be affected by the previous working of the
neighbouring engine and pipes.
In my opinion the Atmospheric System is, so far as any stationary power can be, as applicable to
a great length of line as it is to a short one.
Upon all these points I could advance many arguments and many proofs, but I shall content
myself with saying that, as a professional man, I express a decided opinion that, as a mechanical
contrivance, the Atmospheric apparatus has succeeded perfectly as an effective means of working
trains by stationary power, whether on long or short lines, at higher velocity and with less chance of
interruption than is now effected by locomotives.
I will now proceed to consider the question of the advantage of its application to the South
Devon Railway.
It will simplify the discussion of the question very much if it is considered as a comparison
between a double line worked by locomotives in the usual manner, and a single line of railway
worked by stationary power, the only peculiarity of the present case being that upon four separate
portions of the whole 52 miles stationary assistant power would under any circumstances have been
used, these four inclines forming together one-fifth of the whole distance.
It is necessary to consider it as a question of a single line on account of the expense, the cost of
the pipe for each line being about 3,500l. per mile.
An addition of 7,000l. per mile, or of about 330,000l., in the first construction could not be
counterbalanced by any adequate advantage in the saving in the works on the South Devon Railway,
and probably not by any subsequent economy or advantage in the working; but the system admits of
the working with a single line, without danger of collision, certainly with less than upon a double
locomotive line. And I believe also that, considering the absence of most of the causes of accidents,
there will even be less liability of interruption and less delay in the average resulting from accidents
than in the ordinary double locomotive railway.
By the modification of the gradients and by reducing the curves to 1,000 feet radius where any
great advantage can be gained by so doing, and by constructing the cuttings, embankments, tunnels,
and viaducts for a single line, a considerable saving may be effected in the first cost.
In the permanent way and ballasting, the reduction will be about one-half. I should propose to
make the rails about 52 lbs. weight and the timber 12 × 6; the quantity of ballast would probably be
rather more than half, but at the present prices of iron and timber the saving could not be less than
2,500l. per mile.
From a careful revision of the works generally, I consider that a reduction may be effected in the
following items, and to the amount specified in each, viz., ballasting gradients and curves:—

£ s. d.
Reduction in earth work 16,500 0 0
"in length of principal tunnel 14,000 0 0
30,500 0 0
Saving by single line.
Earthwork 25,000 0 0
Tunnels 11,500 0 0
Viaducts 15,000 0 0

Permanent way and ballast.
To allow for sidings, say 50 miles, 2,500l. 125,000 0 0
207,000 0 0
Per contra.
£
Pipe on 41½ miles[65] 138,500
Increase on inclined planes, 10½ miles 6,500 £ s. d.
145,000 0 0
Engines for the 41½ miles 35,000 0 0
Patent right, say 10,000 0 0
190,000 0 0
The difference in first cost therefore is 17,000 0 0
To this must however be added the cost of the
locomotive power, with its attendant expenses
of engine-houses, &c., which cannot, I think,
be put at less than 50,000 0 0
Making a saving of 67,000 0 0

I have not included in the expense of the Atmospheric apparatus that of the telegraph, because at
its present reduced cost of 160l. per mile I am convinced its use would repay the outlay in either case.
It would appear, then, that the line can be constructed and furnished with the moving power, in
working order, on the Atmospheric System, for something less than the construction only of the
railway fitted for the locomotive power, but without the engines; and that taking into consideration
the cost of locomotive power, a saving in first outlay may be effected of upwards of 60,000l.
But it is in the subsequent working that I believe the advantages will be most sensible.
In the first place, with the gradients and curves of the South Devon Railway between Newton and
Plymouth, a speed of thirty miles per hour would have been, for locomotives, a high speed, and under
unfavourable circumstances of weather and of load, it would probably have been found difficult and
expensive to have maintained even this; with the Atmospheric, and with the dimensions of pipes I
have assumed, a speed of forty to fifty miles may certainly be depended upon, and I have no doubt
that from twenty-five to thirty-five minutes may be saved in the journey.
Secondly, the cost of running a few additional trains so far as the power is concerned is so small,
the plant of engines, the attendance of engine-men, &c., remaining the same, that it may almost be
neglected in the calculations; so that short trains, or extra trains with more frequent departures,
adapted in every respect to the varying demands of the public, can be worked at a very moderate cost.
I have no doubt that a considerable augmentation of the general traffic will be thus effected, by
means which with locomotive engines would be very expensive, and frequently unattainable,
particularly as regards one class of short trains, whether for passenger or goods, which from the
inconvenience of working them by locomotives are hardly known—I refer to trains between the
intermediate stations.

By many means, which the easy command of a motive power at any time, at every part of a line,
must afford of accommodating the public, I believe the traffic may be increased.
It appears to me also that the quality of the travelling will be much improved; that we shall attain
greater speed, less noise and motion, and an absence of the coke dust, which is certainly still a great
nuisance; and an inducement will thus be held out to those (the majority of travellers) who travel
either solely for pleasure, or at least not from necessity, and who are mainly influenced by the degree
of comfort with which they can go from place to place.
Lastly, the average cost of working the trains will be much less than by locomotives.
With the gradients of the South Devon Railway, and assuming that not less than eight trains,
including mail and goods trains, running the whole distance, and certainly one short train running
half the distance, be the least number that would suffice, I think an annual saving of 8,000l. a year in
locomotive expenses, including allowance for depreciation of plant, may very safely be relied upon.
For all the reasons above quoted, I have no hesitation in taking upon myself the full and entire
responsibility of recommending the adoption of the Atmospheric System on the South Devon
Railway, and of recommending as a consequence that the line and works should be constructed for a
single line only.[66]

In this report Mr. Brunel rested his recommendation principally on two
assumptions, which he held to be indisputable—(1) That stationary power,
if freed from incumbrances such as the friction and dead weight of a rope,
was superior to locomotive power; and (2) That the Atmospheric System of
traction was theoretically a good and economical method of applying
stationary power, and that it was also a practical and working system, as had
been shown in its first and somewhat crude application at Dalkey.
The superiority of stationary as compared with locomotive power
depends on two principles—(a) That a given amount of power may be
supplied by a stationary engine at a less cost than if supplied by a
locomotive. (b) That the dead weight of a locomotive forms a large
proportion of the whole travelling load, and thus inherently involves a
proportionate waste of power—a waste which is enhanced by the steepness
of the gradients and the speed of the trains.
A detailed examination of these principles is given in the note to this
chapter.
It is there shown that at the time referred to stationary power could be
obtained for one farthing per horse-power per hour, while locomotive power
cost more than one penny per indicated horse-power per hour, the cost of
the locomotive power being more than four times that of the stationary
power. On a level line at a speed of 60 miles per hour, for each horse-power
usefully employed, a locomotive, in consequence of its own dead weight
and the friction of its machinery, is obliged to expend more than one and a

half horse-power; in this case, therefore, the useful work done costs nearly
seven times as much as if it had been performed by a stationary engine.
Again, on so moderate an ascent as one in 75, for each horse-power usefully
employed, the locomotive has to expend at 40 miles per hour more than two
horse-power, and at 60 miles per hour three horse-power; so that the useful
work done costs in the one case nearly ten times, in the other thirteen times,
as much as if it had been performed by a stationary engine.
This great advantage of stationary over locomotive power was a
sufficient justification for introducing a system which promised to realise it
to any considerable extent; although many difficulties might have to be
encountered.
As has been already stated, Mr. Brunel had satisfied himself that the
Atmospheric System was theoretically economical, and that its trial at
Dalkey had shown that it was practically free from mechanical objections.
Mr. Stephenson, indeed, had admitted that the mechanical details had been
brought to a remarkable degree of perfection; but this admission was not
any qualification of the radical difference of opinion which existed between
him and Mr. Brunel, to which Mr. Brunel drew attention in his report of
August 1844.
The subsequent abandonment of the Atmospheric System led many to
believe that Mr. Brunel had been rash in rejecting the detailed investigations
and conclusions of Mr. Stephenson, and that the adverse conclusions which
Mr. Brunel had refused to entertain were subsequently established.
But, in fact, the failure of the Atmospheric System was due to failure in
some of its mechanical details, and was not due to those inherent defects in
its principle which Mr. Stephenson in his report considered that his
experimental data had established.
Mr. Brunel’s opinions were again brought prominently into notice in the
evidence given by him before a Select Committee of the House of
Commons, which was appointed in the Session of 1845, in consequence of
the number of projected lines which it was proposed to work by the
Atmospheric System.
The following letter, written by Mr. Brunel to one of the members of the
Committee, explains what he considered to be his position at this time:—
April 3, 1845.

I am summoned to attend your Committee on Friday, and as it is known that I have expressed
opinions favourable to the Atmospheric System, and that I am actually applying it upon a line of
some length, it would be considered an absurd affectation, and would, moreover, be useless to
attempt, to avoid giving evidence when so called upon; but I am a most unwilling witness. I think it
rather hard upon a professional man, who wishes to be cautious and prudent, that he should be called
upon to express general opinions, which, if written even in the most studied and careful language,
cannot be so worded as to be applicable to every case that may hereafter arise, or to be proof against
the unfair and unscrupulous attack of the paid writers on these controversies. I mention these
difficulties, which I feel that you may make some allowances for, if my feelings should appear in my
evidence, or if that evidence should appear to fall very short of the opinions I am known to entertain,
and which I must entertain to induce me to apply the system extensively, as I am doing. I find it
difficult to define the points upon which it would be desirable to examine engineering witnesses, and
I really believe that, entering freshly upon the subject and feeling as one of the public, you are more
likely to elicit the useful points than one who, like myself, has been turning his whole attention
(lately, at least) solely to the mechanical construction. However, I enclose a copy of a letter I
addressed to a party interested in the patent, which refers to my opinions on the several points—
opinions, however, expressed without that caution to which I referred as so necessary.

(Enclosure.)
March 31, 1845.
I object very much to giving evidence upon the abstract point of the applicability of a particular
system, and thus furnishing general opinions which others are to apply as they may choose to
particular cases; and if I could, I would refuse to give evidence at all before the present Committee,
whatever might be the consequence to the promoters of the Atmospheric System. Circumstances,
however, render such a refusal impossible; but I am equally anxious not to be drawn into becoming
an advocate of a system.
When I gave evidence last year,[67] although it was then very much against my inclination, it
was in support of a particular case; and it was only incidentally that my opinion was advanced as to a
system. The evidence is now avowedly sought in support of a system, and I do not, as I before stated,
intend to become an advocate of this or any other system. I mention these my views to prevent
disappointment. If the following facts and opinions are likely to be of use to the Committee, I can
give evidence on them.
I made experiments upon the portion of railway laid on Wormwood Scrubs. These experiments
were made for my own private satisfaction, and not made public in any way.
They satisfied me of the mechanical practicability of the system.
In 1843 and 1844 I made several experiments upon the Dalkey railway.
The result of my observations and of those experiments is an opinion that the mechanical
difficulties attending the application of this system may be overcome, and the whole as a machine
made to work in a very perfect manner; that is, as a mechanical power for locomotion it will
generally, but not in every case, be more economical than what is strictly called locomotive power,
that high speeds may be more easily attained, that, from the absence of the locomotive engine, the
rails may be constructed and maintained in more perfect order, and as a consequence the carriages
may be constructed and worked in a more perfect manner, and so as to run more smoothly, and that in
all respects the travelling may be rendered more rapid, more luxurious, and more safe. As regards the
last, viz. safety, collisions may be rendered altogether impossible, or most remotely possible; while
all other sources of danger, now very small, may be almost entirely removed by the increased
perfection of the rails.

As regards first cost, a single line may be made to answer all the purposes of a double locomotive
line for most railways, except main lines in immediate connection with the metropolis, or forming
trunk lines for others with important branches not under the same control; and a single Atmospheric
line will generally cost as little, often less, including the working power, than a double locomotive
line without the engines. I am now constructing a line of 52 miles in length entirely for the
Atmospheric System. I already see many advantages to be attained in the setting out and constructing
of a railway, if originally designed for this system; the principal advantages can only be attained, and,
above all, the principal difficulties in the system can only be properly provided against, where the
line is originally designed for the system; the choice of gradients and curves and levels, the position,
and, above all, the arrangements of stations, will generally be totally different in the two systems, and
the difficulties to be avoided will equally differ.

It is unnecessary to give any extracts from Mr. Brunel’s evidence,[68] as
it only repeats the opinions and calculations embodied in his report of
August 1844.
The Committee, while they allowed that experience could alone
determine under what circumstances of traffic or of country the preference
to the Atmospheric or the Locomotive System should be given, reported
very strongly in favour of the general merits of the Atmospheric System.
As soon as it had been decided that the South Devon was to be
constructed as an Atmospheric line, the dimensions of the cuttings,
embankments, and tunnels were arranged for a single line, except on the
long incline west of Totness, and on that east of Plympton. In the
approaches to the principal summits the gradients were made somewhat
steeper, so as to reduce the excavations.
In December 1844, Mr. Brunel prepared a specification and drawing of a
steam-engine and vacuum pump, and a copy was sent to the most eminent
engine-builders, together with a letter inviting tenders for six pairs of
engines. The letter concluded as follows:—
Any party whose tenders may be accepted, shall, if required, furnish forthwith a more detailed
drawing and specification of the engines as they propose to furnish them; the specification and
drawing now sent being expressly made very general, in order that each manufacturer may, so far as
is consistent with the general requisites and conditions, adopt his own methods of construction, or
use any existing patterns.

The economical character of the engines which Mr. Brunel desired to
obtain is sufficiently indicated by the requirement that they were to be high-
pressure condensing engines, fitted with double-seated expansion valves,
and having boilers proved to 100 lbs. per square inch, and guaranteed to
work with safety valves loaded to 40 lbs. per square inch.

The tenders accepted were those of Messrs. Boulton and Watt, Messrs.
Rennie, and Messrs. Maudslay and Field.
Mr. Brunel left it to the contractors to prepare their designs without any
interference on his part, deeming it best to rely on their unfettered
judgment.
The task of manufacturing and fitting the cast-iron tube was one of some
difficulty, the longitudinal slit allowing of considerable distortion in the
casting. This work was undertaken by Mr. George Hennett, by the aid of a
set of very effective tools devised by Mr. T. R. Guppy.
The tubes were supplied at the rate of one mile per week, and by the
middle of 1846 nearly the whole line was laid to Newton, and the valve was
ready to be fixed.
In the autumn of 1846, Mr. Joseph Samuda went to Dawlish, taking with
him a staff of assistants trained in the working of the system at Croydon;
and every effort was made to advance the completion of the engines and the
other parts of the apparatus.
Owing, however, to vexatious delays in the erection of the engine-houses
and engines, it was not until the commencement of 1847 that a piston-
carriage was able to traverse the first six miles out of Exeter. And, though
repeated experimental trains continued to be run, no passengers had been
conveyed by Atmospheric trains prior to the general meeting of the
shareholders, at the end of August. Mr. Brunel’s report on this occasion was
as follows:—
August 27, 1847.
It is a subject of great regret, and to no one more than to myself, that we have as yet been unable
to open any portion of the line to the public with the Atmospheric apparatus, although a considerable
distance has for some months been in a state to admit of frequent experiments being made upon it.
This delay has arisen principally, if not entirely, in that part of the whole system which it might have
been expected would have been the least exposed to it—namely, the construction and completion of
the steam-engines.
It is due to Mr. Samuda that I should say that, so far as regards the mere pipe and valve, and other
details which may be said to constitute the Atmospheric apparatus, we might long since have
commenced. But the engines, although designed without any interference with their plans, and
furnished by the best makers of the country, and although differing so slightly from the ordinary
construction of steam-engines, have proved sources of continued and most vexatious delays, both in
the unexpected length of time occupied originally in their erection, and in subsequent correction of
defects in minor parts. While the engines were imperfect, it would not only have been unwise to have
commenced working the line, even had it been practicable, but the frequent interruptions to the
continuous working of all the engines rendered it impossible to complete and test the different
portions of the Atmospheric apparatus. There are still some defects to be remedied in one or two of

the engines, and I am using every endeavour, by persuasion and by every other means in my power,
to urge on the manufacturers in their work of completion. Within the last week or two only have we
been able to work at all continuously between Exeter and Teignmouth, so as to have the opportunity
of trying the different parts, and getting the various details requisite for actually working trains tested
and brought to sufficient perfection to ensure efficiency and regularity.
Since the beginning of last week, however, four trains per day have been run regularly, stopping
at the stations, and keeping their time as if working for traffic. The tube and valve appear in good
order, and the whole has worked well, but the running in this manner can alone show the deficiencies
which may still exist in the details necessary for stopping, and starting quickly from the stations, and
all the other minor operations incidental to working the traffic in the ordinary course; and, until all
these arrangements are completed, and the engines in more perfect order, I think it would be much
better to defer at least the substitution of the Atmospheric for the locomotive working. Trains, in
addition to those now running may perhaps be advantageously worked for the public, after a further
short continuance of the present practising.
The two engines completing the number to Newton are nearly ready for trial, and it is to be
presumed that, after the experience of the past, the makers will be enabled to put them at once into an
efficient state.
The delays and difficulties attending the bringing into operation the Atmospheric System upon
this portion of the railway have been beyond all anticipation, and beyond what any previous
experience would have justified anybody in anticipating. The difficulties have all been seriously
aggravated by the necessity (consequent, certainly, upon the original delays) of working the line with
locomotives during the construction and completion of the Atmospheric apparatus. Not only has the
constant occupation of the line interfered with the progress of the work, but it has been necessary to
devise all the arrangements so as to admit stations, sidings, and line being worked either by
locomotive or by Atmospheric in succession, or even at the same time.
These difficulties, added to those always consequent upon the introduction of any new system,
have been most wearying and incessant, and I am not surprised that the public and the proprietors
should have been impatient. I trust the ultimate result will remove any grounds for disappointment.

The stress of personal anxiety and personal fatigue, experienced by Mr.
Brunel and by all who were engaged in the work, was very severe, and
continued so to the end. Not only was the progress in the completion of the
work slow, but in spite of every exertion the results were incessantly marred
by unfortunate contingencies which involved further delay, discouragement,
and expenditure. Moreover, the reaction which followed the railway mania
had set in; calls were ill responded to, and great difficulty was experienced
in raising the money requisite for the completion of the line.
Under these circumstances it was resolved, on September 1, not to incur
any new expenses in relation to the Atmospheric System beyond Totness,
and to limit any expenditure already contracted for, until its working
between Exeter and Totness had been fairly tried, except to provide
assistant power up the two inclines.
On September 8 the Atmospheric trains began to take their share in the
passenger duty of the line, four trains running each way daily; and, except

when occasional mishaps caused delay, the new mode of traction was
almost universally approved of. The motion of the train, relieved of the
impulsive action of the locomotive, was singularly smooth and agreeable;
and the passengers were freed from the annoyance of coke dust and the
sulphureous smell from the engine chimney.
In other respects the record of progress is but a chequered one, and
exhibits, in spite of great and able efforts and brightening intervals of
occasional improvement, indications of growing difficulties deepening into
ultimate defeat.
In examining the chronicle of events which correspondence and
memoranda supply, it is inevitable that references to failure and disaster
should be found relatively in far greater abundance than records of success;
and this for the simple reason that there was at that time great use in taking
note of the unfavourable incidents that occurred, almost none in mentioning
successful work.
There is therefore some danger of falling into a mood of unjust
depreciation, such as Mr. Brunel had in energetic terms urged the Directors
to guard themselves against. He protested against their requiring (as they
once intended to do)—
continuous and detailed reports—if true and honest, of course containing nothing but accounts of
mishaps—of a system which (he says) we are struggling to render perfect. Why, a daily account of
our locomotive mishaps would ruin the locomotive system, if it were new! I will undertake to say
that the mishaps of yesterday or to-day on the Great Western Railway were as great as that of
Tuesday on the South Devon.

The Atmospheric System was vaguely credited with every delay which a
train had experienced in any part of its journey; though, in point of fact, a
large proportion of these delays was really chargeable to that part of the
journey which was performed with locomotives. It often happened that time
thus lost was made up on the Atmospheric part of the line, as is shown by a
record of the working, which is still extant. In the week, September 20-25,
1847, it appears that the Atmospheric trains are chargeable with a delay of
28 minutes in all; while delays due to the late arrival of the locomotive
trains, amounting in all to 62 minutes, were made up by the extra speed
attainable on the Atmospheric part of the line.
Not unfrequently, however, casualties occurred; due indeed to
remediable causes, but yet of discouraging aspect in themselves, and
deriving additional weight from the manner in which they reacted on the

cost of working. Such, for instance, were the frequent and occasionally very
serious breakages in essential parts of the pumping-engines. Again, the
cupped leathers of the travelling-piston, which made it air-tight, were often
destroyed while it was passing the various inlet and outlet valves.
Improvements in the valves were introduced to meet this difficulty; but the
remedy could not be applied at once throughout the line, and much
inconvenience was thus experienced, and a considerable expense incurred.
Another source of inconvenience was the water which at times accumulated
within the tube.

In many respects the results which had been calculated on were realised,
and the new arrangements necessary to the working of the system were
successfully brought into operation.
The speed of the trains corresponded fully with the degree of vacuum
obtained; that is to say, the train resistances proved to be what had been
anticipated.[69]
After the trial of a great variety of air-pump valves, a form was adopted
which was found to answer exceedingly well.[70]
In the Atmospheric tube, the system of self-acting inlet and outlet valves,
by which the piston was enabled to leave the tube on approaching a station
and enter it again on recommencing its journey, were, on the whole,
successfully adapted to their duty.
Again, an arrangement for starting the train rapidly from the station,
without the help of horses or of locomotives, had been brought practically
into operation. This arrangement consisted of a short auxiliary vacuum tube
containing a piston which could be connected with the train by means of a
tow-rope, and thus draw it along till the piston of the piston carriage entered
the main Atmospheric tube. Some accidents at first occurred in using this
apparatus, but its defects were after a time removed; and it is hardly to be
doubted that the various minor difficulties of the Atmospheric System could
soon have been effectually mastered.

It now remains to show how it was that, in spite of much that was
hopeful, a vigorously sustained contest ended in defeat, instead of being
prolonged into victory.

In working the Atmospheric System on the South Devon Railway grave
difficulties were throughout encountered, for which to the last only
imperfect remedies could be found.
As regards the power consumed, the engines of each pumping station
worked up to about 236 indicated horse-power, and their regulated duty for
each train, including the anticipatory pumping, was equivalent to 5·5
minutes of work for every mile of the length of tube they had to exhaust. As
the running speed averaged 40 miles per hour, or a mile in 1·5 minutes, the
236 horse-power during the 5·5 minutes of pumping must be regarded as
equivalent to 865 horse-power during the actual passage of the train. Now,
making full allowance for piston friction and extra friction on curves, for
the power expended in getting up speed, for the excess of air-pump
resistance due to the changes of temperature experienced by the air under
exhaustion, and even for the very large actual amount of friction in the
engines employed, the work done should have been represented by an
expenditure of 240 horse-power during the passage of the train. If to this is
added an allowance for leakage, such as the experiments at Dalkey
indicated would be amply sufficient with the longitudinal valve in good
condition, it may be said that Mr. Brunel had a right to expect that the duty
would be performed with an expenditure of 300 horse-power; whereas it
actually required 865 horse-power, or nearly three times the amount.
The explanation of this waste is simple.
Serious and unexpected causes of failure developed themselves in the
longitudinal valve, and led to an excessive amount of leakage. A great part
of the normal duty of the engines was, as has been stated, to exhaust the
tube previous to the entry of the train; and when, owing to leakage, the
amount of air to be so pumped out was greatly increased, it became
necessary that the operation should be commenced much earlier. There was
thus a longer time during which the leakage could take place, and a still
greater amount of air to be pumped out. It therefore followed that a large
increase of leakage involved waste of power in an enormously increased
proportion.
The length of time occupied by the anticipatory pumping was often
increased by the difficulty of arranging proper telegraphic communication
on the South Devon Railway, and by the absence of it on the Bristol and
Exeter Railway. The Electric Telegraph was in its infancy, and though Mr.

Brunel had been the first to apply it in connection with railways, namely,
between London and Slough on the Great Western Railway in the year
1839, it was not brought into perfect working order on the South Devon
Railway till the Atmospheric System was on the point of being abandoned.
The result of the defects in the telegraph was that, when a train was late,
warning was not received at the several engine-houses;[71] and thus, when
this was the case, the pumping-engines which had been started at the right
interval of time before the train was due, had to be kept at work for a
needlessly long period pumping out the air, which was all the while leaking
in through the deteriorated valve. This inefficiency of the telegraphic
apparatus would have been of trifling importance but for the defects of the
valve. Had the valve been as perfect as it was expected to be, the vacuum,
after it had been formed, could have been maintained by an expenditure of
power very moderate in comparison with that which was actually required.
As regards the relative cost of the power consumed, it appears that,
owing to imperfections in the engines, their expenditure of fuel per
indicated horse-power was more than double that of the best of the Cornish
pumping-engines, to which they were analogous; while the cost of working
was more than three times as great.
The defects in the engines were for the most part such as might have
been remedied; and this would have been done, had not the excessive duty
imposed on them by the leakage of the longitudinal valve prevented their
being stopped for repairs and alterations. In this way the defects of the
different parts of the apparatus mutually aggravated each other.
It appears then that, chiefly owing to the defective longitudinal valve, the
engines were expending nearly three times the power which they should
have done for a given tractive duty, according to previous experience, and
the results obtained on the Dalkey line, and that they cost per horse-power
at least three times as much as was expected.
The cost of traction, nearly nine times as much as had been calculated
on, was between two and a half and three times what it would have been
with locomotive power; and this was on a level part of the line, where the
comparative advantages of the Atmospheric System were not exhibited as
they would have been in the part which had steep gradients.
The imperfections of the longitudinal valve have now to be described.
By its condition the Atmospheric System had to stand or fall. With an

efficient valve, the defects of the other parts of the apparatus would have
been of minor importance, and time would have been given for remedying
them. When the leakage became considerable, the defects of the telegraph
and the defects of the engines alike assumed a formidable aspect.
The failure of the valve was due, partly to the composition which was
used to seal the joint where it opened, and partly to the material of which
the valve consisted. The difficulty of obtaining a suitable composition was
the first which had to be encountered. On the South Devon a lime soap was
eventually found to answer the purpose well. Its surface, however, from
exposure to light and air, formed into a hard skin; and to remedy this a
thinner and more fluid material, a compound of cod-oil and soap, was laid
on to keep it soft. This answered satisfactorily, but it required frequent
renewal, as it was apt to be drawn into the tube by the rush of air when the
valve was opened. The renewal of the various compositions, and the careful
examination and repair which the valve constantly required, was a cause of
great anxiety and expense.
But in the materials of the valve lay the source of the more serious
difficulty.
The ready affinity of leather for oil and grease, and its suppleness and
closeness of grain when saturated with substances of that nature, had long
been known and utilised. It had not been anticipated how readily, with air-
pressure on one side and a partial vacuum on the other, the oily matters with
which the leather was charged would escape from it, especially in the
presence of water. Although, while the leather was saturated with water, the
valve was remarkably air-tight; when frost supervened the water became
frozen, and gave a fatal stubbornness of texture, which rendered the valve
incapable of closing properly. Again, in long-continued drought the leather
became intractable from its dryness; and the stiffening, whether from frost
or drought, rendered it liable to be torn. An immediate application of seal-
oil penetrated the leather, and relaxed its stiffness; but the remedy often
could not be applied in time, and, moreover, was expensive.
A still more grave defect was all the while becoming matured, and was
undermining every hope that a suitable dressing could be discovered, and
that the longitudinal valve might be made perfect.
Under the joint action of water in the leather, and of the affinity of iron
for tannin—and on the enduring presence of tannin within its texture the

consistency of leather depends—a destructive decomposition had long been
at work; the oxide, established in the iron plates of the valve by continued
contact with damp leather, had been steadily abstracting the tannin; thus the
leather had become converted into an ink-stained and comparatively
decomposed tissue. Large portions of it became torn, and incurably
pervious to air.
It was not until early in June 1848 that Mr. Brunel discovered the
condition which the valve had assumed. He then instituted a careful
examination throughout the line, and the extent of the disorder was realised.
The state of things which existed when this discovery was made in effect
involved the renewal of the valve the whole distance from Exeter to
Newton; so that, as the cost of the valve was 1,160l. per mile, an immediate
outlay of some 25,000l. became essential to the maintenance of the system,
and this at the time when the real difficulties of the valve question had
become most apparent. By galvanising the iron plates of the valve the
mutually destructive action of the iron and the leather might have been
prevented; but a remedy was also required for the other serious defect
which leather, as the material of the valve, was found to exhibit, namely, its
tendency to become permeable to air after long-continued use under air-
pressure, owing to the inward escape of the material with which it had been
dressed.
These difficulties were not only such as had not been anticipated, but
such as no one was justified in anticipating.

It now became necessary for Mr. Brunel to consider what course, under
the circumstances, it was most advisable for the Company to adopt.
A Committee of the Board was appointed to examine the whole
question; and, at their desire, Mr. Brunel made a report upon it, which was
as follows:—
August 19, 1848.
You have called upon me to report to you upon the present state of the Atmospheric apparatus,
and particularly upon the circumstances connected with the partial destruction of the longitudinal
valve which has lately occurred, and the probability of remedying this serious defect, and of keeping
the valve in repair and in good working order.
Such a report involves necessarily the consideration of the whole question of our experience of
the working of the Atmospheric System; because, to arrive at any clear appreciation of the present
state of the apparatus, I must refer to the circumstances which have affected our working up to the

present time, and particularly to the several difficulties which we have had to encounter and their
effects.
The first difficulty, and one which was as unexpected as it was serious, was in the working of our
stationary engines. Upon the efficiency of these machines must of course ultimately depend the
economy and efficiency of the working of the whole system, however perfect in itself might be the
Atmospheric apparatus. Accordingly, great precautions were taken—precautions which I still think
such as to justify the expectation that we should secure the best engines that could be made.
The three first manufacturers of the day were employed—Messrs. Maudslay (who had had some
experience in this particular branch, having made the engines for the Croydon railway), Messrs.
Boulton and Watts, and Messrs. Rennie. They prepared their own designs; and I know that they each
bestowed much thought in the preparation of these designs, and took considerable interest in the
results.
Mr. Samuda, a man of considerable mechanical abilities, having all the experience that could be
had upon the subject, and deeply interested in the success of the engines, was also employed to
superintend their manufacture.
Notwithstanding all these precautions, notwithstanding excellent workmanship, these engines
have not, on the whole, proved successful; none of them have as yet worked very economically, and
some are very extravagant in the consumption of fuel, burning nearly double the quantity of others,
while the average is very considerably more than it ought to be.
The apparent causes of this excess are various in the different engines, but all resulting more or
less apparently from the want of experience in this particular application of power, and from the
circumstance of the form of the engines being somewhat novel, and involving slight differences in
the proportion and arrangement of the parts; and the consumption of steam being greater than was
calculated upon, it has been obtained by a more wasteful expenditure of fuel, and the evil has been
aggravated.
The difficulty of remedying this state of things has been increased by the consequence of defects
in the Atmospheric apparatus, which, causing a much greater demand upon the working of the
engines, has delayed, or has entirely prevented, our throwing an engine out of work, to introduce the
requisite improvements.
Still, so far as this defect in the engines is concerned, there is no doubt that it is susceptible of
considerable, if not complete remedy, and that a reduction of one-third may be effected in the
consumption of fuel.
In the Atmospheric apparatus itself our difficulties have been more numerous.
We have suffered from extreme cold, particularly when it followed quickly upon wet.
We have suffered from extreme heat, and also from heavy falls of rain. These difficulties have in
turn been encountered and gradually overcome, and I think the effects of all these causes upon a
valve in good condition may now be obviated, if not entirely, yet so much so as to render their
operation unimportant.
The same remedy applies to all three—keeping the leather of the valve oiled and varnished, and
rendering it impervious to the water, which otherwise soaks through it in wet weather, or which
freezes in it in cold, rendering it too stiff to shut down; and the same precaution prevents the leather
being dried up and shrivelled by the heat; for this, and not the melting of the composition, is the
principal inconvenience resulting from heat. A little water spread on the valve from a tank in the
piston-carriage has also been found to be useful in very dry weather, showing that the dryness, and
not the heat, was the cause of leakage; but a new difficulty has arisen, and a new defect has been
discovered, one much more serious in its extent and its possible consequences, and one which
renders the operation of each of the previously mentioned causes of difficulty much more powerful
and mischievous.

Within the last few months, but more particularly during the dry weather of last May and June, a
considerable extent of longitudinal valve failed by the tearing of the leather, at the joints between the
plates; the leather first partially cracked at these points, which causes a considerable leakage,
particularly in dry weather; after a time it tears completely through, and that part of the valve is
destroyed, and requires to be replaced.
A considerable extent has thus been replaced, but the whole of the valve is more or less defective
from this cause; the amount of leakage is considerable, and the working altogether inefficient. I have
examined carefully portions of the valve that have been removed, and I find that at the part which has
given way the texture of the leather seems to be destroyed—it is black, and has evidently been acted
upon by the iron of the plates.
Upon some parts of the line the injury seems to be more general than upon others; but it is very
difficult to examine the valve in place, so as to form any correct opinion of the extent of the evil.
As regards the cause of this defect, Mr. Samuda, who under his contract is at present liable for
the repair of the valve, urges that the valve was kept for a length of time in cases after it was
delivered to the Company, and that, exposed to damp, and the oil in the leather not being renewed on
the surface, the iron may have rusted, and the leather have been injured; and he refers to instances
lately observed, in which valves taken out of the top of a case which had been exposed to wet do
show similar signs of injury.
Supposing, however, this assumption to be correct, it would not seem to affect the question of his
liability. He suggests also, as a cause, that the valve remained for a length of time in place without
been used and even worked over by locomotive engines, which prevented its being properly oiled
and attended to; that the evil has been aggravated by an attempt to reduce too much the use of oil to
the leather; and, lastly, that the piston-gear has been allowed to get out of adjustment, so that the
leather of the valve has been strained.
I shall not, however, here enter into the discussion of this question of liability, but confine myself
to the consideration of the evil, and the possibility of remedying it.
Of the extent of the evil, for the reason I have given, it is impossible to form any accurate
opinion; it is impossible, therefore, to say that it does not extend more or less over the whole
distance, excepting, of course, that which has been already replaced. That which is injured cannot be
repaired in place, but must be removed, and the remedy can only be applied in the new valve.
It is quite possible that a valve made in the same manner as the present, if properly attended to
from the first, and with our present experience, might not be subject to this destruction, and Mr.
Samuda states that such is the case at Dalkey; but I do not think that I could rely upon this result. By
painting, but, better still, by zincing or galvanising the iron plates, and making them overlap a short
distance, both the chemical and the mechanical action of the plate upon the leather appears to be
prevented, and I believe, therefore, that this evil may be remedied at a small increased cost in any
new or repaired valve that might be laid down: but of the existing valve I can say no more than I have
done. It is not now in good working condition, and I see no immediate prospect of its being rendered
so.
From the foregoing observations, it will be evident that I cannot consider the result of our
experience of the working between Exeter and Newton such as to induce one to recommend the
extension of the system.
I believe that if the longitudinal valve were restored, the working expenses might be immensely
reduced; that the quantity of fuel consumed which is the great item of expense, may be diminished by
one-third; that the price of the fuel, which now costs 18s. per ton at the engine-houses, ought to be
reduced at least 12 per cent.; and that the total cost may thus be brought down to a moderate amount,
such as I had originally calculated upon. But the cost of construction has far exceeded our
expectations, and the difficulties of working a system so totally different from that to which
everybody, traveller as well as workmen, is accustomed, have proved too great; and therefore,

although, no doubt, after some further trial, great reductions may be effected in the cost of working
the portion now laid, I cannot anticipate the possibility of any inducement to continue the system
beyond Newton.
With respect to the future working of the apparatus between Exeter and Newton, I feel in great
difficulty as to expressing any opinion, seeing that a very large expense has been incurred, and
believing, as I do, that the cost of working may be so very much reduced; but that reduction can only
be effected by the almost entire renewal of the valve, and by some expenditure in the engines. And
unless Mr. Samuda or the patentees undertake the first, and extend considerably the period during
which they would maintain it in repair, and unless they can offer some guarantee for the efficiency of
that valve, I fear that the Company would not be justified in taking that upon themselves, or incurring
the expense attending the alteration of the engines.
I believe that for the inclined planes, as an assistant power, the apparatus will be found applicable
and efficient; and as the engines and the pipes are nearly ready at Dainton, it may be found desirable
to try it there, provided a satisfactory arrangement can be entered into for the maintenance and
efficiency of the valve.
I have not referred to our great disappointment in not obtaining the assistance of the telegraph in
the working of the engines, and the greatly increased consumption of coal consequent upon the
working the engines unnecessarily, because this evil is now nearly removed; but some further
reductions may still be made by using the telegraph by night as well as day, which has not yet been in
our power to do, but which I trust will be commenced this week.

The Committee to whom this report was made, and who had been also in
constant communication with Mr. Brunel, placed the result of their
investigation before the Board. The Directors, after carefully considering
the information given them, reported as follows:—
Your Directors, without pronouncing any judgment as to the ultimate success of the Atmospheric
System, and while they are prepared to afford to the patentees and other parties interested in it the use
of their machinery for continuing their own experiments, have arrived at the conclusion, with the
entire concurrence and on the recommendation of Mr. Brunel, that it is expedient for them to suspend
the use of the Atmospheric System until the same shall be made efficient at the expense of the
patentees and Mr. Samuda.

At the meeting in August, the proprietors adopted the Directors’ report,
and the line was worked throughout by locomotives on and after September
9.
In the following November Mr. Thomas Gill, the chairman of the Board
of Directors, published an ‘Address to the Proprietors,’ in which he strongly
deprecated the abandonment of the Atmospheric System, and proposed that
the Company should embark on a further experiment. Mr. Gill’s pamphlet
was referred to three of the Directors, Mr. Thomas Woollcombe, Mr.
Charles Russell, and Mr. James Wentworth Buller. With Mr. Brunel’s
assistance, and to a great extent from memoranda written by him, they
prepared a statement which went very fully into all the points raised by Mr.
Gill.

After combating Mr. Gill’s propositions, they observe:—
Of the two men who are most deeply concerned in the further trial of any reasonable experiment
to perfect the Atmospheric System, we find that one, Mr. Brunel, disapproves of the proposal for the
purpose as insufficient and unsatisfactory; the other, Mr. Samuda, had not sufficient confidence in the
result, or in Mr. Gill’s estimates for its accomplishment, to offer the only security which would
justify the Company in endeavouring to effect it.

In conclusion they express an opinion that the suspension of the
Atmospheric System in the previous September was a prudent and
necessary step, and that nothing had since occurred to justify its resumption.
The proprietors adopted the view taken by the Committee, and no further
attempt was made to work the railway on the Atmospheric System.
Under these circumstances, it cannot be a matter of surprise that Mr.
Brunel was much censured for having advised the South Devon Railway
Company to work their line on the Atmospheric System.
The reasons which led him to recommend the use of the Atmospheric
System on the South Devon, and the causes of its failure, have been very
fully described, and it has been also shown that the most important of these
were the defects of the pumping-engines, and the deterioration of the
longitudinal valve.
When the formidable character of these difficulties had fully declared
itself, the South Devon Railway Company were not in a position to spend
any more money upon a system which, as the event had proved, was, in one
of its most important details, still in the experimental stage.
There can be no doubt that the abandonment of the Atmospheric System
was the wisest step which, under the circumstances, could be adopted; and
it was recommended to the Directors by Mr. Brunel with a simple and self-
sacrificing disregard of every consideration except that which was always
paramount with him, the interests of those by whom he was employed.[72]

NOTE (p. 143).
Comparison of Stationary and Locomotive Power.
In order clearly to set forth the reasons which justify the statement made
by Mr. Brunel,[73] that stationary power if freed from the weight and friction
of any medium of communication, such as a rope, must be cheaper than
locomotive power, it is desirable to consider, (1) the waste of power which

arises from the locomotive having to move itself as well as the train; and (2)
the excess of cost at which a given power was supplied by a locomotive, as
compared with that at which it could have been supplied by a stationary
engine.
On the first point, the best information can be obtained from experiments
made by Mr. Daniel Gooch during the gauge controversy. The results are
very suitable for use in the present investigation, as the South Devon was to
be a broad-gauge railway. Moreover, as the broad-gauge engine with which
these experiments were tried was one of a class more powerful for their
weight not only than the contemporary narrow-gauge engine, but also than
the engines Mr. Brunel had experience of when he wrote his report three
years previously, the results may be considered to represent very favourably
the then existing case for the locomotives.
The engine employed in the experiments weighed, with its tender, about
fifty tons. The maximum power it was capable of delivering by the pressure
of steam in its cylinders was represented as a tractive force of 4,900 lbs. at a
speed of 60 miles an hour, equivalent to 784 indicated horse-power; and at
40 miles an hour 5,200 lbs., equivalent to 555 indicated horse-power.
It is next to be considered how this power would, when running at the
speeds mentioned, be employed in overcoming the elements of resistance.
These are:—
(1) The working friction of the machinery.
(2) The rolling resistance of the engine and tender.
(3) The air resistance due to the engine frontage.

(4) The rolling resistance of the train.
(5) The air resistance on the portion of the train unprotected by the
tender.
(6) The resistance due to gradient.
The following symbols and quantities may be conveniently made
use of to denote the various terms of the equation between force
and resistance.
Total available tractive force in lbs. F
Weight of engine and tender (superfluous load) in tons 50
Weight of train (useful load) in tons W

The sum of the resistances of machinery, rolling resistance,
R
and air resistance of engine and tender
Rolling resistance of train in lbs. per ton K
Gradient G
Speed in miles per hour V
Resistance of air (according to the received empirical formula)

1
= (frontage area) × V2
400

Frontage area of train in square feet 63
Frontage area of portion of train unprotected by the tender,
24
in square feet
For a locomotive train therefore
24
F = R + WK + V2 + (50 + W) 2240 G.
400
For a system that dispenses with the locomotive
63
Tractive force = WK + V2 + W 2240 G.
400
Therefore
W (K + 2240 G) + ·1575 V2
= the useful tractive force, and
R + 112000 G - ·0975 V2
= the tractive force wasted by the use of the locomotive.
Therefore
F={R + 112000 G-·0975 V2} + {W (K + 2240 G) +·1575 V2}
and the useful load
(F- R - 112000 G - ·06 V2)
W
K + 2240 G.
The values which Mr. Gooch’s experiments give for the two selected
speeds are as follows[74]:—

Miles per Hour R (lbs.) K (lbs. per ton) F (lbs.)
40 1500 12·5 5200
60 2100 18·6 4900

Using these values, the results in the following table are obtained, being
the conditions appropriate to the two speeds at successive ascending
gradients:—

Super- Ratio of
Useful Gross
Miles fluous Useful Waste Gross Waste to
Ascending Load Load
per Load Horse- Horse- Horse- Useful
Gradient in in
Hour in power power power Horse-
tons tons
tons power
0 288 50 338 411 144 555 ·35
1/200 128 50 178 352 203 555 ·58
1/100 71 50 121 292 263 555 ·90
40-{ 1/75 50 50 100 252 303 555 1·20
1/50 23·8 50 73·8 173 382 555 2·21
1/40 11·7 50 61·7 113 442 555 3·91
1/36·3 7 50 57 82 473 555 5·77
0 139 50 189 504 280 784 ·56
1/200 68 50 118 415 369 784 ·89
60-{ 1/100 35·7 50 85·7 325 459 784 1·41
1/75 22·5 50 72·5 265 519 784 1·96
1/52·3 7 50 57 160 624 784 3·90

Thus, on a level line, the engine, working up to 555 horse-power, could
just draw 288 tons of train at the rate of 40 miles per hour, wasting on its
own resistance only one-third of the power usefully employed on the train;
but when the speed was increased to 60 miles per hour, it could not, though
working up to 784 horse-power, draw more than 139 tons of train, wasting
on its own resistance more than half the power usefully employed on the
train. And again, at 40 miles per hour, though, as just stated, it could draw
on the level 288 tons, it could only draw 24 tons of useful load at that speed

up 1 in 50; while at 60 miles per hour, though it could draw, as stated, 139
tons of train on the level, it could only draw 23 tons of useful load up 1 in
75; and at the respective speeds of 40 and 60 miles per hour, it could only
take one carriage (7 tons) up the respective gradients of 1 in 36, and 1 in 52.
Hence to maintain a minimum speed of 40 miles per hour with
locomotive power on a line with long gradients of 1 in 40 involved on those
parts of the line a wasted power of nearly 4 times that usefully employed;
and if a minimum limit of 60 miles per hour were contemplated, a
locomotive of the most powerful class in existence three years subsequent
to Mr. Brunel’s report advising the adoption of the Atmospheric System
would only have been able to take a single carriage up an incline of 1 in 52.
So heavily at high speeds on steep gradients is the performance of a
locomotive taxed by the resistance due to its own dead weight.[75]

A comparison has now to be made between the cost of power as
developed by a locomotive and as developed by a stationary engine.
From the well-known experiments made for the information of the
Gauge Commissioners in December 1845, taking the high speed trials as
the basis of calculation, it appears that 4·5 lbs. of coke per horse-power per
hour may be taken as the average consumption of the engine.[76]
It will be well, however, to allow for the improvement which was at the
time anticipated in locomotive working, and to assume an expenditure of 4
lbs. of coke per indicated horse-power per hour, as representing the case
then for the locomotive engine.
Coke may be taken to have at that time cost 21s. a ton, or ·0094s. per lb.
Moreover, a careful analysis of the Great Western Railway half-yearly
reports, for 1844 and 1845, shows that for every shilling expended in coke,
1·44 shillings were expended on the average in wages, oil and waste,
repairs, etc.
Putting the results together, it appears that for each single indicated
horse-power delivered by a high-speed locomotive, the cost per hour was
0·0915s. or 1·098d.; that is to say, about 11/10 d. per hour.
Let this now be compared with the cost per horse-power per hour at
which the best Cornish pumping engines had long been known to perform
the work. This comparison is manifestly a rational one—with reference to
the kindred employment of engine power in atmospheric pumping-engines.

The performances of nearly all the pumping-engines in Cornwall were
for many years so systematically and exactly reported, and the reports of
each were so critically scrutinised by the rival makers, that the data they
supply may be relied on without hesitation. It was well known that the best
of the engines continuously performed useful work with a consumption of
coal at the rate of 2·33 lbs. per delivered horse-power per hour, or, counting
coal at 16s. per ton (a fair price on the South Devon), at the cost of ·2d., or
one-fifth of a penny per horse-power per hour.
But it was not in its consumption of fuel alone that stationary power was
the more economical; the expenditure in wages, oil, and tallow on one of
the pumping-engines above referred to, when doing 200 horse-power of
useful work, did not exceed 20s. for the twenty-four hours, or one-twentieth
of a penny per horse-power per hour, while the cost of repairs was merely
nominal.
Thus if fuel, wages, oil, and tallow be brought into one item, it is seen
that the cost of one horse-power in stationary engines such as the then
existing Cornish engines was only ·25d. per hour, or less than one-fourth of
its cost when developed by a locomotive, which has been shown to have
been 1·098d. per hour.

PLATE III

THE ROYAL ALBERT BRIDGE.
H. Adlard. Sc.

CHAPTER VII.

RAILWAY BRIDGES AND VIADUCTS.

1. BRICKWORK AND MASONRY BRIDGES—HANWELL VIADUCT—
MAIDENHEAD BRIDGE—FLYING BRIDGES—LETTER FROM MR.
BRUNEL ON BRIDGE CONSTRUCTION (DECEMBER 30, 1854)—2.
TIMBER BRIDGES—SONNING BRIDGE—BATH BRIDGE—
STONEHOUSE VIADUCT—BOURNE VIADUCT—ST. MARY’S VIADUCT
—VIADUCTS ON THE SOUTH DEVON RAILWAY—IVY-BRIDGE—
VIADUCTS ON THE SOUTH WALES RAILWAY—NEWPORT—LANDORE
—VIADUCTS ON THE CORNWALL RAILWAY—ST. PINNOCK—
VIADUCTS ON THE WEST CORNWALL AND TAVISTOCK RAILWAYS—
PRESERVATION OF TIMBER—3. CAST-IRON BRIDGES—LETTER ON
USE OF CAST IRON (APRIL 18, 1849)—HANWELL BRIDGE—
EXPERIMENTS ON CAST-IRON GIRDERS—EXTRACT FROM LETTER
TO SECRETARY OF COMMISSION ON APPLICATION OF IRON TO
RAILWAY STRUCTURES (MARCH 13, 1848)—4. WROUGHT-IRON
BRIDGES—GIRDER BRIDGES—EXPERIMENTS ON WROUGHT-IRON
GIRDER—OPENING BRIDGES—TRUSSED BRIDGES—NEWPORT
VIADUCT—WINDSOR BRIDGE—CHEPSTOW BRIDGE—METHOD OF
SINKING THE CYLINDERS—DESCRIPTION OF THE MAIN TRUSS—THE
FLOATING OPERATIONS—THE ROYAL ALBERT BRIDGE AT SALTASH
—THE CENTRE PIER—DESCRIPTION OF THE SUPERSTRUCTURE—
THE FLOATING AND RAISING OF THE TRUSSES—OPENING OF THE
BRIDGE BY H. R. H. THE PRINCE CONSORT—NOTE: EXPERIMENTS ON
MATTERS CONNECTED WITH BRIDGE CONSTRUCTION.

IN Chapter IV. a general history has been given of the railways of which Mr.
Brunel was the engineer; but the bridges and viaducts designed by him are
so numerous and important that it has been thought advisable to devote a
separate chapter to their consideration.
The bridges selected for mention have been grouped according to the
nature of the material used in their superstructure. This arrangement is the
most convenient one for giving a concise description of the most
remarkable of Mr. Brunel’s bridges, and for stating the circumstances which
guided him in the determination of the particular form of construction used
in each case.
The works are therefore divided into four groups, namely, brickwork and
masonry, timber, cast iron, and wrought iron.[77]
Brickwork and Masonry Bridges.[78]
The viaduct which carries the Great Western Railway over the valley of
the river Brent near Hanwell is the first of Mr. Brunel’s important railway
works.[79] It is a handsome brickwork structure, 65 feet high, with eight
semi-elliptical arches, each 70 feet span and 17 feet 6 inches rise. The
spandrils of the arches are lightened by longitudinal spandril-walls; the

piers are also hollow, and the structure is throughout made as light as
possible. It is on this account interesting, as showing the care taken by Mr.
Brunel from the commencement of his practice to distribute the material in
the simplest and most effective manner.[80]
The great bridge over the Thames at Maidenhead contains two of the
flattest, and probably the largest arches that have yet been constructed in
brickwork. The river, which is about 290 feet wide, flows between low
banks; in the middle of the stream there is a small shoal, of which Mr.
Brunel took advantage in building the centre pier.
It was originally intended that the foundation of the bridge should be on
the chalk, which was at a short distance below the surface; but it was found
to be very soft, and Mr. Brunel therefore decided to place the foundations of
the bridge on a hard gravel conglomerate overlying the chalk. The main
arches are semi-elliptical, each of 128 feet span and 24 feet 3 inches rise.
They are flanked at each end by four semicircular arches, one of 21 feet
span, and three of 28 feet span, intended to give additional water-way
during floods. The radius of curvature at the crown of the large arches is
165 feet, and the horizontal thrust on the brickwork at that point is about 10
tons per square foot.
In the interior of the structure immediately landward of the large arches,
Mr. Brunel constructed flat arches loaded with concrete. The centerings of
these were struck, and an active thrust opposed to the main arches before
their centerings were eased.[81] The line of pressure of each main arch was
diverted downwards by the thrust of the flat arch adjoining it without the
necessity of employing a great mass of brickwork in the abutment.
The woodcut (fig. 1) shows the form of the main arches and the flat arch
referred to.[82]

The Maidenhead bridge is remarkable not only for the boldness and
ingenuity of its design, but also for the gracefulness of its appearance. If
Mr. Brunel had erected this bridge at a later period, he would probably have
employed timber or iron; but it cannot be a matter of regret that this part of
the Thames, although subjected to the dreaded invasion of a railway, has
been crossed by a structure which enhances the beauty of the scenery.

There are two other large brick bridges over the Thames, one at
Gathampton and another at Moulsford, that at Moulsford crossing the river
obliquely at an angle of 45°. In each of these bridges there are four arches,
of 62 feet span on the square.
Other good examples of brick bridges are the turnpike road bridge, 60
feet high, with three arches, across the deep cutting at Sonning Hill, and the
bridge, with one opening of 60 feet and four side arches of 18 feet span,
over the river Kennet at Reading.
The bridge over the Avon at Bathford, of 87 feet span, and the bridge
crossing the same river at Bath, with an arch of 88 feet span, are handsome
Bath-stone structures with semi-elliptical arches. Near Bristol there is an
ornamental bridge of masonry with three Gothic arches, the centre arch
having a span of 100 feet.[83] Another bridge of Gothic design, with two
arches of 56 feet span, carries the railway over the Floating Harbour.[84]

The bridges which have hitherto been noticed are all on the Great
Western Railway. On the Bristol and Exeter Railway there is a large stone
bridge over the New Cut at Bristol, built in 1840, which has a single
segmental arch of 120 feet span, and 20 feet rise. Owing to some imperfect
workmanship in the interior masonry of the arch, and possibly to some
unequal yielding of the abutments, the crown sunk much more than had
been expected.
On his later railways Mr. Brunel did not build large arches of brickwork
or masonry, though he constructed several lofty and extensive viaducts of
these materials with spans varying from 40 to 60 feet.
Mr. Brunel seldom employed artificially piled foundations to support
masonry. When the ground was soft, he preferred to rely on a large extent of
bearing surface, and ensured uniformity of settlement by an accurate

distribution of the load. Several of his large viaducts and bridges, standing
on ground of a soft and spongy nature, were constructed on this principle.
A class of bridge of striking outline was used in the cuttings on the
Bristol and Exeter Railway, and on the other railways subsequently made.
Bridges of this class were called flying bridges. Instead of arches resting on
piers and abutments, the bridge has a single arch, reaching from one side of
the cutting to the other, and springing from the slopes, which it helps in
some measure to support. A flying bridge of large dimensions near Weston-
super-Mare carries a road across the cutting at a height of 60 feet above the
line of rails, with a clear span of 110 feet.
The quantity of masonry in these bridges is much less than in those of
the ordinary construction; and lofty and expensive centering is not required,
as the bridge can be built before the cutting is excavated to its full
dimensions.
This class of bridge, by the avoidance of abutments and counterforts,
simplifies the construction of skew arches, while on sharp curves it presents
but little obstruction to the view along the line.
A curious use of arches of this construction, as applied by Mr. Brunel,
may be seen on the South Wales Railway near Llansamlet, between Neath
and Swansea. A deep cutting through the coal measures showed a tendency
to slip, and a large amount of excavation would have been required to
flatten the slope, as a hill rose immediately above the side of the cutting.
Four of these flying arches were thrown across the cutting at short intervals,
and weighted with heavy copper slag, so that the sides of the cutting are
kept apart by the thrust of the loaded arches.
Among the skew bridges on Mr. Brunel’s railways, there are a few of
extreme obliquity. Of these may be mentioned two large road bridges near
Berkeley, over the Bristol and Gloucester Railway, one being 48° and the
other 53° off the square. Both the bridges are of brickwork, and in the arch
of the first one, which was set in Roman cement, hoop iron was introduced
in the manner successfully employed by Sir Isambard Brunel. On the South
Devon Railway, near Plympton, there is a skew bridge 63° off the square.
On the Great Western Railway, in the neighbourhood of Bath and
Bristol, there are skew bridges of ashlar masonry built on the mechanically
correct principle of spiral tapering courses, the bed-joints in every part of
the arch being made at right angles to the lines of pressure. By this method

the arch does not depend for its stability on the friction and cohesion of the
materials, as it does to a great extent in very skew bridges, built in the usual
way with spiral parallel courses, especially when the arches are semi-
circular or semi-elliptical.

Mr. Brunel’s bridges of masonry and brickwork were well known for the
comparatively small quantity of material used in them; and, though it was
requisite that the materials and workmanship should be of superior quality,
their cost was comparatively small.
The specifications he prepared for all his works, and on which the
contracts were based, were noted for the completeness with which they
were drawn up, and for their not requiring a standard of perfection higher
than that which was actually to be carried out. The confidence with which
Mr. Brunel was regarded enabled him to insist with effect on the work being
executed according to his interpretation of the contract.
In connection with the design of engineering works, and especially of
brickwork and masonry bridges, the following letter from Mr. Brunel to one
of his assistants, who was abroad, will be found interesting:—
December 30, 1854.
Let me give you one general piece of advice—that while in all works you endeavour to employ
the materials used in the most economical manner, and to avoid waste, yet always put rather an
excess of material in quantity. You cannot take too much pains in making everything in equilibrio;
that is to say, that all forces should pass exactly through the points of greater resistance, or through
the centres of any surfaces of resistance. Thus, in anything resembling a column or strut, whether of
iron, wood, or masonry, take care that the surface of the base should be proportioned that the strain
should pass through the centre of it. Consider all structures, and all bodies, and all materials of
foundations to be made of very elastic india-rubber, and proportion them so that they will stand and
keep their shape: you will by those means diminish greatly the required thickness: then add 50 per
cent. So in trussed framework of wood or iron, experience shows that you cannot refine too much
upon the perfection of the designing of every little detail by which all strains are carried exactly
through the centres of the rods or struts and the centres of the bearing surfaces. And remember,
always in retaining walls to give plenty of batter; never build an upright wing-wall, or retaining wall.
To a man who has an instinctively mechanical mind—and no other can be an engineer—the advice I
have given you above is all I need say; but this advice is the result of a good deal of experience,
purchased by failures of my own, and by looking at those of others, and is, I assure you, valuable
advice, to be followed literally and strictly, and not to be considered as a mere theoretical refinement,
to be neglected in practice. Practically too much attention cannot be paid to these precautions. I have
found that there is not a single substance we have to deal with, from cast-iron to clay, which should
not practically be treated strictly as a yielding elastic substance, and that the amount of the
compression or tension, as the case may be, is by no means to be neglected in practice any more than
in theory. Bear in mind also that which is too often neglected and involves serious consequences, that

masonry or brickwork has not half the strength which is generally calculated upon until the mortar is
hard, and that you cannot keep centres or shores up too long.

Timber Bridges and Viaducts.
Mr. Brunel’s timber bridges and viaducts are remarkable on account of
the extensive scale on which he employed that material, and the simple and
efficient type of construction which he adopted in the largest structure as
well as in the smallest.
In 1841 Mr. Brunel constructed a timber bridge of five spans to carry a
public road over the Sonning cutting of the Great Western Railway, a short
distance east of Reading. The total width of the space across which the road
had to be carried was 240 feet. The superstructure rests on four tall
frameworks or trestles of timber forming the piers. Two of these piers are
on either side of the railway, and the others are about halfway up each
slope.
The road rests on a platform of timber planking, carried on three
longitudinal beams, which are supported at nearly equal distances by timber
struts radiating from points on the piers about 12 feet below the level of the
carriage road. The system of arrangement of these struts will be best
understood by a reference to the woodcut given below (fig. 5, p. 187) of one
of the Cornwall viaducts, of which the Sonning bridge may be regarded as
in some measure the prototype.[85]

The skew timber bridge on the Great Western Railway near the Bath
Station, carrying the line over the river Avon, was constructed about the
same time as the Sonning bridge. It has two spans of 36 feet each on the
square, but the obliquity is so great that the span on the skew is 89 feet.
Each opening has six laminated arched ribs parallel to the line of the
railway. These support the platform of the bridge, and are built up in five
layers of curved Memel timber, six inches thick, bolted together. The thrust
is counteracted by iron ties connecting the ends of the ribs. The inner
spandrils are filled in by cross-ties and braces, and those of the outer ribs by
ornamental cast ironwork.

The two bridges already described are almost the only timber bridges of
importance on the main line of the Great Western Railway from London to
Bristol. Shortly after the completion of this railway Mr. Brunel began to

make an extensive use of timber in his designs, and in so doing took full
advantage of the largeness of the material, in order to avoid intricacy of
construction.
A well-known arrangement for forming beams of greater strength than
could be obtained by single pieces of timber was adopted by Mr. Brunel
after a careful investigation of its merits. This arrangement consists in
joining together two beams of timber placed one above the other, by means
of bolts and joggles, so as to form a beam nearly equivalent in strength to a
single piece of timber of the same depth as the two pieces united.[86] By this
plan, the length which could be spanned by simple beams, without the
introduction of trussed framework, was nearly doubled.
The distance between the piers of railway bridges is generally too great
to allow of the superstructure being constructed of simple beams, and in
such cases Mr. Brunel adopted forms of framing similar in the arrangement
of their parts to the common designs of king and queen trusses employed in
roofs.

One of Mr. Brunel’s early timber viaducts was that erected in 1842 at
Stonehouse, on the Bristol and Gloucester Railway. It consisted of a series
of five openings of queen trusses 50 feet span, resting on piers formed of
timber trestles.
In the Bourne viaduct, across the Stroudwater
Canal, on the Cheltenham and Great Western Union
Railway, there was a span of 66 feet, with three
timber trusses, for the two lines of way. Each of these
trusses may be described as a king truss with an
internal queen truss. The inclined timbers or
principals rested in iron shoes upon the piers, and
were connected together by bolts and joggles.
The upper horizontal or collar beam of the queen truss carried the
roadway planking, which was continued upon beams supported by the
principals. The timbers carrying the roadway received support from struts
radiating from the feet of the queen posts, which were connected with the
apex of the king truss by iron ties. The horizontal tie bars were of wrought
iron. The arrangement of the truss is shown in the woodcut (fig. 2).

The side openings consisted of four spans of 30 feet, with trusses of the
Stonehouse viaduct type, of one span of 25 feet and ten spans of 20 feet,
with double beams.
The St. Mary’s viaduct, across the canal in the Stroud Valley, was
constructed with one span of 74 feet, with trusses similar to those at the
Bourne viaduct.[87]
In the year 1846 Mr. Brunel made an elaborate series of experiments on
the strength of large timber. Some account of these is given in the note to
this chapter.
Fortified by the information thus obtained, he was able to proceed with
confidence to an extensive use of timber in the viaducts of the South
Devon, the Cornwall, and other railways.
Between Totness and Plympton, the South Devon Railway, running
along the skirts of Dartmoor, crosses four deep valleys, by lofty viaducts,
all of the same design.
Three of them can be seen at one time, and they form striking and
elegant features in the landscape.
The viaduct at Ivybridge is the highest of these. It is on a curve, and has
eleven openings of 61 feet each; the extreme height is 104 feet.
The piers are of masonry, each consisting of two slender and slightly
tapered shafts about 7 feet square, rising to the level of the rails. The
superstructure was originally designed for a railway on the Atmospheric
System, and was therefore only intended to bear the load of a train of
carriages. The framework was placed below the level of the rails, and, as
will be seen in the woodcut (fig. 3), it consists of a polygonal frame, with a
few subsidiary struts, the feet of the main timbers being tied together by
wrought-iron rods. There are two of these frames, one at each side of the
bridge, to support the planking of the roadway. Before the construction of
the viaducts was proceeded with, a complete span of the superstructure,

consisting of a pair of the frames with
the planking, was erected at Bristol,
and tested to ascertain the efficiency of
every part.
When it became necessary to
strengthen the superstructure to enable
it to carry the weight of locomotives, a
strongly trussed parapet was added
above the trusses, as shown in the
woodcut. After the lapse of twenty
years, the timber having begun to
decay, wrought-iron girders have been
inserted, which rest on the stone piers;
the framing, however, has not been
removed.

Shortly after the completion of the viaducts on the South Devon
Railway, those on the South Wales Railway were constructed. The most
important on this line are those at Landore and Newport.
The viaduct at Landore, near Swansea, is 1,760 feet long, as the railway
here crosses a wide valley. It has 37 openings, and there are a variety of
spans, one of 100 feet, two of 73 feet, two of 64 feet, two of 50 feet, and the
rest of about 40 feet each. Most of these consist of a superstructure of queen
trusses. The piers are of different materials, some being almost entirely of
masonry, some partly of masonry and partly of timber, and others entirely
of timber, according to the nature of the foundation.[88] The chief feature is
the centre span, with an opening of 100 feet, the superstructure of which is
a very fine piece of timber-work.[89] It has four trusses, one on either side of
the two lines of rails, of the form shown in the woodcut (fig. 4). The truss
consists of a four-sided frame placed within a five-sided frame, the angles
of each polygon being connected by bolts and struts with the middle of the
sides of the other polygon.

The planking of the roadway rests on double beams, supported at several
points in the manner shown in the woodcut, each point having suspension-
rods to connect it with the nearest angles of the frames. The arrangement of
the double polygonal frame and of the tie-rods enables the transverse
strength of the timbers to exercise considerable resistance to any distortion
of the shape of the truss by a rolling load. To prevent any tendency of the
top of the frame to yield sideways under the compressive strain, the tops of
the trusses are connected by transverse struts or braces, the two outside
trusses being steadied by raking ties attached to outriggers projecting from
below the flooring of the bridge. The thrust of the polygonal frames is
resisted by wrought-iron tie-bars at the level of the roadway beams. All the
tie-rods in this bridge are double, with one bar on each side of the timbers,
to avoid the necessity of making large bolt-holes.[90]
The viaduct at Newport consists of eleven spans with queen trusses,
resting on piles. The main span, over the river Usk, is 100 feet, and was
constructed with timber trusses very similar to those at Landore. Shortly
before it was finished, the viaduct was burnt down. In rebuilding it,
wrought-iron trusses were employed for the main span.

The works of the Cornwall Railway were commenced in the year 1852.
The district through which the line passes is very deficient in the materials
requisite for the construction of a railway. The granite of the country is for

the most part only applicable for ashlar; and the slate, which is flat-bedded
and so far fit for rubble masonry, is frequently inferior in quality.
In consequence of the number of valleys that the railway had to cross,
the aggregate length of the viaducts, thirty-four in number, exclusive of the
Saltash bridge, is upwards of four miles on a line of sixty miles. By the use
of timber, a great saving was effected in the first cost of the works; and
though it is a material which in time requires renewal, its use on the
Cornwall Railway enabled the line to be made with the capital at the
command of the Company; while, allowing for the cost of subsequent
repairs, the total expenditure did not differ much from what it would have
been had the superstructure of the viaducts been of more durable materials.
The comparatively small cost of these structures enables them to be, in
certain places, economically substituted for embankments, as was done on
the Cornwall Railway.
The viaducts are to be found over the whole length of the line, but they
are most frequent between the Liskeard and Bodmin Road stations, where
the railway crosses numerous branches of the Glynn valley.
Most of these viaducts are of one type of construction.
The piers are formed of plain walls, built up to thirty-five feet below the
level of the rails, those of the more lofty viaducts being strengthened by
buttresses. In the woodcut (fig. 5) is shown a portion of the St. Pinnock
viaduct, from which the form of these piers will be understood.
This viaduct is the loftiest on the Cornwall Railway, the rails being at a
height of 153 feet above the ground. A description of the superstructure will
serve to explain the design of the principal viaducts on the line.
The roadway planking rests on three beams, which run longitudinally
throughout the whole length of the viaduct. Each of these beams consists of
two pieces of timber, one above the other, fastened together by bolts and
joggles. The piers are 66 feet apart, centre to centre, and the longitudinal
beams are supported, at four nearly equidistant points in this space, by
straight single timbers radiating from the tops of the piers. The feet of the
timbers, which rest on the masonry in cast-iron shoes, are connected
together by wrought-iron tie-bars; and the framework is made rigid by iron
diagonals.

It will be observed in the transverse section (fig. 5) that the whole weight
of the superstructure is concentrated immediately over those points in the
piers where the three buttresses meet. The diagonal braces which are
attached to each set of the main timbers give transverse stability to the
superstructure.[91]
It was desirable, both in first construction and in subsequent repairs, to
have a uniform dimension for the spans, and the subdivision of 66 feet was
determined on as being suitable for the economic construction of the greater
part of the work. The subdivision of this length was such as to allow of
single whole timbers being sufficient for the direct supports of the
longitudinal beams; and as these beams were supported at intervals of 15 to
20 feet, no intermediate trussing was required. As the inclined timbers met
the tops of the piers at a moderate inclination, the outward thrust caused by
unequal loading of the spans of the viaduct was inconsiderable, and was
easily counteracted by light iron ties.
The stone for the piers was for the most part procured in the
neighbourhood, the design of the masonry being such as to enable stone of
the country to be used; and, as the timber superstructure was built in pieces

of moderate size,[92] and easily obtained, the expenditure was probably not
far from the minimum under the existing conditions.[93]
On the South Devon and Tavistock Railway, the viaducts are six in
number, and from 62 to 132 feet in height. In these the piers were made of a
somewhat simpler form than those just described. At the lofty viaducts, the
buttresses were made with a uniform batter throughout their height. The
Walkham viaduct, near Tavistock, 132 feet high, with fifteen openings of 66
feet span each, may be considered to exhibit the most matured design of Mr.
Brunel’s timber viaducts.
On the West Cornwall Railway a type of viaduct similar to that described
above was adopted; but as the general height was not so great, the spans
were 50 feet each, and the longitudinal beams were supported at three
points in each span, instead of at four as on the Cornwall Railway. In
consequence of the nature of the foundations, the piers of the nine viaducts
on this line were for the most part formed of upright timbers well braced
together, standing upon masonry footings. The viaduct at Angarrack, 98 feet
high, with 16 spans, which was constructed in 1851, was remarkable for its
light appearance, owing to the small number of timbers in the
superstructure and piers.
Mr. Brunel paid great attention to the preservation of the material of the
timber bridges and viaducts. As early as 1835 he had been in
communication with Mr. Faraday as to the best method of testing the extent
to which the Kyanising solution penetrated into wood. Mr. Brunel made a
careful trial of all the different methods of preserving timber, and employed
the more successful of them on a very considerable scale. He was so
impressed with the importance of the preserving processes being properly
applied, that he on several occasions preferred to keep the operation of
preserving the timber in the hands of the Company, in order that it might be
done thoroughly, and under his own supervision. He also minutely attended
to the details by which timber structures may be protected from decaying
influences.
Cast-Iron Bridges.
Mr. Brunel did not make an extensive use of cast iron for the
superstructure of bridges. His views as to the employment of this material
in girders are clearly expressed in the following extract from a letter to one
of the Directors of the Great Western Railway:—

April 18, 1849.
Cast-iron girder bridges are always giving trouble—from such cases as the Chester Bridge, and
our Great Western road bridge at Hanwell, which, since 1838, has always been under repair, and has
cost its first cost three times over, down to petty little ones, which, either in frosty weather or from
other causes, are frequently failing. I never use cast iron if I can help it; but, in some cases it is
necessary, and to meet these I have had girders cast of a particular mixture of iron carefully attended
to, and I have taught them at the Bridgewater foundry to cast them with the flange downwards
instead of sideways. By these means, and having somebody always there, I ensure better castings,
and have much lighter girders than I should otherwise be obliged to have. The number I have is but
few, because, as I before said, I dislike them, and I pay a price somewhat above ordinary castings,
believing it to be economy to do so.
I won’t trust a bridge of castings run in the ordinary way, and at foundries where I have not a
person always watching; and, even if I did, the weight requisite in a beam of ordinary metal and
mode of running would more than make up for the reduced price.

The bridge at Hanwell referred to in this letter was one on the main line
of the Great Western Railway, over the Uxbridge road. In 1847 the planking
caught fire, and the cast-iron girders were destroyed by the heat.
The researches of Mr. Eaton Hodgkinson had drawn attention to the
importance of a proper proportionment of the top and bottom flanges of
cast-iron girders, and Mr. Brunel now made some experiments on this point.
As part of this investigation, eight girders, 30 feet long and 16 inches deep,
were tested by weights until they gave way. The comparative areas of the
top and bottom flanges were varied until a correct proportion between the
two was arrived at. The general result of these large-scale experiments
showed a lower breaking-weight than that deduced from Mr. Hodgkinson’s
formula.
When Mr. Brunel afterwards had occasion to use cast-iron girders, which
was chiefly for road bridges over railways, they were made of the form
which his experiments had shown to be the best;[94] but he repaired the
Hanwell Bridge with wrought iron.
At about the same time the necessity for spanning wide openings had led
to larger girders being required than could be manufactured in single
castings, and Mr. Brunel had a large cast-iron girder made, 46 feet long and
4 feet deep, of five pieces bolted and keyed together. It was tested until it
gave way with a load of 92 tons on the middle. The result showed that the
several parts had been well connected, and that the strength of the beam
was not much less than the calculated strength of a beam of the same size in
a single piece. Mr. Brunel did not, however, use girders of this construction,
as the rapid introduction of wrought iron rendered it unnecessary.

Cast iron was introduced, though not for girders, in many of the brick
and stone bridges on the Great Western Railway. It was used in the form of
troughs sunk into the crown of the arch in bridges where the headway was
very limited. The rails were laid along the bottom of the trough within a few
inches of the soffit or underside of the arch.
Although, after the careful experiments and investigations he had made,
and the experience he had obtained, Mr. Brunel did not make use of cast
iron for large girders, he looked forward to the possibility of such
improvements being introduced into the manufacture as would enable
sound castings of considerable size to be made of homogeneous material.
He expressed this opinion in a letter to the Secretary of the Commission
on the Application of Iron to Railway Structures. This Commission (which
Mr. Brunel called ‘The Commission for stopping further improvements in
bridge building’) was appointed ‘for the purpose of inquiring into the
conditions to be observed by engineers in the application of iron in
structures exposed to violent concussions and vibration.’ Mr. Brunel, in
common with most engineers, thought it would be very inexpedient that any
règles de l’art should be laid down, and took up the cudgels boldly on
behalf of the liberty of the profession:—
March 13, 1848.
At present cast iron is looked upon, to a certain extent, as a friable, treacherous, and uncertain
material; castings of a limited size only can be safely depended upon; wrought iron is considered
comparatively trustworthy, and by riveting, or welding, there is no limit to the size of the parts to be
used. Yet, who will venture to say, if the direction of improvement is left free, that means may not be
found of ensuring sound castings of almost any form, and of twenty or thirty tons weight, and of a
perfectly homogeneous mixture of the best metal? Who will say that beams of great size of such a
material, either in single pieces or built, may not prove stronger, safer, less exposed to change of
texture or to injury from vibration, than wrought-iron, which in large masses cannot be so
homogeneous as a fused mass may be made and which when welded is liable to sudden fracture at
the welds?[95]

Wrought-Iron Bridges.
Notwithstanding the cost of wrought iron, but a short time elapsed
between its introduction into bridge building and its use in structures of
great magnitude. Mr. Brunel had been long familiar with the application of
riveted wrought-iron work, and he was the first to encourage its use on a
large scale in shipbuilding by recommending its adoption in the ‘Great
Britain’ steam-ship in 1838.
Girder Bridges.

The strains on girders made of homogeneous material have been
carefully and ably calculated by mathematicians; and the investigations thus
made have directed inquiry into the right channels for determining the
nature of the stresses on the several parts of the built-up structures now so
much in use. Principles have by degrees been laid down, and lines of
thought have been suggested and followed out which were unknown at the
time when wrought-iron girders were first introduced in the construction of
railway bridges.[96]

Shortly after Mr. Brunel began to use wrought iron for
bridge girders, he made an experiment in order to determine
the weak points of a large wrought-iron plate-girder. Mr.
Edwin Clark, in his work on the ‘Britannia and Conway
Tubular Bridges,’ vol. i. p. 437, gives a description of what
he justly terms ‘this magnificent experiment.’ The girder was
of the section shown in the woodcut (fig. 6), 70 feet in
length, and of ¼-inch plate throughout. It was weighted
gradually, and gave way with a load of 165 tons on the
centre, by the tearing apart of the vertical web plate near the
ends of the girder. When this portion had been strengthened,
and the girder again loaded, it gave way with a load of 188
tons by the simultaneous failure of the top and bottom
flanges, that is to say, of the plates forming the triangles
shown in the woodcut.[97]
The superior tensile strength of wrought iron to that of cast iron, and the
facility with which pieces could be joined together by riveting, enabled
girders of great size to be made. The thin wrought-iron plates were arranged
so as to form the top and bottom flanges of the girders as well as the upright
web connecting them. The metal in the top of a girder being in
compression, it was important so to dispose it that it should resist the
tendency to yield sideways under the strain. This requirement was met in
the experimental girder by the triangular section of the top flange; and the
convenience of this form for joining together a number of plates, without
difficulty or the use of long rivets, led Mr. Brunel to use the triangular
section also for the bottom flange.

Subsequent improvements in the facilities for bending
wrought-iron plates enabled him to use a form of cross
section of wrought-iron girder, the top flange of which was a
nearly circular tube, the best shape of strut to resist
longitudinal compression. It is shown in the woodcut (fig. 7),
and was used in many of his bridges.
This form was afterwards modified to that shown in fig.
8. The semicircular top plate is stiffened by occasional cross
diaphragms, and while it was a good form to resist
compression, it was more easily painted than the closed-in
top flanges shown in figs. 6 and 7.
The forms of wrought-iron girder already referred to are those known as
plate girders, with continuous webs made of plates riveted together, and
therefore analogous to the beams of cast iron which they almost entirely
superseded. On Mr. Brunel’s railways there are a great number of bridges of
these forms of girder, where the spans do not exceed 100 feet. For larger
spans he used wrought iron, in large and deep trussed frames, by which
means a great degree of economy was attained in the employment of the
material.
The care which he had taken to satisfy himself of the
action of the strains in plate girders was of service in all the
greater structures he designed, as in all of them he employed
wrought-iron girders to carry the roadway, of a type
somewhat similar to those already described, the girders
being supported at frequent intervals by the main framework
or truss.
Opening Bridges.
The first large opening bridge which Mr. Brunel
constructed was a roadway swing bridge, 12 feet wide,
across the new lock at the Bristol Docks. The length of the
overhanging end is 88 feet, and the other, or tail end, which
is 34 feet long, rests upon two wheels, which travel on a
circular rail. The weight of the overhanging end is rather more than
counterbalanced by large blocks of cast iron, forming part of the pavement
of the tail end. Almost the whole weight is borne on a centre pivot, assisted
by four wheels in fixed bearings, upon which runs an inverted circular rail

attached to the underside of the bridge. On the pivot, which rests on a large
cast-iron bed-plate, are two discs, one of steel and the other of brass, which
can readily be lubricated, or taken out and renewed.
On the sides of the bridge are longitudinal wrought-iron
plate-girders. The top flange is pear-shaped, and the bottom
flange triangular, having three curved plates. The flanges are
connected together by a vertical plate web of wrought iron.
The section is shown on the woodcut (fig. 9). It admits of
very simple riveting, without the use of angle irons. The
form of the bottom flange is suited to the compressive strain
it has to bear when the bridge is being moved. The top flange
has also wrought-iron tie-bars within the tube. When the
bridge is across the lock and open for traffic, the overhanging
end rests on cams, which are tightened up so as to lift and support the ends
of the girders. As the bridge rests almost entirely on a pivot of small
diameter, it turns with great ease.
Near Gloucester there are two skew swing bridges somewhat similar to
each other in arrangement. Almost all the weight while turning is supported
on the piston of a hydraulic press, and the bridge therefore turns round on
the water in the cylinder. The first bridge is on the main line of railway
leading to South Wales, across a branch of the River Severn, and is for two
lines of way. It has three girders, 125 feet long, of the form shown in fig. 7
(p. 194). The water pivot is in the middle of the length of the bridge, which
spans two openings of 50 feet on the square. Before being turned the bridge
was intended to be lifted slightly off its bearings by the hydraulic press, and
steadied by four wheels, on which a portion of the weight was to be made to
rest by long springs within the girders, the range of which was to be limited
in one direction by a fixed stop. The central pier consists of five cylinders
of cast iron, each 6 feet in diameter, filled with concrete, surmounted by a
cast-iron ring or roller path. The railway company was obliged to make this
an opening bridge in order to provide for the free navigation of the river
should the old stone bridge lower down be altered. This has not been done,
and the railway swing bridge, constructed in 1851, has not yet been opened.
The other swing bridge at Gloucester is on the Dock branch, for one line
of way, with an opening of 50 feet on the square, the overhanging length of
the girders being 70 feet. While raised from its bearing and turning on its

water pivot it is steadied by two tail wheels, like the bridge at the Bristol
Docks.
On the Bullo Pill branch of the South Wales Railway there is a small
wrought-iron drawbridge, for one line of way, of 30 feet span. It is a lifting
bridge on the bascule principle, like many bridges over canals in this
country and in Holland. The opening part turns on a horizontal axle, and is
lifted by rods attached to the ends of two large beams or levers, turning
vertically, which are supported above the railway on a timber framework.
At the other ends of these beams is a counterbalance weight. The bridge is
opened or shut by pulling down either end of the beams with a small chain.
The other bridges are on the main line of the South Wales Railway, and
are four in number, each for two lines of way.
One at Loughor is a wrought-iron swing bridge, of 30 feet opening, of
the ordinary construction, with girders 90 feet in length, resting upon 36
rollers, which are secured in a ring concentric with the pivot. The opening
and closing is effected by means of a crab, fixed clear of the bridge, near
the centre. A chain passes from the overhanging end of the bridge to this
crab, and taking one or two turns round the barrel, to ensure a sufficient
amount of friction, is led to the tail end. The bridge can thus be opened or
shut by turning the crab handle in opposite directions. The overhanging end,
when across the river, is raised upwards to a small extent by weighted
levers, and wedges are then drawn in under it to give it a solid bearing.
At Kidwelly and at Haverfordwest there are wrought-iron lifting bridges,
the former of 20 feet, and the latter of 30 feet span. Each of these turns on a
horizontal axle like the Bullo Pill bridge; but, instead of being lifted by
levers overhead, it has a narrow, heavily-weighted tail end, beneath the
planking of the viaduct, which is pulled down with a chain worked by a
crab. The portion which carries each line of way is made to open
independently. In this form of bridge no wedges or adjusting arrangements
are required for the bearings of the overhanging end.
Over the river at Caermarthen is a skew bridge of three girders, each 116
feet long, for a double line of way. It occupies two spans and rolls back, so
as to leave a 50-feet opening for the navigation. The swing bridge at Bristol,
already described, was at first intended to be a rolling bridge, and to be
furnished with wheels to run back on fixed rails, but the difficulty of
forming a good foundation for the wheel path led to the design being

altered. At Caermarthen the same difficulty was overcome by putting
wheels turning in fixed bearings on the pier and abutment of the bridge. The
undersides of the girders carry inverted rails, and run back on the wheels.
The bridge, when shut, is on an incline of 1 in 50. When about to be opened
it is made to assume a horizontal position by turning a supporting cam to
lower the overhanging end, and the tail end then rises sufficiently to pass
clear above the part of the railway over which it runs back.
By this arrangement the bridge, while in motion, moves along a level
path. It is opened and closed by hydraulic machinery.
All these opening bridges have worked satisfactorily since they were
constructed.
Trussed Bridges.
When the timber viaduct over the river Usk, at Newport, was burnt
down,[98] Mr. Brunel decided to form the new superstructure of the centre
opening with three iron trusses, for the two lines of way.
These are bow and string girders, of 100 feet span, and were made of
considerable height, not only to reduce the strain on each of the members of
the framework, but also in order that the rib or upper portion of each truss
might be braced diagonally to the corresponding portion of the other
trusses, and headway left for the locomotive chimneys to pass underneath.
This bracing counteracts any tendency of the ribs to bend sideways under
the compressive strain. The form of the trusses is shown in fig. 1, Pl. IV. (p.
206). Each truss is a wrought-iron polygonal arch of triangular section,
from which is suspended a horizontal girder supporting the roadway. This
girder also forms the tie which connects the feet of the arch and counteracts
its thrust. The diagonal braces shown on the elevation of the bridge prevent
the arch from being distorted by the unequal loading caused by a passing
train. The middle truss is twice the strength of each of those at the outside,
being made so by increasing the thickness of the plates. One of the outside
trusses was tested with a distributed load of 1½ tons per foot-run of its
length.
At about the same time that the Newport viaduct was reconstructed, Mr.
Brunel designed the bridge over the Thames on the Windsor branch of the
Great Western Railway. This is a very large example of the bow and string
girder, the span being 202 feet, and the height of the truss 23 feet. The
trusses are three in number, for two lines of way, the middle one being

twice the strength of the outside trusses. The elevation of
the Windsor bridge is shown in fig. 2, Pl. IV. (p. 206).
The bridge is oblique to the river, being 20° off the
square. To steady the arched ribs sideways a system of
diagonal bracing extends over the whole of the top of the
trusses, except at the ends, where headway has to be left
for the trains.
A section of the arched ribs and of the roadway girders
in the centre of one of the trusses is given in the woodcut
(fig. 10). The arched rib, to resist compression, is of
triangular section.[99]

The borings to ascertain the nature of the ground at the
foundations of the piers were made in 1846, but it was
not until 1848 that the works were commenced. Each
abutment consists of six cast-iron cylinders, 6 feet diameter, which were
sunk by excavating the gravel from their interior by hand dredging and by
placing weights on the top so as to force them down.
When each cylinder had been by this means sunk low enough to ensure a
good foundation, it was filled with concrete in the following manner. A
mixture formed of Thames ballast and Portland cement, in the proportions
of 8 to 1, was put into a canvas bag; this was lowered inside the cylinder to
the bottom, and, by pulling a rope, the mouth of the bag was opened, and
the concrete deposited under water in the bottom of the cylinder. Whenever
the work was interrupted, great care was taken before recommencing it to
clean off any deposit, in order that the new concrete might adhere well to
the old. When the cylinder had been filled to such a height that there was no
danger of its floating up when emptied, the water was pumped out. The
inside was then filled with concrete in the ordinary manner. On the top were
placed oak platforms, which support the trusses of the bridge.
One of the outside trusses was tested at Bristol in July 1849, by loading
it gradually with iron rails, beginning from one end, until the whole truss
was uniformly weighted with 270 tons, or 1½ tons per foot-run,
observations on the deflection of different points of the bottom girder being
made both during the loading and unloading. The results of this test were
perfectly satisfactory.

The superstructure of the bridge was erected on scaffolding, and the line
was opened on October 8, 1849.

It will be desirable here to notice one or two important features in this as
in almost all Mr. Brunel’s bridges.
The ordinary permanent way was laid over the bridges with ballast of
sufficient thickness to enable the road to be kept in repair in the same
manner as the other parts of the line. As there was no change in the nature
of the support given to the rails, no concussion was caused on a train
entering or leaving a bridge. The ballast took off from the structure the
vibration of the train; and, in the event of carriages or even engines getting
off the line, it helped in a great measure to prevent their ploughing through
the flooring. Where the flooring was of timber the ballast protected it from
fire. Also in long bridges there was no necessity for any contrivance of
sliding rails to allow for the effects on the structure of changes of
temperature. On the other hand, the ballast added to the weight on the
bridge. With the timber viaducts this was an advantage, since it kept the
various parts of the framework in close contact, and prevented sudden jars
being brought on them by the rapidly applied load of a passing train. Even
on the large bridges the cost of the extra material requisite to support the
weight of the ballast was more than compensated for by the advantages
above referred to.
Mr. Brunel employed timber flooring, as being the safest in the case of
carriages getting off the line, and also as being the cheapest. This flooring
in the iron bridges was generally laid diagonally on wrought-iron cross
girders, which were placed not at right angles to the line, but obliquely, in
order that the two wheels of the same axle of an engine or heavy waggon
might be on different cross girders at the same time. By this arrangement
the cross girders could be made of less strength, and a saving effected in
their cost and weight.
The bridge over the Wye at Chepstow, and the Royal Albert Bridge over
the Tamar at Saltash, are the largest and most important of Mr. Brunel’s
bridges.
They are remarkable not only for their dimensions, but also for the
economical character of the designs, the form of their superstructures, and
the methods by which the foundations of the piers were made.

At the part of the river Wye where it is crossed by the Chepstow Bridge,
a cliff of limestone rock rises on the left bank to a height of 120 feet above
the bed of the river, forming the precipitous edge of a broad table-land;
while on the right bank the ground slopes gently for a considerable distance,
rising only a little above high water, and is composed partly of clay and
partly of loose shingle interspersed with large boulder stones. As it was
necessary to leave a clear headway of 50 feet above high water for the
navigation, the line on one side of the river is on an embankment of great
height, and on the other side it penetrates the cliff about 20 feet below the
top. The whole space to be bridged over, 600 feet wide, was divided into a
river span of 300 feet, and three land spans of 100 feet each (see fig. 3, Pl.
V. p. 206.) At one end of the great span a secure abutment was offered by
the cliff of limestone rock; but at the other end, and under the piers of the
smaller spans, the ground throughout was soft, and full of water. There was,
however, rock at a depth of 30 feet below the bed of the river.
To reach this foundation with masonry, by means of a coffer dam, was
almost impracticable, as it was 84 feet below high water.
The plan of building a stone pier on a foundation of piles was
considered, and abandoned on account of the expense.
The method of sinking the cast-iron cylinders of the Windsor bridge has
been already described. The pneumatic process of sinking cylinders had
been introduced with great success at the Rochester bridge.
In this process the cylinder is closed at the top and air forced in by
pumps until the water is expelled at the bottom. Workmen in the interior
excavate the ground and remove any obstacles which prevent the cylinder
from sinking, weights being added to force it down. As the air within is at
high pressure, the workmen enter, and the materials are passed in and out,
through an intermediate chamber, called an ‘air lock,’ fitted with air-tight
doors. The pneumatic method was ultimately employed at Chepstow, to
assist in sinking the cylinders.
Before he decided on the plan for the foundations, Mr. Brunel had an
experimental cylinder made of cast iron, 3 feet in diameter, at the bottom of
which was an exterior screw flange 12 inches broad, and 7 inches pitch,
making one complete turn. This screw cylinder penetrated the ground like
an ordinary screw pile. In one instance it was rapidly sunk to a depth of 58
feet, through stiff clay and sand, in 142 revolutions;[100] yet, on another

trial, when boulders were encountered, there did not appear to be sufficient
penetrating power. In one of these trials, the screw, having got into a bed of
running sand, had no hold, and failed to descend. Mr. Brunel then had the
cylinder partly raised, and another screw added at some distance above the
lower one. It was then successfully screwed down.
Mr. Brunel, however, ultimately decided on forming the piers of cast-
iron cylinders forced down by loading and afterwards filled with concrete,
and the work was commenced in the spring of 1849.
With this form of construction all uncertainty of obtaining a secure
foundation was removed, as the pneumatic method was in reserve, in case
of excessive influx of water, to sink the cylinders to the rock, if it could not
be reached by simpler means; and additional cylinders could be added, so as
to obtain any amount of area of base that might be thought necessary.
The land piers for the 100 feet spans consist each of three cylinders,
which are 6 feet in diameter, joined together in lengths of 7 feet. The main
pier, which supports one end of the great truss, consists of a double row of
cylinders, six in all, the lower parts of which are 8 feet in diameter, joined
together in lengths of 6 feet. The bottom of each cylinder was made with a
cutting edge, so as to penetrate the ground easily.
Most of the cylinders were sunk by the process of excavating the ground
within them and weighting the top, the water being kept down by pumping.
As the ground consisted chiefly of wet sand and shingle, danger was
apprehended from its tendency to run in from the outside, while the
excavation was in progress. This would have diminished the lateral stability
of the cylinders; and great care was taken not to excavate too near the
bottom, but merely to loosen the ground round the cutting edge and to force
the cylinder down by weights. Stiff clay was sometimes used to prevent the
wet sand and gravel from being squeezed in from the outside. When the
cylinders had been sunk to the rock, and it had been dressed off to form a
level foundation, they were filled with concrete in the same manner as at
the Windsor bridge.
In sinking the cylinders of the main pier, much greater difficulties were
encountered than with those of the land piers, owing to large boulders and
pieces of timber being met with near the bottom. When still at some
distance from the rock, a length of one of these large cylinders cracked,
from its having met with an obstruction. Timber struts were then fixed

within it, until the obstacle was passed, when it was strengthened by a
strong wrought-iron hoop, and forced down to the rock.
In April 1851, when the greater number of the cylinders had been sunk,
it was apparent that, from delays due to the influx of water and other
causes, some of them could not be completed by the time that the
superstructure would be ready. Mr. Brunel then decided to employ the
pneumatic method, and by means of this apparatus some of the remaining
cylinders were sunk. In the main pier four auxiliary columns, formed of 7-
feet cylinders, were placed close to the others. They were connected to the
8-feet cylinders by strong brackets, and supplied a great additional bearing
surface. Any slight inaccuracy of position in the cylinders was corrected by
adjusting cones at the level of the ground; on these cones 6-feet cylinders
were built up to the level of the railway.
The depth to which the cylinders were sunk and their position are shown
in fig. 3, Pl. IV. From this drawing also the general form of the
superstructure will be understood.
The bridge is for two lines of way; each line is carried between two
longitudinal girders 7½ feet deep, of the section given in the woodcut, fig.
11 (p. 208). Each girder has a triangular top flange with a plate iron vertical
web, and a slightly curved plate for the bottom flange. The roadway girders
over the three land spans of 100 feet are in one piece, and are therefore
continuous girders, 300 feet long, supported at two intermediate points.
Those across the main span are also 300 feet long, and are supported by the
main truss.

PLATE IV
IRON BRIDGES

[Larger view]
[Largest view]

The truss for each line of way consists of two suspension chains, one on
each side of the roadway, hung from either side of the ends of a horizontal
circular tube, arched slightly for the sake of appearance, which rests on
piers rising about 50 feet above the level of the rails. The pier at the land
end is of masonry, and the upper part of the middle pier is of cast iron,
resting on the cylinders already mentioned. Each pier has two archways for
the trains to pass through. The chains carry the roadway girders at four
points, and the tube is supported at two intermediate points in its length by
upright standards resting on the chains. Thus, while the weight of the
structure is supported somewhat in the same manner as in a suspension
bridge, the inward drag of the chains is resisted by the tube. To prevent the
framework from being distorted by unequal loading, it is made rigid by
diagonal chains connecting the upper and lower ends of the two upright
standards.
The main truss may be described as an inverted queen truss. The tube
which has to resist the compressive strain due to the inward pull of the
chains is 9 feet in diameter, and is made of boiler plate ¾ and ⅝ of an inch
thick, stiffened at intervals by diaphragms. The chains are like those of
suspension bridges, each formed of 12 and 14 links alternately, these being
10 inches deep, and varying from ¾ to 11/16 of an inch thick.[101]

At the ends of the tube, where the chains are connected to it, there are
several thicknesses of plate, between which the links of the chains are
introduced, and a round pin, 7 inches in diameter, passes through both
plates and links. The strain is thus conveyed from the chains to the ends of
the tube.
Though the trusses for the two lines of way are completely distinct, the
tubes are braced together horizontally, to increase their stiffness sideways.
The woodcut (fig. 11) represents a transverse section of the truss for one
line of way, and shows the circular tube with the internal diaphragms, the
upright standards which support it, the roadway girders, and the chains.
In consequence of the great depth of the
truss, which is about 50 feet, or one-sixth of the
length, the strains on the several parts are
comparatively small for such a large span.
The weight of wrought-iron work in each of
the trusses of the main opening is 460 tons,
inclusive of the longitudinal and cross girders,
which weigh 130 tons.
At the points where the roadway girders are
intersected by the inclined chains, they are not
fixed to the chains, but rest upon them, rollers
and saddles being placed between; and at the
ends of the short horizontal links, in the middle
of the span, there are screws for adjusting the
level of the girders.
These arrangements were made in order that
the roadway girders might not be strained by the
slight alteration in the form of the truss which
takes place when a load comes on the bridge.
The continuous roadway girders were, in the case of the large span,
supported at six points, and in those over the three land spans at four points.
As the strains on continuous beams, supported at so many points, had not at
that time been fully investigated, Mr. Brunel had the subject carefully
enquired into both by calculation and experiment, and was thus enabled to
proportion the section of the girders to the strains at each point in their

length. Some account of this investigation is given in the note at the end of
this chapter.
As soon as the ironwork for the first truss was completed, it was put
together parallel to the river bank close to the site of the bridge. The ends
were supported on temporary piers, and the structure was uniformly
weighted with a load of 770 tons, or 2¾ tons per foot run. In unloading it,
the weight was taken off from one end of the truss, so as to test its strength
when unequally loaded. The testing having been satisfactorily completed,
the truss was taken to pieces, and preparations were made for erecting it.
It was necessary that the river traffic should not be interrupted for any
long period; this circumstance materially influenced the nature of the design
of the superstructure, which was such that no scaffolding was required in its
erection, nor was there any interference with the navigation for more than a
single tide. The truss was made so that it could be divided into parts, each
of which could be lifted separately and quickly. For the operation of lifting
Mr. Brunel determined to use chain purchases worked by crabs.[102] The
tube was temporarily stiffened by portions of the main chains, arranged so
as to form a truss. With this assistance it was able to carry its own weight
when suspended by the two ends.
The preliminary operation of slewing the tube to its position on a
platform at right angles to the river, was a work requiring a good deal of
careful contrivance. When this had been accomplished, a pontoon,
consisting of six wrought-iron barges, was placed opposite the end of the
tube, and all was ready for floating it across the river.
The floating took place on Thursday morning, April 8, 1852. The tube
had been rolled forward on two trucks till its end overhung the pontoon;
and, as the tide rose, the pontoon floated with the end of the tube resting on
it. In order to guide it in a straight line across the river, hawsers were
attached to points on the bank up and down the stream, and were led to
crabs on the pontoon, so that by hauling on either hawser the tube was kept
in its right course. As spring tides at Chepstow rise 40 feet, there is a rapid
current except for a very short time.
The operation of drawing the tube across was commenced at a little after
nine o’clock, and by a quarter to ten the pontoon had reached the other side
safely, and the tube spanned the river. All proceeded with perfect quiet and
regularity under the management of Mr. Brunel, who was assisted by Mr.

Brereton and Captain Claxton. As soon as the pontoon reached the further
shore, the chains of the lifting tackles were attached to the tube. The tube
was lifted in the course of the day to the level of the railway, and afterwards
to its place on the top of the piers, when the suspension chains and the rest
of the truss were attached to it. The bridge was opened for a single line of
way on July 14, 1852. The second tube was floated in a similar manner to
the first, and the bridge was completed shortly afterwards.
The total cost of the Chepstow bridge was 77,000l.[103]

The Royal Albert Bridge, which carries the Cornwall Railway across the
River Tamar at Saltash, is the last and greatest of Mr. Brunel’s railway
works.
A railway into Cornwall, crossing the river Tamar, was proposed as early
as 1844. Mr. Brunel at one time thought of carrying the trains across on a
steam ferry similar to those which had been successfully introduced by Mr.
Rendel.
In 1845 a company was formed and an application made for an Act to
construct the railway either with a steam ferry at Torpoint or by a bridge at
Saltash. The latter plan was sanctioned by Parliament.
The height of the line shown on the section at the crossing of the Tamar
was 80 feet above high water. The Admiralty, however, required that this
height should be increased. No further steps were taken till the beginning of
1847, when some preliminary borings and sections were made, in order to
prepare definite plans for the bridge. The facts then ascertained were so
encouraging as to strengthen Mr. Brunel in his opinion that the difficulties
to be encountered would not be found greater than had been anticipated.
The river at Saltash is 1,100 feet wide, with a depth in the middle of
about 70 feet at high water. It had at first been intended to construct the
bridge with one span of 255 feet, and six of 105 feet, with superstructures
of timber-trussed arches.[104] In compliance with the requirements of the
Admiralty, the design was altered to two spans of 300 feet, and two of 200
feet, with a clear headway of 100 feet. This arrangement would have
required three piers in deep water. Mr. Brunel subsequently decided to have
only one pier in deep water, and to have two spans of 465 feet each. It was
afterwards found that these could be reduced to 455 feet.[105]

Twenty years before, while engaged with his father on the Thames
Tunnel, he had conceived the idea of working under a diving-bell of great
dimensions. Sir Isambard approved of the suggestion, and thought of
applying it in sinking the shafts of the Tunnel. Drawings were prepared, but
the circumstance of a patent for a similar idea having been taken out by
Lord Cochrane partly deterred him from carrying out the project, though
some sketches were afterwards made for constructing a lighthouse by
means of this arrangement. When the construction of the Cornwall Railway
had to be considered, Mr. Brunel thought that his old idea would be
applicable to the difficulties to be encountered at Saltash.
Although the plan of using a large diving-bell was one which was nearly
certain to be successful, Mr. Brunel thought it probable that a large cylinder
of wrought iron could be constructed to serve as a coffer-dam, and that after
sinking it through the mud, the bottom edge might be sufficiently water-
tight to admit of the water being pumped out, and the masonry of the pier
built in the ordinary manner.
A trial cylinder, 6 feet diameter and 85 feet long, was made, partly to
ascertain whether or not this plan was practicable, but mainly for the
purpose of thoroughly examining the site of the centre pier, where the
surface of the rock was 80 feet below high water.
A strong framework was fitted on two gun-brig hulks, with powerful
tackle for lowering and raising the cylinder. After it had been lowered to the
bottom, five borings were taken within it, reaching through the mud to the
rock. The cylinder was then shifted and similar borings made.
The positions of the borings, one hundred and seventy five in all, were
carefully recorded; and thus a minute and accurate survey was obtained of
the surface of the rock. The site of the pier was afterwards determined by
means of a model constructed from these observations. In January 1849,
when sufficient information had been obtained, the water was pumped out
of the trial cylinder, and the mud excavated down to the rock. A short piece
of masonry was then built, to demonstrate the practicability of building a
pier in such a situation.
The expenditure of the Company for works of all kinds was shortly
afterwards curtailed as much as possible, and no further progress was made
for upwards of three years. However, information had been gained which
proved that a masonry pier could be built in the middle of the river, on a

good rock foundation which was there covered by a thickness of about 16
feet of mud.
During the suspension of the works, all the plans were revised, with the
view of reducing the first cost wherever practicable; and Mr. Brunel
decided not to make the bridge for a double line, even if there were money
forthcoming to do so. His reason for this is given in the following report to
the Board of Trade, made in 1852:—
This bridge had been always assumed to be constructed for a double line of railway as well as the
rest of the line. In constructing the whole of the line at present with a single line of rails, except at
certain places, the prospect of doubling it hereafter is not wholly abandoned, but with respect to the
bridge it is otherwise.
It is now universally admitted that when a sufficient object is to be attained, arrangements may
easily be made by which a short piece of single line can be worked without any appreciable
inconvenience.... This will make a reduction of at least 100,000l.

In the summer of 1852 the designs of the bridge were matured, and by
the beginning of 1853 the Admiralty had approved of them; the work of
constructing the great cylinder for the centre pier was then commenced.
It was determined to provide for the possibility of having to employ the
pneumatic process. The cylinder had a diameter of 35 feet at the bottom,
and about 20 feet above the lower end of it a dome was made to form the
roof of the diving-bell; from the centre of the dome rose a tube 10 feet in
diameter to the level of the top of the great cylinder. As a diving-bell of this
size, under 80 feet of water, might have proved unmanageable, an annular
space, forming a gallery or jacket of 4 feet in width and 20 feet high, was
formed round the inner circumference of the bottom of the cylinder below
the dome. This annular space was divided by radial vertical partitions into
eleven compartments, and was connected at the top by an air-passage with a
6-foot cylinder, which was placed eccentrically inside the 10-foot cylinder
already mentioned, and served as a communication between the outside and
the annulus. On the top of the 6-foot cylinder were placed the air-locks of
the pneumatic apparatus which had been used at Chepstow. Thus air might
be pumped into the annular space, the water expelled, and the work carried
on without having to use air pressure under the whole of the dome. In that
part of the 10-foot cylinder which was not occupied by the 6-foot cylinder a
powerful set of pumps were fixed to keep down the water in the central
space, and diminish the pressure under which the men worked, thus
utilising whatever advantage could be gained from the great cylinder acting

as a coffer-dam. As it had been ascertained that the surface of the rock
dipped to the south-west to the extent of about 6 feet in the width of the
pier, the bottom of the cylinder was made oblique, so as to fit the surface of
the rock. These arrangements are represented in the transverse section of the
great cylinder (Pl. V. p. 218).[106]
The great cylinder, having been constructed on the river-bank, was
moved down to low water on launching-ways, and floated off by the rising
tide. Guided between four pontoons, it was finally sunk in correct position
in June 1854.
Some delay in penetrating the mud was caused by a bed of oyster shells,
which had to be cut through by one edge of the cylinder. In consequence of
some irregularities of the surface of the rock, the cylinder at first deviated
considerably from an upright position; and it was necessary to use the
pneumatic apparatus to gain access to the rock, and excavate it. The height
of the annulus below the dome was such that it was not quite filled by the
mud when the cylinder rested on the bottom. The work of getting the mud
out of the annular space was much facilitated by the division of it into
compartments.
By February 1855, the cylinder had been sunk to its full depth in an
upright position, and it then rested everywhere on the rock, its lowest point
being 87 feet 6 inches below high water.
Much trouble was given by a spring of water issuing out of a fissure in
the rock, in one of the compartments, but the flow was stopped by driving
close sheet piles into the fissure. The rock in the annulus was dressed, and
the space filled by a ring of granite ashlar masonry which was built to a
height of about 7 feet all round. The state of the work at this time is that
represented in the section of the cylinder, (Pl. V. p. 218).
The rock consisted of greenstone trap, so hard that tools could with
difficulty be got to work it. When the ring of masonry was completed, it
was expected that the bottom might be sufficiently water-tight to act as a
coffer-dam, and allow of the mud being taken out from the central part of
the cylinder, below the dome. But the pumping power was not at first
sufficient for this purpose, and it was thought that it would be necessary to
employ the pneumatic process in this space also.
However, by rapid and incessant pumping the water was lowered so as to
allow of the mud and rock being excavated, and the masonry in the central

space built without having again recourse to the use of air pressure. The
leakage water was conveyed to two wells, formed of cast-iron pipes built
into the masonry, from which the water was pumped. The inner plates of the
annulus were cut out, and the work in the centre which consisted of granite
ashlar set in cement was thoroughly bonded into the ring of masonry
already built. When the work was carried up to the level of the dome, both
the dome and the internal 10-foot cylinder were cut out and removed. When
the building had been carried up some height, the pump wells were filled
with cement concrete, and the influx of water stopped. Finally, about the
end of 1856, when the masonry was completed to the cap of the pier, the
upper part of the great cylinder was unbolted and taken ashore, it having
been made in two halves with that object. Thus the most difficult part of the
undertaking was successfully completed.[107]
The centre pier of the Saltash bridge is, like many great engineering
works, out of sight, and little regarded by any but professional men. The
rest of the bridge forms a striking feature in a beautiful landscape, and its
appearance is well known.
The whole length of the bridge is about 2,200 feet, and is divided into
two great spans over the river of 455 feet each and seventeen side spans,
varying from 70 to 90 feet, which are on sharp curves. The piers of the side
spans, as well as the two large piers carrying the land ends of the main
trusses, are of masonry. The masonry of the centre pier is 35 feet in
diameter, and is carried up about 12 feet above high water level. On it stand
four cast-iron octagonal columns, rising up to the level of the railway. The
piers which support the ends of the great trusses are constructed with arched
openings, through which the trains pass.
The transverse elevation of the centre pier (Pl. V.) shows the octagonal
columns connected by cast-iron open-work, and the arched opening. The
upper part of the centre pier is a cast-iron standard, and that of the land
piers is of masonry cased with cast iron.[108]
The elevation shows the great height of the structure, the rails being 190
feet and the highest part of the truss 260 feet above the lowest point of the
foundations.
The railway is carried over each of the smaller openings between two
longitudinal girders, and over the main spans it is carried between similar
longitudinal girders, which are suspended at intervals from the main truss.

PLATE V
THE ROYAL ALBERT BRIDGE

[Larger view]
[Largest view]

Each truss consists of a wrought-iron oval tube, which forms an arch,
and of two suspension chains,[109] one on either side of the tube, connecting
its two ends. The rise of the arched tube above its abutments on the top of
the piers is the same as the fall of the suspension chains below the same
level. At eleven points in the length of the truss the chains are connected to
the tube by upright standards, which are braced together by diagonal bars,
in order to resist the strains due to unequal loading. The roadway girders are
suspended from the truss at the upright standards already mentioned, and at
an intermediate point between each of them.
The truss has the great depth of 56 feet in the centre; this conduces
materially to the economy of the construction, as it diminishes the strain
upon the principal parts, the tube and the chains, and so enables them to be
made of smaller dimensions.
The woodcut (fig. 12) is a transverse section in the centre of the truss,
showing the oval tube, the chains, the upright and standards, the roadway
girders.
The tube is made oval in section with the greater diameter horizontal, in
order that it may have stiffness sideways under the compressive strain, and

that the main chains may hang vertically at such a
distance as to leave room for the roadway between
them. The tube is 16 feet 9 inches broad and 12 feet 3
inches in height. Each chain consists of two tiers of
links, each tier formed of 14 and 15 links alternately.
These are 7 inches deep and about 1 inch thick. The
arrangements of the ironwork of the tube and its
connections with the main chains are generally
similar to those at Chepstow.
The truss may be described as a combination of an
arch and a suspension bridge, half the weight being
placed on the one and half on the other, the outward
thrust of the arch on the abutments being
counterbalanced by the inward drag of the chains.
The mechanical arrangement of the Saltash truss is
similar to that of the one at Chepstow.[110] The tube,
resting on standards, the railway passing beneath, the
suspension chains hung from either side of the tube,
the upright standards, and the diagonal bracing are
common to the two structures.
The difference in the form of the two trusses is
principally the result of the difference in the
circumstances attending the construction of the bridges at Chepstow and
Saltash. The design of the Chepstow truss was chiefly determined by the
necessity of lifting up the separate parts of it under conditions of peculiar
difficulty; while at Saltash the mode of floating and lifting the
superstructure had great influence in the preparation of the design.
On Plate V. (p. 218) is given an elevation of one span of the Saltash
bridge, and a general elevation on a smaller scale of the whole bridge.
The total weight of wrought ironwork in the superstructure of each span
is 1,060 tons.[111]
The trusses at Saltash were not lifted in parts, as at Chepstow; for, as the
river was divided by the centre pier into two openings, one of them could be
left clear for the navigation, and each truss, with its roadway girders
attached, could be raised to its position slowly and in one piece. The trusses
were constructed parallel to the river on the Devonshire side, close to the

site of the bridge. When the truss for the Cornwall or western span was
completed, temporary piers were erected to support the ends, and the
scaffolding having been removed, the roadway was loaded with 1,190 tons,
uniformly distributed.[112]
This test having proved satisfactory, preparations were made for floating
the truss. Docks were made underneath it near the two ends, and in each of
these docks two iron pontoons were placed. Valves were then opened to
admit water, and the pontoons were allowed to sink on timbers prepared to
receive them.
Upon each pair of pontoons was erected an elaborate framework of
timber to carry the weight of half the truss, or between 500 and 600 tons.
The framework consisted of stout timber props, some of them 40 feet long,
extending from the pontoon to the arched tube, and was attached to the tube
by iron suspension rods, so that when the operation of floating was
completed, the pontoons would be free to pass from underneath the truss.

Mr. Brunel had previously taken part in operations of this nature. When
Mr. Robert Stephenson was about to undertake the floating of the tubes of
the Conway and Britannia bridges, he asked his friends Mr. Brunel and Mr.
Locke to give him their assistance. They were present at all, or nearly all,
these difficult operations, and Mr. Brunel had an active share in the work,
especially in the floating of the first Conway tube. By Mr. Brunel’s advice
Mr. Stephenson had obtained the services of Captain Claxton to superintend
the nautical part of the work; and Captain Claxton was, as a matter of
course, with Mr. Brunel in a similar capacity at Chepstow and Saltash.
At Saltash fortunately there was not so swift a tide as there had been at
the Britannia and Conway floatings.
In order to haul the truss out, warps were laid from the pontoons to a
gun-brig hulk near the centre pier, and to a barge higher up the river. On this
barge were also placed ready for use the ends of four warps, leading to
capstans and crabs on board vessels moored at various points. To keep the
truss from being drifted up or down the river while being moved out, radius
lines were laid from the pontoons to moorings, with arrangements for
hauling in on them if required.
In order to ensure his directions being clearly understood and promptly
attended to, Mr. Brunel assembled a number of his assistants, one of whom

was placed as ‘Captain’ in each of the vessels containing the hauling
capstans, to superintend the men, and to execute orders. These orders were
given by signals.
It was most important that the attention of the captain should not be
diverted by looking out for the signals, and that there should be no chance
of a signal not being seen by him because he was attending to some other of
his duties. There was, therefore, in each vessel an assistant whose sole duty
it was to watch for the signals, to give the appropriate interpretation to the
captain, and to acknowledge the signal by a flag corresponding to that by
which it was given.
Mr. Brunel directed the operations from a platform in the centre of the
truss. The signals were given from a smaller platform immediately above,
and were made by red and white flags, held in front of black boards, which
were turned towards the vessel signalled to. Printed papers containing
instructions were distributed to all engaged; the signalling was carefully
rehearsed, as also was every other part of the operations which could be
tried beforehand.

September 1, 1857, was the day fixed for the floating. During the
morning, the men, about 500 in number, assembled at their stations on the
vessels and pontoons. Captain Claxton had command of the arrangements
afloat, and as a reserve force to act in any emergency several boats were
lent from H.M.S. ‘Ajax’ and the Dockyard. With Mr. Brunel were Mr.
Brereton and Captain Harrison, the commander of the ‘Great Eastern.’ Mr.
Robert Stephenson was expected, but a serious attack of illness prevented
him from being present.
At about one o’clock in the afternoon signals from the tops of the
temporary piers on which the truss rested, showed that the ends had been
lifted three inches clear. Mr. Brunel then gave the signal for the men in the
pontoons to haul on the warps, and the great structure glided slowly out to
the centre of the river. A pause was then made, while the warps which were
to swing the truss round into its place were being attached to the pontoon
which was farthest from the centre pier. When this was done, the different
ropes were hauled upon in obedience to signals, so as to keep the other
pontoon close to the centre pier, upon which, as a pivot, the truss swung
round in a quarter circle till it occupied the whole of the western half of the

river, and was brought close to its appointed resting-place. It was finally
adjusted to its exact position by strong tackles attached to the piers. Water
was then admitted into the pontoons; and, as the tide fell, they were allowed
to drift away, leaving the truss resting on the piers, the roadway girders
being but a few feet above the water.
The whole operation was conducted with the most perfect order and
regularity. The beauty of the scenery and the changing effect produced by
the truss in the various positions it assumed as it was being moved forward
and swung round into its place, rendered the operation as interesting to the
spectators as its results were satisfactory to Mr. Brunel and to those who
assisted him.[113]

In the task of lifting the truss, as well as in that of floating it, Mr. Brunel
had the great advantage of the experience gained at the Britannia Bridge.
There the piers were built first, and the tubes hauled up with link chains by
hydraulic presses placed on the tops of the towers. The design of the piers at
Saltash did not allow of this plan being adopted, and they were built up
under the truss as it was lifted. Under each end of the truss were three
hydraulic presses; the two outside presses combined, or the middle one by
itself, were sufficient to lift the weight. Mr. Brunel had also at first intended
to have strong screw-jacks, which were to be kept screwed up underneath
the truss, and so to support the weight, if by any accident the presses failed.
A modification of this plan was adopted; the rams of the presses had a
screw thread cut on them, and a large nut on each was kept screwed up hard
against the top of the press as the ram emerged from it. As an additional
precaution, timber packing, in thin layers, was placed in the space between
the completed portion of the pier and the end of the truss as it was lifted.
Great care was thus taken to guard against any mishap.
The tube was lifted 3 feet at a time at each end. The operation went on
slowly, in order to allow the masonry of the land pier to set after it had been
built up underneath the truss. The work was carried on with great system
and care under the immediate superintendence of Mr. Brereton. Mr. Brunel
was only able to be present during one of the lifting operations, as he was
then engaged in the launch of the ‘Great Eastern.’

By July 1858, the first truss had been lifted to its full height, and the
second truss was ready for floating. The arrangements were generally
similar to those on the previous occasion; the course, however, to be
traversed by the pontoons was more intricate than on the previous occasion,
as the land pier on the Devonshire side of the river, over which the first
truss had passed, had been built up to receive the end of the second.
This truss had, therefore, to be moved first outwards till the pontoons
were clear of the docks, then it had to move endways up the river, and to
swing round into position. Mr. Brunel was obliged to remain abroad from
ill-health, and Mr. Brereton conducted the operations. Although the weather
was not favourable, and the wind high, the truss was safely landed on the
piers; and was afterwards raised in the same manner as the first one.[114]
The general elevation, Plate V., shows the proportions of the bridge. On
the Devonshire side, the side spans pass over fields, and on the Cornwall
side over the town of Saltash.
The general effect of the bridge is in no way heightened by an
expenditure of money on architectural ornament; for, with the exception of
a few unimportant mouldings, the bridge is absolutely unadorned. The total
cost was 225,000l.—a very moderate expenditure, especially when the
difficult work at the centre pier is taken into account. This result is due not
only to the careful manner in which all the details of the design were
prepared, but also to the great attention given throughout to the
construction.
His Royal Highness the Prince Consort, as Lord Warden of the
Stannaries, permitted the bridge to be called the Royal Albert Bridge, and
consented to open it in person. The ceremony was performed on May 3,
1859. Mr. Brunel was compelled to be absent on the Continent, for the sake
of his health, and was represented on the occasion by Mr. Brereton.
After Mr. Brunel’s return to England, he paid a hurried visit to the
Cornwall Railway, and, for the first and last time, saw in its completed state
the great work on which he had expended so much thought and care.

NOTE, (pp. 182, 194, 209).
Experiments on Matters connected with Bridge Construction.

No account of the structures designed by Mr. Brunel would be complete
without a reference to the elaborate care he always took, wherever it was
practicable, to satisfy himself by experiment of the qualities of the materials
employed, and of the correctness of the principles followed. It would not
here be possible to give a detailed record of all his experiments, but an
account of some of the methods employed by him will be interesting.
Some of the larger of Mr. Brunel’s experiments on cast and wrought-iron
girders have already been mentioned.[115] He scarcely ever made any large
girder or framework without having it fully tested, and he made extensive
and elaborate experiments, most of them on a very large scale, on the
strength of some of the materials and component parts of his different
structures.
Among the large scale experiments tried by Mr. Brunel, were those on
the compressive strength of yellow pine-timber, which were made at Bristol
in 1846, and were on specimens from 10 to 40 feet in length, and from 6 to
15 inches square. A framework of four upright pieces of whole timber,
nearly 50 feet high, contained four strong bars of wrought iron, placed
vertically, and attached at their lower ends to the cylinder of a hydraulic
press. Along these bars, a casting could be moved, and fastened at different
heights by keys, in such a manner as to have its under-surface, which was
planed, perfectly horizontal. The ends of a specimen having been made
exactly square to its length, it was put in this apparatus, with the upper end
bearing against the lower surface of the movable casting, and the lower end
resting on the top-surface of the ram of the hydraulic press, which was also
planed and adjusted so as to be horizontal. The keys, which attached the
movable casting to the bars, were now driven tight, and the pump of the
press worked, weights being placed on the end of the lever, to correspond
with increments of pressure on the ram. These weights were added
gradually, until the specimen gave way. The accuracy of this mode of
measuring the pressure was tested by direct loading of the ram with rails,
which was repeated several times during the course of the experiments, so
as to guard against any change in the amount of friction of the press. For
each increment of weight, the compression of the specimen was measured
on its four faces, and its deflection, or amount of bending, on two adjacent
faces. The transverse stiffness of long specimens was also tried, by
supporting them at each end, and loading them in the middle. The deflection
in the middle thus observed corresponded very closely with what might

have been expected from the observations on the direct compression; and
from the constants so obtained, the strength of those specimens, whose
length was very great as compared with their transverse dimensions, could
be obtained by Euler’s theory, but for the stouter specimens the strength per
square inch was found to be nearly constant. From these experiments, a
complete practical knowledge of the properties of yellow pine timber, when
subjected to end pressures, was obtained, knowledge new at the time, and
almost essential to Mr. Brunel in designing the many viaducts which he
afterwards constructed.
Mr. Brunel also made experiments on the strength of pine timber when
exposed to pressure on the side or at right angles to the fibre. By this means
he determined the area which it was desirable to provide for the washers of
bolts, and the weight which might safely be placed on transverse timbers or
sills of viaducts.
Mr. Brunel’s experiments on riveting were also important. Most of these
were made with specimens 20 inches wide, and half an inch thick. They
were compared with specimens of solid iron, of the same quality and
thickness as the riveted specimens, and also the same width minus the rivet
holes, so as to have equal efficient sectional areas. Double covering plates
and double riveting were used in all cases, the variation being in the widths
of the covering plates, and the number and arrangement of the rivets. The
experiments were continued until thirty in all had been made, and the
strongest form of joint was considered to have been arrived at.
In connection with the lifting of the parts of the Chepstow Bridge, an
elaborate series of experiments was made on ropes, chains, and wire-rope,
so as to ascertain which of these it was desirable to employ, as possessing
the greatest advantages. The experiments made were of two kinds, one to
determine the absolute strength of the specimen when subjected to a straight
pull, and the other to observe what took place when it was worked over a
sheave. In the first set the specimen was held at each end in the jaws of a
pair of wrought-iron clamps, which were tightened up by means of screws.
One of the clamps was attached to a fixed beam, and from the other was
suspended a large cylindrical tank, which was gradually filled with water
until the specimen gave way, the breaking strain being the weight of the
tank and water. This weight was ascertained by actual weighing with a
steelyard when the water in the tank was at different heights. Observations
on the extension, shrinkage of the circumference, and change in the pitch of

the spiral of the rope were made with different loads, and the strength of a
sufficient number of the yarns of which the rope was composed was tried to
ascertain the loss of strength by combining the yarns into a rope. In the
second set the specimen, clamped as before, was passed over a sheave, the
axle of which rolled horizontally on planed cast-iron plates, in order to
diminish friction. To each clamp was attached a cylindrical iron tank. Water
being admitted to the highest tank until downward motion commenced, its
influx was stopped, and the tank descended, the other one rising. Water was
then admitted to the now highest tank until motion again commenced, and
this process was repeated until the specimen gave way, the tanks getting
fuller of water at each movement, at which times the difference of weight of
the two tanks was observed. This, minus the slight friction of the apparatus,
represented the rigidity of the rope. The extensions were observed as in the
first set of experiments.
The specimens consisted of hemp, manilla, shroud laid and hawser laid
ropes, from 8 to 10 inches in circumference, round and flat wire ropes, and
chains of different sizes of about the same strength as the ropes. The
sheaves also were of different diameters. These experiments resulted in Mr.
Brunel deciding to use chains for lifting the bridge, and this mainly from
the circumstance that chains work more satisfactorily over a sheave than
either hemp or wire ropes.
Some small scale experiments made by Mr. Brunel are deserving of
notice. These were made to verify calculations on the longitudinal girders of
the Chepstow truss, which are virtually continuous beams of five unequal
spans. It was desirable to test the results of analysis by experiment, in order
to be assured that no errors had been committed in its application. Mr.
Brunel accordingly devised the following simple form of experiment for
this purpose. A deal rod, exactly half an inch square and 38 feet long, quite
free from knots, was supported on props of equal height, above the
perfectly horizontal and planed surface of a large beam of timber. The props
were placed so as to correspond relatively to the actual spans, and the rod
was loaded uniformly by means of a chain. It was thus bent into an elastic
curve, the ordinates of which were very carefully measured, at every foot
along the length, by a finely divided scale and magnifier. The pressure on
each prop was also determined, by removing any particular one, and
suspending the point of the rod immediately over it to a steel-yard, the
weight being observed when the point of the rod was exactly at the same

level as before the prop was removed. The obvious condition, that the sum
of the pressures on the props should be equal to the weight of the rod and its
load, furnished a satisfactory means of testing the results of these
weighings. The rod being turned over on each of its four sides, the
experiments were repeated, and the average taken, in order to eliminate the
effects of initial curvature, or of unequal elasticity. Diagrams of the elastic
curves were then made, showing the correspondence of theory with
experiment, and this was so close as to leave no doubt that a true knowledge
of the nature of the strains had been arrived at. One of these diagrams is
given by Mr. Edwin Clark in his work on the ‘Britannia and Conway
Tubular Bridges,’ vol. i. p. 462.
By modifications of the plan Mr. Brunel adopted in this experiment, the
strains on continuous beams of varying section may be ascertained with
considerable accuracy.

CHAPTER VIII.

STEAM NAVIGATION. THE ‘GREAT WESTERN’ STEAM-SHIP.

A.D. 1835—1847. ÆTATIS 30—42.

INTRODUCTION TO THE CHAPTERS ON STEAM NAVIGATION—
FORMATION OF THE GREAT WESTERN STEAM-SHIP COMPANY—
COMMENCEMENT OF THE BUILDING OF THE ‘GREAT WESTERN’—
REPORT ON SELECTION OF THE BUILDERS OF THE ENGINES (JUNE
18, 1836)—STATEMENTS OF DR. LARDNER ON THE PROBABLE
FAILURE OF A LINE OF STEAM-SHIPS BETWEEN ENGLAND AND
AMERICA—VOYAGE OF THE ‘GREAT WESTERN’ TO LONDON—
COMPLETION OF THE ENGINES—HER RETURN TO BRISTOL—FIRE
ON BOARD AND ACCIDENT TO MR. BRUNEL—VOYAGE TO NEW
YORK—COMPARISON BETWEEN THE PERFORMANCES OF THE
‘GREAT WESTERN’ AND THE ‘SIRIUS’—SUBSEQUENT HISTORY OF
THE ‘GREAT WESTERN’—NOTE: DIMENSIONS OF THE SHIP AND
ENGINES.

IT will readily be conceded that Mr. Brunel’s railway works, which have
formed the subject of the five preceding chapters, would have given him
ample employment for the thirty years of his professional life.
Nevertheless, during almost the whole of that period—namely, from
1835, the year of the passing of the Great Western Railway Bill, to his death
in 1859—he was also engaged in the accomplishment of undertakings
which had for their object the systematic development of Ocean Steam
Navigation.[116]
The ‘Great Western,’ the first steam-ship which made regular voyages
across the Atlantic, the ‘Great Britain,’ the first large iron steam-ship, and
the first large ship in which the screw propeller was used, and, lastly, the
‘Great Eastern,’ were Mr. Brunel’s works, built under his direction, in the
midst of his other engrossing occupations, and at the sacrifice of his health
and life.
The history of these projects will contain records of many
disappointments as well as of success; for no great and novel undertaking
can be perfected at once and without changes of plan and arrangement. As
engineer to the Companies which built these steam-ships, Mr. Brunel

advised the adoption of measures strongly in opposition to current popular
opinion, and far bolder and more daring than even his recommendation of
the broad gauge and the atmospheric system. The results obtained have
verified his calculations, and the conclusions he sought to establish are now
so generally accepted that it is difficult to believe that they were ever
questioned. No one now has any doubt that large vessels can with safety be
built of iron, or that the screw propeller can be advantageously employed in
ships of war and the mercantile navy; no one can now deny that it is
practicable for steam-ships to make long voyages across the ocean with
regularity and speed.

A detailed account will now be given of the ships whose performances
first demonstrated the truth of these propositions.
Although the ‘Great Western’ was the first steamer which was built for
regular voyages between Europe and America, the first attempt to use steam
in the direct voyage across the Atlantic was made by an American ship of
300 tons burden, called the ‘Savannah,’ and built at New York. Her engines
were of small power, with paddles made to ship and unship. She made only
two voyages to and from Europe: in the first of these she left the port of
Savannah on May 25, and anchored at Liverpool on June 20, 1819.
No further advance in Ocean Steam Navigation seems to have been
attempted until 1835. In the October of that year, at a meeting of the
Directors of the Great Western Railway Company, at Radley’s Hotel, in
Bridge Street, Blackfriars, one of the party spoke of the enormous length, as
it then appeared, of the proposed railway from London to Bristol. Mr.
Brunel exclaimed, ‘Why not make it longer, and have a steamboat to go
from Bristol to New York, and call it the “Great Western?”’ This suggestion
was treated as a joke by most of those who heard it; but at night Mr. Brunel
and Mr. T. R. Guppy, one of the Directors, talked it over, and afterwards
consulted three of the leading members of the Board—Mr. Scott, Mr.
Pycroft, and Mr. Robert Bright. They took up the idea warmly, and a
committee was formed to carry out the project.
As a preliminary measure, Mr. Guppy and Captain Christopher Claxton,
R.N., made a tour of the great ship-building ports of the kingdom, in order
to collect information. The results of their inquiries were embodied in a
report, dated January 1, 1836, which describes at great length the

advantages to be gained in large vessels. The manuscript was submitted to
Mr. Brunel previously to its publication, and he inserted the following
passage:—
The resistance of vessels in the water does not increase in direct proportion to their tonnage. This
is easily explained; the tonnage increases as the cubes of their dimensions, while the resistance
increases about as their squares; so that a vessel of double the tonnage of another, capable of
containing an engine of twice the power, does not really meet with double the resistance. Speed
therefore will be greater with the large vessel, or the proportionate power of the engine and
consumption of fuel may be reduced.

This was an important addition to the report, for it enunciates the
principle which governed Mr. Brunel in determining the dimensions and
power, not only of the ‘Great Western,’ but also of the ‘Great Britain’ and
‘Great Eastern’ steam-ships.
Immediately after the publication of this report a Company was formed
in Bristol called ‘The Great Western Steam-Ship Company,’ Mr. Peter Maze
being the Chairman, and Captain Claxton the Managing Director. Captain
Claxton’s exertions in the service of the Company from its formation to its
dissolution were unremitting and invaluable. He was also, from the date of
Mr. Brunel’s first connection with Bristol, one of his most intimate friends,
and his confidential adviser on all points on which nautical experience was
of value.[117]
Mr. Patterson (an eminent ship-builder of Bristol) was selected to
superintend the building of the first ship, under the direction of a ‘Building
Committee’ consisting of Captain Claxton, Mr. Guppy, and Mr. Brunel.
Whenever railway business called Mr. Brunel to Bristol, which at this time
was at least once in every week, the Committee and Mr. Patterson used to
meet at the office, or at Captain Claxton’s or Mr. Guppy’s house, and often
sat far into the night discussing the details of the design of the ship.[118]
One of the most important questions which occupied Mr. Brunel’s
attention was the selection of the builders of the engines. Tenders were
invited; and on receiving them, he addressed the following report to Captain
Claxton, the Managing Director:—
June 18, 1836.
In considering the three tenders for the supply of marine engines for your first vessel, which you
have submitted to me for my opinion, I have assumed that the interests of the company are
paramount, and that all feelings of partiality towards any particular manufacturer or any local interest
must yield to the absolute necessity, in this the first and the boldest attempt of the kind yet made, of
not merely satisfying yourselves that you will obtain a good engine, but also of taking all those

means of securing the best which in the eyes of the public may be unquestionable. In this view of the
case, if you agree with me, I think you will consider that, provided the prices are fair individually, the
relative amount of the tenders is a secondary consideration.
I assume, also, that the high respectability of all these parties would ensure equally from either
the best materials and workmanship, and I shall confine myself simply to pointing out a few of the
conditions peculiar to the engines which you require, and the means which the different parties have
of complying with these conditions.
I need hardly remind you that, owing to the lateness of the season, you will require that the vessel
should be prepared to run her first voyage almost immediately after the engines are fixed. You will
remember, also, that it will be the longest voyage yet run; that in the event of unfavourable weather a
total failure might be the result of the engine not working to its full power, or consuming too great a
quantity of coals—a very common occurrence with engines apparently well made, after six or eight
days’ constant work; and, lastly, that the future success of the boat as a passenger ship—nay, even of
the company’s boats generally, and, to a great extent, and for some time, the reputation of Bristol as
an American steamboat station, may depend upon the success of this first voyage. It is indispensable,
therefore, to secure as far as possible a machine which shall be perfect in all its details from the
moment of its completion. There may be time for a few trials for ascertaining the fact of its
completion, but there will be none for effecting any alterations should they be found necessary, or for
making any experiments. The machinery which you require to be so perfect is by no means an
ordinary steam-engine.
Marine engines of 80 or 90, and even some of 100 horse-power, are mere models on a large scale
of the ordinary-sized engines. Engines of 160 or 180 horse-power each would be unmanageable
without many material modifications in the details; the arrangement must be different, and, as the
strength of materials remains the same, the proportionate dimensions of the parts must be modified.
Many contrivances of this description have been introduced into the large engines of 110 horse-
power each made for the Navy. From 110 to 160 is still another and a very great stride. Those who
have led the way in the first step are certainly the most likely to be aware of the difficulties of the
second, and to be able to appreciate them better, and be more prepared to overcome them than those
who have as yet only manufactured, however successfully, engines of the ordinary class. Of three
parties tendering.... Messrs. Maudslay have made by far the largest number, and have for some years
led the way in the introduction of the largest armed steamboats; and there can be no question as to the
fact that they are the oldest manufacturers of marine engines, that they are themselves the originators
of the greatest number of the improvements of the day, that they have made the largest engines yet
made, and the greatest number of large engines of all sizes; and, lastly, that they have the principal
supply of engines for the large war ships now used for the Navy, and have had hitherto the sole
supply of all above 70 horse-power. With these facts before you, it remains only for you to consider
how far you agree with me in the conclusion I have come to, and which I have no hesitation in
expressing—that I think you will be safest, in the peculiar case of the first ship, in the hands of the
parties who have had most experience, and that Messrs. Maudslay are those persons. Their price is, I
think, moderate.

This report was read by Mr. Brunel at a meeting of the Board,
summoned at his request; the Directors adopted his advice, and accepted the
offer of Messrs. Maudslay & Field, of Lambeth.[119]
The ‘Great Western,’ for so the ship was called, had not been long
commenced when a somewhat celebrated controversy arose, in which the

correctness of Mr. Brunel’s views was questioned by the late Dr. Dionysius
Lardner.
The circumstances which led to this discussion were as follows:—
The British Association for the Advancement of Science held its sixth
meeting at Bristol in August 1836; and, as Dr. Lardner was announced to
lecture on Transatlantic Steam Navigation, great interest was felt in Bristol
on the occasion.
After some postponement, he delivered his lecture on August 25, to a
crowded meeting of the Mechanical Section. The proceedings of the
Association unfortunately do not give any report of Dr. Lardner’s
observations; but, as in his latest work on the subject[120] he speaks in
commendatory terms of the report given in the ‘Times’ newspaper, that
account may be relied on as correct.
In the ‘Times’ of August 27, 1836, it is stated that in the course of his
lecture Dr. Lardner said,—
Let them take a vessel of 1,600 tons, provided with 400 horse-power engines. They must take 2⅓
tons for each horse-power, the vessel must have 1,348 tons of coal, and to that add 400 tons, and the
vessel must carry a burden of 1,748 tons. He thought it would be a waste of time, under all the
circumstances, to say much more to convince them of the inexpediency of attempting a direct voyage
to New York, for in this case 2,080 miles was the longest run a steamer could encounter: at the end of
that distance she would require a relay of coals.

There is no detailed report remaining of the animated discussion which
followed the lecture, and in which Mr. Brunel took part. He exposed several
errors in Dr. Lardner’s calculations, but failed to produce any effect upon
the majority of those present, who were powerfully impressed by the
lecturer’s dogmatic assertions.
Those assertions seem to have had a wide circulation beyond the walls
of the lecture-room; and if Dr. Lardner’s arguments were sound, and if
transatlantic steamers ought to have taken their departure from ‘the most
western shore of the British Isles,’ the enthusiastic advocate of a railway
scheme in Ireland might well exclaim,—
The promoters of this vast object stand forewarned of defeat. Dr. Lardner, who has bestowed a
great deal of pains in arguing the bearings of this undertaking, has pronounced it impracticable; and I
entirely agree with him in his conclusions. The effort, nevertheless, will be made; the genius of
English enterprise will hazard the consequences; and every honest spirit that shall hear of the brave
British crew which will embark upon that perilous expedition will feel his heart beating high for the
merchant-sailor, whom nothing can deter. He will sail; but, though dangers will encompass him, and
destruction appear, there is yet a hope for his ultimate success. Let us cheer ourselves with the

expectation that, as the exhausted mariner returns, he will fall in with the western shores of Ireland;
that, worn out and hopeless of home and comfort upon earth, the Shannon will win him to her
bosom; that, invited by the graceful sinuosities of that noble stream, and the rich and fertile lands
around, he will advance to this convenient and improving city; and as he rests within its walls that he
will exclaim, ‘This is the place from which I ought to have set out, for here have I returned with ease
and safety!’[121]

Dr. Lardner’s views are repeated in an article in the ‘Edinburgh Review’
for April 1837 (vol. lxv.); and in the report of the proceedings of the British
Association for 1836 (p. 130 of the proceedings of the sections), the reader
is referred to this article, apparently as a substitute for an abstract of the
lecture.
The following résumé is there given of the lecture:—
The conclusions at which he arrived were briefly these: that, in the present state of the steam-
engine as applied to nautical purposes, he regarded a permanent and profitable communication
between Great Britain and New York by steam-vessels making the voyage in one trip as in a high
degree improbable; that since the length of the voyage exceeds the present limits of steam-power, it
would be advisable to resolve it into the shortest practicable stages; and that, therefore, the most
eligible point of departure would be the most western shores of the British Isles, and the first point of
arrival the most eastern available parts of the western continent; and that, under such circumstances,
the length of the trip, though it would come fully up to the present limit of this application of steam-
power, would, nevertheless, not exceed it, and that we might reasonably look for such a degree of
improvement in the efficiency of marine engines as would render such an enterprise permanent and
profitable. (P. 119.)

Among other objections to long voyages the reviewer enumerates the
incrustation of boilers, and the choking of smoke flues; and then, with
reference to the quantity of fuel required, he proceeds:—
In proportion as the capacity of the vessel is increased, in the same ratio or nearly so must the
mechanical power of the engines be enlarged, and the consumption of fuel augmented.... It is
therefore demonstrable that, in the present state of steam navigation, if this voyage shall be
accomplished in one uninterrupted trip, the vessel which performs it must, whatever may be her
power and tonnage, be capable of extracting from coals a greater mechanical virtue, in the proportion
of three to two, than can be obtained from them by the combined nautical and mechanical skill of Mr.
Lang, the builder of the ‘Medea,’ and Messrs. Maudslay and Field.... That the passage from
Liverpool to New York cannot on any occasion be made in one run by a steam-ship we do not
maintain.... The average time of the outward voyage to New York is thirty-six days, and we say that
when the circumstances of wind and water are such that a sailing vessel would require that time to
make the passage, a steamer cannot make it without an intermediate supply of fuel. (Pp. 127, 139,
143.)

To sum up Dr. Lardner’s views in his own words written at about this
time,[122] ‘We have as an extreme limit of a steamer’s practicable voyage,
without receiving a relay of coals, a run of about 2,000 miles.’[123]

It will be seen from these extracts that the proposition Dr. Lardner laid
down as the basis of his ‘demonstration’ was, that the power of the engines
must be increased as the size of the vessel. Were this true his conclusion
would also be true—namely, that the capacity of a given vessel regularly to
accomplish a given voyage does not increase with the increase of size, since
the consumption of fuel is augmented in about the same ratio.
This assumption is directly opposed to the opinion held by Mr. Brunel,
and acted on by him in his recommendations to the Steam-Ship Company—
namely, that while the tonnage of a ship is increased as the cube of her
dimensions, the resistance is increased only about as the square.
This question was the main point at issue between Dr. Lardner and Mr.
Brunel; and the proposition which Mr. Brunel then asserted is at the present
time the basis of the calculations which determine the proportion between
the tonnage of a steam-ship and the length of voyage she has to perform
without a relay of fuel.

The history of the ‘Great Western’ steam-ship has been interrupted by
this examination of Dr. Lardner’s propositions. The weight at one time
attached to his opinions, the sinister influence they exercised over the early
efforts of those who differed from him, and the great and enduring
importance of the points at issue, have made it necessary to refer to them at
length.
The ship had been steadily proceeded with, notwithstanding the adverse
criticism of philosophers, and she was launched on July 19, 1837. On
August 18 she left with a tug-boat for London to take her engines on board,
and arrived in the Thames after a passage of four days, four-fifths of the
way under sail.
When anchored in the river she was crowded with visitors, who,
according to the newspapers of the day, were astonished at ‘her magnificent
proportions and stupendous machinery.’
The engines were at length completed, and received in every detail Mr.
Brunel’s constant supervision.
Extraordinary efforts were made to get the ship back to Bristol and to
start her on her voyage across the Atlantic before the departure of the
‘Sirius’—a vessel of about 700 tons and 320 horse-power, bought by the St.
George’s Steam Packet Company in order to anticipate the ‘Great Western.’

At length the ‘Great Western’ left Blackwall for Bristol, at 6.10 A.M. on
Saturday, March 31, 1838, having on board Captain Claxton, Mr. Guppy,
Mr. Brunel, and many other persons interested in her success. All went well
at first, but at about half-past eight o’clock a very alarming fire broke out.
The felt which covered the boilers had been carried up too high, and the red
lead which fastened it became hot; oil gas was generated, and it burst into a
fearful flame, setting fire to the beams and under part of the deck. The ship
was immediately run ashore on a mud-bank not far from the Chapman
Beacon, while Captain Claxton, Captain Hosken (the commander), and Mr.
Pearne (the chief engineer) endeavoured to extinguish the fire.
Captain Claxton went below through the engine-rooms, and forward
between the boilers to the fore-hatch, and in a stifling atmosphere of
burning paint and felt he directed the nozzle of the fire-hose against the
flames. While he was at work, something heavy fell on him from above. On
recovering from the blow, he stooped down, and found the body of a man,
who was lying insensible, with his head covered to the ears with the water
which had collected on the floor. Captain Claxton called for a rope, and the
almost lifeless body was hauled up. It was not till he went on deck some
time afterwards that he learnt that the person who had fallen on him was
Mr. Brunel, and that he had saved the life of his friend.
It appeared that Mr. Brunel was going down to Captain Claxton’s
assistance by the long ladder which reached from the fore-hatch to the
keelson, and put his foot on a burnt rung. He fell about 18 feet, striking an
iron bar in his descent. Had he not fallen on Captain Claxton he must have
struck the keelson or floor and been killed, and had not his head been raised
at once he would have been suffocated by the water into which he fell. He
was so severely hurt that he could not move, and he was laid on a sail on
deck until the fire was extinguished, and then lowered into a boat, and
landed on Canvy Island, where he remained some weeks. Although his
sufferings were very great, he was able, within three days of the accident, to
dictate a long letter to Captain Claxton on the state of the ship and engines.
The fire was soon got under, the ship resumed her voyage to Bristol, and
anchored at Kingroad in the afternoon of Monday, April 2, to the great
surprise of the good people of Bristol, who had heard that she had been
burnt in the Thames. Their astonishment was increased by finding no
outward signs of the disaster; but, as a fact, the deck above the boiler was

charred a fourth of its thickness, and so remained till the ship was broken
up.
The ‘Great Western’ started on her first voyage to New York on Sunday,
April 8, at 10 A.M.,[124] and struck soundings off Newfoundland on the ninth
day. She arrived at New York at 2 P.M. on Monday, the 23rd, having
consumed three-fourths of the coal she had taken on board.
She found that the ‘Sirius’ had arrived before her; but under all the
circumstances the palm was due to the ‘Great Western,’ for the ‘Sirius’ had
left Cork eight hours before the ‘Great Western’ left Bristol (which lies a
whole day’s run further from New York), and had only arrived at New York
in the morning of the day in the afternoon of which the ‘Great Western’
came in; and, what is after all the most important point for comparison, the
‘Great Western’ had nearly 200 tons of coal left, while the ‘Sirius,’ when
she dropped her anchor at Sandy Hook, had not only consumed all her coal,
but also all the combustible articles which could possibly be thrown on the
fire, including (to repeat the well-known anecdote) a child’s doll!
The ‘Great Western’ was received at New York with well-deserved
honour. According to the journal of one of her passengers, ‘Myriads were
collected, boats had gathered round us in countless confusion, flags were
flying, guns were firing, and cheering rose from the shore, the boats, and all
around loudly and gloriously, as though it would never have done. It was an
exciting moment, a moment of triumph.’
The ship started on her return home on May 7, 1838, with sixty-eight
passengers on board. She made the voyage in fourteen days, although
twenty-four hours were lost by a stoppage at sea.
After this she ran regularly between Bristol and New York till the end of
1846. In April 1847 she was sold to the West India Mail Steam Packet
Company, and became one of their best vessels.

At length in 1857 she was broken up by Messrs. Castle, of Vauxhall.
Among those who went there to take a farewell of her before she finally
disappeared was Mr. Brunel; thus he saw the last of his famous ship.

NOTE (p. 235).

Dimensions of the ‘Great Western’ Steam-Ship.
Feet Inch
Length from fore-part of figurehead to after-part of
236 0
taffrail
Length between the perpendiculars 212 0
Length of keel 205 0
Breadth 35 4
Breadth over paddle-boxes 59 8
Depth of hold 23 2
Draught of water 16 8
Length of engine-room 72 0
Tonnage by measurement 1,340 tons
Displacement at load draught 2,300 "

Dimensions of Engines, &c.
Diameter of cylinders 73½ inches
Length of stroke 7 feet
Weight of engines, wheels, &c. 310 tons
Weight of boilers 90 "
Water 20 tons to each boiler 80 "
9
Diameter of wheel 28 feet
inches
Width of floats 10 feet

CHAPTER IX.

STEAM NAVIGATION. THE ‘GREAT BRITAIN’ STEAM-SHIP.

A.D. 1838—1847. ÆTATIS 33—42.

COMMENCEMENT OF THE BUILDING OF THE ‘GREAT BRITAIN’—REPORT ON THE
ENGINES (JUNE 13, 1839)—EXPERIMENTS ON THE SCREW PROPELLER—ITS ADOPTION
IN THE ‘GREAT BRITAIN’—COMPLETION OF THE SHIP—HER VOYAGE ACROSS THE
ATLANTIC—STRANDING OF THE ‘GREAT BRITAIN’ IN DUNDRUM BAY—LETTER TO
CAPTAIN CLAXTON ON THE CONDITION OF THE ‘GREAT BRITAIN,’ AND ON THE
MEANS TO BE ADOPTED FOR SAVING HER (DECEMBER 10, 1846)—REPORT TO THE
DIRECTORS ON THE SAME SUBJECT (DECEMBER 14, 1846)—APPOINTMENT OF
CAPTAIN CLAXTON TO SUPERINTEND THE EXECUTION OF MR. BRUNEL’S PLANS—
LETTER TO CAPTAIN CLAXTON ON THE DIFFICULTIES TO BE OVERCOME (DECEMBER
29, 1846)—REPORT ENCLOSING CAPTAIN CLAXTON’S ACCOUNT OF THE ERECTION OF
THE BREAKWATER (FEBRUARY 27, 1847)—REPORT ON THE ARRANGEMENTS FOR
FLOATING OFF THE SHIP (MAY 4, 1847)—SUCCESSFUL ACCOMPLISHMENT OF THE
FLOATING OPERATIONS—SUBSEQUENT HISTORY OF THE ‘GREAT BRITAIN’—NOTE:
DIMENSIONS OF THE SHIP AND ENGINES.

THE Directors of the Great Western Steam-Ship Company, encouraged by
the success of the ‘Great Western,’ determined shortly after her first return
to England to lay down a second ship of not less than 2,000 tons burden. As
they did not at that time contemplate the use of iron, a portion of the timber
was purchased, and drawings were put in hand for a wooden ship. The
proposed vessel was intended to be in all respects a companion ship to the
‘Great Western;’ only she was to be of larger dimensions, as it was found
that additional cargo space would be remunerative.
In October 1838, Mr. Guppy (one of the Directors) communicated to the
Board the results of some calculations Mr. Brunel had made relative to the
cost and efficiency of iron vessels as compared with wooden ones. Mr.
Brunel then suggested that Captain Claxton and Mr. Patterson, accompanied
by one of his assistants, should make a voyage to Antwerp and back in the
‘Rainbow,’ an iron steam-boat of 407 tons burden, and report on the subject.
On receiving their report, which was revised by Mr. Brunel, and which was
strongly in favour of the adoption of iron, the Directors resolved to build
their ship of that material, and of not less than 2,000 tons measurement, the

same size as that which they had intended for their wooden ship. They also
determined to erect the shops, and provide the tools for building her
themselves.
As in the case of the ‘Great Western,’ the details of construction were
settled by the Building Committee—Captain Claxton, Mr. Guppy, and Mr.
Brunel—who were assisted by Mr. Patterson.
The preparation of the design occupied some time. In each succeeding
drawing an increased size was proposed; at length the fifth design, showing
a ship of 3,443 tons burden, was finally approved of. On July 19, 1839, the
flat keel plates were laid, and the construction of the hull was commenced.
It will be necessary to enter with some detail into the history of the
construction of the engines of the ‘Great Britain,’ as it has often been stated
that it was on Mr. Brunel’s recommendation that the Company built their
own engines. It appears, however, that Mr. Brunel repeatedly urged upon
the Directors the utmost caution and economy, and that they ultimately
acted ‘against his suggestion.’
When the Directors determined, in May 1838, to build a second ship,
they did not entertain any idea of undertaking so great a responsibility as
the manufacture of the engines; nor had they any intention of doing so, even
when, towards the end of the same year, they resolved to build the ship
themselves, and to construct her of iron.
The dimensions of the proposed paddle engines (for at this date the use
of the screw propeller was not contemplated) were sent, in November 1838,
to Messrs. Maudslay and Field, Messrs. Hall, and Messrs. Seaward.[125]
Messrs. Maudslay declined to tender, and the negotiations seem to have
fallen through at the time; but they were renewed in April 1839, when
estimates for engines (with cylinders of 100 inches diameter and seven feet
stroke) were again invited from several makers.
The contest lay eventually between Messrs. Maudslay and Mr.
Humphrys (whose patent for trunk engines was worked by Messrs. Hall). At
Mr. Brunel’s desire they prepared designs for engines with cylinders of 120
inches diameter. He twice induced the Directors to postpone coming to a
decision on the subject, in order that Messrs. Maudslay might mature their
new patent for double-cylinder engines.
When their tender was placed before the Board, the Directors were of
opinion that it largely exceeded the estimate of Mr. Humphrys. Mr.

Humphrys’ estimate, however, had been more than once sent back to him
for revision, at the suggestion of Mr. Brunel, who expressed doubts as to the
possibility of Mr. Humphrys being able to construct his engines within the
sum named by him.
Messrs. Hall stated that if they tendered for the supply of engines on Mr.
Humphrys’ plan, large tools would have to be purchased by them, and the
cost charged on the one pair of engines; they therefore strongly
recommended the Company to become their own engine makers.
Influenced by these considerations, the Directors determined to adopt the
plan of Mr. Humphrys, and to construct their own engines; and they
appointed him the superintending engineer of their works.
It appears from a report by the secretary, Captain Claxton, dated March
23, 1840, that ‘previous to coming to this decision, Mr. Brunel succinctly
laid before the Directors his views of the matter, and his opinion of the great
responsibility they would incur if they made their own engines; and
doubtless the Directors would have yielded to his suggestions, but for the
report of Mr. Humphrys, showing the utter hopelessness of getting the
engines made piecemeal in Bristol.’
The following is the report of Mr. Brunel on the subject:—

June 12, 1839.
At the request of Mr. Maze and Mr. Scott, whom I had the pleasure of meeting on Saturday last, I
send you the following observations on the two plans and the estimates of Messrs. Maudslay, and of
our Mr. Humphrys.
I have a copy of Messrs. Maudslay’s letter of the 29th ult. containing their tender, and a
subsequent letter of the 11th inst. in reply to some enquiries of mine respecting their tender and Mr.
Humphrys’ estimates, according to which the total cost of a pair of engines of 110 inches diameter
and 8 feet stroke, upon his plan, and I presume modified as last recommended by Mr. Guppy and
myself, including boilers and fixing on board, would be 29,296l., or, as stated by Captain Claxton in
a letter to me of the 1st inst., 30,700l.
First, as to the comparative merits of the plans, I consider them both excellently adapted to our
particular case, and that the choice will depend upon other circumstances than the construction of the
engines, and these circumstances, I consider, would be, the relative cost and the advantages of
forming an establishment which will eventually become necessary for the repair and maintenance of
our engines, contrasted with all the advantages to be derived from the responsibility and experience
in all the details of a first-rate manufacturer, and to which I attach very great value, particularly in the
early proceedings of a Company like ours. As regards the cost, I understand Messrs. Maudslay’s
tender to be for an engine of four 75-inch cylinders, which is equal to a pair of ordinary engines of
about 106 inches.

Engine, boiler, and paddle-wheels, fixed on board, supposing the £
vessel in London, and with reduced size of boiler, 41,400
Deduct allowance for coal-boxes and combings for hatchways as
proposed
by Messrs. Maudslay, 500
40,900
Additional expense incurred by Messrs. Maudslay in consequence
of
the engines being fixed on board at Bristol instead of London, I
estimate at, 250
Total amount to be paid Messrs. Maudslay, 41,150
In addition to this will be the freight and insurance, which we are to
pay, and also the unloading at Bristol and placing in the vessel,
which I take at Captain Claxton’s estimate, 2,000
Making a total of 43,150

It is to be observed that this includes Mr. Field’s apparatus for changing water, Kingston’s cocks,
casing the cylinders, and all those extras which were applied to the ‘Great Western,’ and also the
paddle-beams and paddle-wheels. Without these latter the nett cost of the engine, fixed in place, and
including all other extras, would appear to be about 40,000l. or 40,500l. If the cylinders be increased
to 77¾, which would be equivalent to the pair of 110 inch, and supposing the cost of the engines to

increase in the same ratio as the power resulting from this increase, but which ought not to be the
case, the total cost, according to Messrs. Maudslay’s estimate, will be 46,500l., and deducting the
paddle-beams or framework for carrying the paddles, which do not, I think, form part of Mr.
Humphrys’ estimate, probably about 45,500l. as compared with Mr. Humphrys’ estimate of 30,700l.
With respect to this latter estimate, I cannot help expressing the fears I entertain that Mr. Humphrys is
over-sanguine, and that the cost would greatly exceed the sum named. The items seem to me to be
moderate prices only for each article named, and I see no allowance for those alterations, damages,
and waste of parts, and a variety of other contingencies, which in a piece of machinery of this
magnitude and novelty is certain to amount to a very large sum.
In his estimate of the fittings and smaller parts, I think also he has greatly underrated them.
The outlay for tools and tackle would, I think, also be greater than he seems to anticipate, and on
the whole I cannot but come to the conclusion in my own mind, and I should not act rightly if I did
not communicate that opinion to you, that the first outlay will be fully as large and probably larger by
adopting the plan of making our own engines than by employing a manufacturer. It is true we shall
have some valuable and costly tools and shops included in this outlay, and a fine establishment
formed, which may be rendered fully competent in point of means to continue the manufacture of
engines for others, and to keep up the repairs of any number of engines which the Company are
likely to have at work. My only fear would be that of the risk of the undertaking being too great for a
newly-formed establishment. The making of the vessel itself is no mean effort, and to superadd the
construction of the largest pair of engines and boilers yet made, and upon a new plan, is calculating
very much upon every effort being successful, and particularly upon the continued assistance of those
who have hitherto attended to the subject; as it must be well known to the Directors that if Mr.
Guppy, for instance, should be prevented from giving his time as he has hitherto done, or if Mr.
Humphrys should, from illness or other causes, leave us, the manufactory would be brought to a
stand, and the loss would be serious. I have no wish to deter the Company from becoming their own
manufacturers—I think it a course which must ultimately be adopted if the Company thrive—but I
should have much preferred that it had been adopted gradually, that we had commenced with a
vessel, and then proceeded with boilers and repairs; and, as our establishment became formed and
matured, and when we might no longer depend entirely upon the engineering talents and assistance of
one Director, who may be unable to attend to it, or upon the health of one superintendent who, as yet,
is alone in possession of all our plans and ideas, and at present is alone capable of carrying them out,
we might then have ventured upon making the engines perhaps for the third vessel. Circumstances
may, however, render it necessary that we should proceed more expeditiously, and I am only anxious
that the Directors should be aware of the difficulties that we may have to encounter, and that they
should not form expectations as regards economy in which they may be disappointed. The result of
the best consideration I have been able to give to it is, that the question does not seem to be one of
cost. In that respect, according to my view, the two modes of proceeding would be nearly balanced,
but it resolves itself into the following question:—Is it better in our present position to enter at once
upon the manufacture of the engines and boilers, in doing which we shall in part repay the cost of
tools and shops, which must eventually be required, and by which we shall be more independent, and
more capable of expediting the works, should it become desirable to incur any additional expense for
that purpose, or to throw all the responsibility and risk on another party or contractor—the vessel, for
which we could not easily contract, being still made in the Company’s yard?
I have thus reduced the question to that state in which I can offer no further opinion or advice; it
is now for you to determine. The question is one which has frequently to be decided upon by the
Directors of public works; it is very much a matter of feeling, but it is simplified in the present
instance by the circumstance that the expense in either case will be, to my view at least, about the
same, and the work, I have no doubt, equally good in either case.
Upon this point, as perhaps upon the subject of cost, I have no doubt there will be some
difference of opinion. It will be said that the work done under our own superintendence can be more

relied upon than the work of a manufacturer, and that even in the engines of the ‘Great Western’
steam-ship, coming from one of the most experienced manufacturers, many defects may be pointed
out.
I should agree fully with both these arguments, but I think these advantages are fully
counterbalanced by that of the experience in all the details which is brought into operation in an old-
established manufactory, and the great relief from responsibility and risk obtained by contracting for
the whole work.

The Directors having determined to make the engines, erected shops and
fitted them up with proper tools. The services rendered to them by Mr.
Brunel at this period were fully acknowledged at the next meeting of the
shareholders.[126]
Mr. Brunel’s attention was now anxiously devoted to the consideration
of the numerous questions involved in the construction of the ship and her
engines; and, in order to obtain reliable information on many points, he sent
one of his assistants, Mr. Berkeley Claxton, in the ‘Great Western.’ His sole
occupation during six voyages was to note the amount of rolling and
pitching, and the exact performance of her engines, with the effect of the
use of the expansion valves on her speed, and on the consumption of fuel.
These reports furnished Mr. Brunel with information which was of great
value, especially when, shortly afterwards, he advised the Directors to adopt
the screw propeller instead of paddlewheels.
The circumstances which led to the adoption of the screw propeller in
the ‘Great Britain’ instead of paddlewheels were as follows:—
In the early part of the year 1840, the performances of the ‘Archimedes’
steamer began to attract the attention of scientific men. This vessel, which
was fitted with the screw propeller patented by Mr. Francis Pettitt Smith,
arrived at Bristol in May. A few trips were made up and down the Float, but
the advantages of the screw propeller were not fully appreciated by those to
whom they were explained.
But Mr. Guppy, who had attended some of these trials, went round in the
ship to Liverpool. On his return he made a report to the Building
Committee, and the Directors, on Mr. Brunel’s advice, passed a resolution
delaying the progress of the engines of the ‘Great Britain,’ and of those
parts of the frame which would be affected by any change of plans. Mr.
Brunel was also requested by them to give his attention to the question of
the adoption of the screw, and to report thereon.

During the next three months experiments were made by Mr. Brunel,
assisted by Mr. Guppy and Captain Claxton, on the screw propeller in the
‘Archimedes.’[127] These experiments afforded ample opportunity of trying
the performances of several forms of screws.[128]
On October 1, Mr. Brunel attended a special meeting of the Board, and
read and explained a report he had drawn up, in which he laid before the
Directors at great length the results of the different experiments he had
made, and the advantages which he believed would attend the use of the
screw propeller.[129] A resolution was passed adopting it for the ‘Great
Britain.’
Mr. Brunel at first thought that he would be able to retain the form of
engines which had been originally determined on for working the paddle
wheels; but, on consideration, this was found impracticable. As the
Company had by this time erected complete engine works, there could now
be no question as to their undertaking the construction of the new
description of engines required for working the screw propeller.[130]
Mr. Humphrys resigned the post of superintendent of the works, and Mr.
Harman was appointed assistant engineer under Mr. Guppy, to whom the
Directors, on the advice of Mr. Brunel, entrusted the supreme control of
their manufacturing establishment.
The duties and responsibilities which devolved on the Building
Committee—Captain Claxton, Mr. Guppy, and Mr. Brunel—were most
arduous. To design and construct a steam-ship larger than any that had, up
to that time, been launched, to make this ship of a material which had but
lately been introduced into shipbuilding, and which had never before been
employed on a large scale, to adapt to this ship a novel form of propeller
which had not previously been used save in a merely experimental steamer,
and to build in a newly opened manufactory marine engines of a much
greater size than any that had hitherto been contemplated, and of a totally
different character, was indeed a bold enterprise. Mr. Brunel had, as has
been shown, recommended the Company not to undertake one part of the
work, that, namely, of the manufacture of the engines, which he thought
would have been better entrusted to the most experienced engine builders.
But although the Directors had acted contrary to his advice, this
circumstance in no way diminished the zeal with which he and his
coadjutors entered upon their task.

A short statement of the principal dimensions of the vessel and engines
is given in a note to this chapter; but some of the more remarkable features
in the design may be mentioned here.
In the construction of the ‘Great Britain,’ the same care which had been
spent in securing longitudinal strength in the wooden hull of the ‘Great
Western,’ was now given to the suitable distribution of the metal. Over the
transverse angle iron ribs at the bottom of the ship were laid ten deep
longitudinal beams (see woodcut, fig. 13, a), which, over the greater part of
the bottom of the ship, were covered with an iron deck (b) riveted to their
upper edges by angle irons, thus forming a cellular structure which added
greatly to the strength of the ship. It does not appear that this deck was
designed to be watertight, so that it did not form the same security against
accident as the inner skin of the cellular structure which Mr. Brunel
afterwards adopted in the ‘Great Eastern.’
The upper part of the sides of the ship, in the middle of her length, were
carefully designed so as to give her longitudinal strength. The side plates
were thickened, and were riveted to iron shelf-plates three feet broad (c);
and two bands of iron, six inches wide and one inch thick, with the joints
strengthened, ran along the top of the ship’s side. There were bands of iron
riveted to the shelf-plate, and iron deck beams crossed diagonally under the
planking of the upper and main decks. Also at the junction of the ship’s side
with the shelf-plate there ran longitudinally a tie of Baltic pine timber, 340
square inches in section (d); this being well secured to the shelf-plate and
ribs, added considerably to the strength of this portion of the hull.
The ship had five watertight bulkheads, and was thus separated into six
compartments.

Fig. 13. ‘Great Britain’ Steam-Ship.

Transverse Section.

She had no keel, as there did not appear to be sufficient advantage
gained by such an appendage to make up for the increase of the ship’s
draught by the amount of the depth of the keel. There were two side or bilge
keels (e), reaching down to the level of the keel plate of the ship, so that
when grounded in dock she might rest on three points in her width.
The ‘Great Britain’ had what is termed a balanced rudder, a portion of
the rudder (in this case about one third) being in advance of the pivot on
which it turned. The result of this arrangement was that, the pressures on
either side of the pivot nearly balancing one another, there was no difficulty
in putting the helm over rapidly. This rudder was knocked away when the
ship ran ashore at Dundrum, and was subsequently replaced by an ordinary
rudder.[131]
In the construction of the hull of the ship, instead of a mere imitation of
the arrangements of the timber in wooden ships, the proper distribution of
the material to receive the strains that would come upon it was carefully
considered. In the result, the ship contained, in the structure of her bottom,
bulkheads, deck shelves, and longitudinal kelsons, the longitudinal principle
of construction which Mr. Brunel afterwards so fully developed in the
‘Great Eastern.’
Apart from their size, the design of the engines of the ‘Great Britain’
necessarily presented many peculiarities. The boilers, which were six in
number, were placed touching each other, so as to form one large boiler
about thirty-three feet square, divided by one transverse and two
longitudinal partitions. This boiler, which was fitted in between the
longitudinal bulkheads of the ship, had a double set of furnaces, and
therefore of stoke-holes, one at the fore end, and the other at the after end,
next the engine room.
It would seem that the boiler was only worked with a pressure of about
eight pounds on the square inch.
The feed water for the boiler was passed through a casing surrounding
the funnel, in which it was heated before passing into the boiler. This casing
was open at the top, and the water flowed thence into the boiler by
gravitation. A similar arrangement was adopted by Mr. Brunel in the ‘Great
Eastern.’

The condensers were made of wrought iron, being in fact part of the
frame of the ship. The main shaft of the engine had a crank at either end of
it, and was made hollow, a stream of water being kept running through it so
as to prevent heating in the bearings. An important point in the design was
the method by which the motion was transmitted from the engine-shaft to
the screw-shaft, for the screw was arranged to go three revolutions to each
revolution of the engines. Where the engines do not drive the screw directly,
this is now universally effected by means of toothed gearing; but, when the
engines of the ‘Great Britain’ were made, it was thought that this
arrangement would be too jarring and noisy. After much consideration,
chains were used, working round different-sized drums with notches in
them, into which fitted projections on the chains. The greater part of the
length of the screw-shaft consisted of a hollow wrought-iron boiler-plate
tube, the metal being thus very advantageously placed for taking torsional
strain, and the shaft was in this way made very light. The engines were
designed to work expansively, the steam being cut off at one-sixth of the
stroke.
The completion of the ‘Great Britain’ was delayed many months, owing
to the financial difficulties in which the Great Western Steam-Ship
Company had become involved; the profit on working the ‘Great Western’
having been seriously diminished in consequence of the competition of the
Cunard steamers.
At length, however, the ship was finished; and she was floated out of
dock into the Floating Harbour on July 19, 1843, in the presence of His
Royal Highness Prince Albert.
This seems a fitting place to insert the following letter from Mr. Brunel
to Mr. Guppy, written at the beginning of August 1843:—
I have been thinking a great deal of your plans for iron-ship building, and have come to a
conclusion which I believe agrees with your ideas; but I will state mine without reference to yours. At
bottom and at top I would give longitudinal strength and stiffness, gaining the latter by the former, so
that all the metal used should add to the longitudinal tie, while in the neutral axis and along the sides,
and to resist swells from seas, I would have vertical strength by ribs and shelf-pieces, thus: the black
lines being sections of longitudinal pieces, the dotted lines vertical and transverse diagonal plates,
throwing the metal as much as possible into the outside bottom plates, and getting the strength inside
by form, that is, depth of beams, &c., the former being liable to injury from blows, &c., the latter
being protected.
And now for the screw of which I am constantly thinking, and in the success of which for the
‘Great Britain,’ remember, I am even more deeply interested than you.

If all goes well we shall all gain credit, but ‘quod scriptum
est manet,’ if the result disappoint anybody, my written report [Fig. 14.]
will be remembered by everybody, and I shall have to bear the
storm—and all that spite and revenge can do at the Admiralty
will be done! The words ‘better sailing qualities than could be
given to the “Polyphemus,”’ which I used in my first report to
the Admiralty, I believe have never been forgotten.
Well, the result of all my anxious thoughts—for I assure you
I feel more anxious about this than about most things I have had
to do with—is first that we must adopt as a principle not to be
departed from, that all mechanical difficulties of construction
must give way, must in fact be lost sight of in determining the most perfect form—if we find that the
screw determined upon cannot be made (but what cannot be done?), then it is quite time enough to
try another form; though even then my rule would be to try again at making it....

The ‘Great Britain’ was built wider than the locks through which she
would have to pass, as it was supposed that the Dock Company would
allow them to be temporarily widened.[132]
After a good deal of discussion, negotiations were satisfactorily
concluded, and the requisite alterations were made: the ship passed through
into Cumberland Basin, and the upper lock was restored to its original state
in a few days.
On December 10, everything was ready for her passing into the Avon
through the lower lock. A steam-tug commenced towing her at high water,
but, before she had moved half her length in the lock, it became evident to
Captain Claxton, who was on board the tug, that there was not an inch to
spare; she was touching the lock walls on either side—in fact, she had stuck
between the copings. Upon this he gave orders to haul her back again as
quickly as possible. This was hardly effected before the tide began to fall; a
few minutes later, and the ship would have remained jammed in the
entrance.
As the tides had passed their highest, it was necessary immediately to
widen the lock, in order not to lose the spring tide; and this was
accomplished under Mr. Brunel’s superintendence, just in time to get the
vessel through that night.
Mr. Brunel described this occurrence in the following letter, written to
excuse himself from keeping an important engagement in Wales:—
December 11, 1844.
We have had an unexpected difficulty with the ‘Great Britain’ this morning. She stuck in the
lock; we did get her back. I have been hard at work all day altering the masonry of the lock. To night,
our last tide, we have succeeded in getting her through; but, being dark, we have been obliged to