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Title: Chemical warfare

Author: Amos A. Fries
Clarence J. West

Release date: October 22, 2023 [eBook #71931]

Language: English

Original publication: New York: McGraw Hill, 1921

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CHEMICAL WARFARE

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CHEMICAL WARFARE
BY
AMOS A. FRIES
Brigadier General, C. W. S., U. S. A.
Chief, Chemical Warfare Service

AND
CLARENCE J. WEST
Major, C. W. S. Reserve Corps, U. S. A.
National Research Council

First Edition

McGRAW-HILL BOOK COMPANY, Inc.
NEW YORK: 370 SEVENTH AVENUE
LONDON: 6 & 8 BOUVERIE ST., E. C. 4
1921

Copyright, 1921, by the
McGraw-Hill Book Company, Inc.

PREFACE
Shortly after the signing of the Armistice, it was realized that the story
of Chemical Warfare should be written, partly because of its historical
value, and partly because of the future needs of a textbook covering the
fundamental facts of the Service for the Army, the Reserve Officer, the
National Guard, and even the Civilian Chemist. The present work was
undertaken by both authors as a labor of patriotism and because of their
interest in the Service.
The two years which have elapsed since the initial discussion of the
outlines of the book have thoroughly convinced us of the need of such a
work. The Engineers, the Medical Department, and most of the other
branches of the Army have their recognized textbooks and manuals. There
has been no way, however, by which the uninformed can check the
accuracy of statements regarding Chemical Warfare. The present volume
will serve, in a measure, to fill this gap. That it does not do so more
completely is due in part to the fact that secrecy must still be maintained
about some of the facts and some of the new discoveries which are the
property of the Service. Those familiar with the work of the Chemical
Warfare Service will discover, though, that the following pages contain
many statements which were zealously guarded secrets two years ago. This
enlarged program of publicity on the part of the Chief of the Service is
being justified every day by the ever increasing interest in this branch of
warfare. Where five men were discussing Chemical Warfare two years ago,
fifty men are talking about the work and the possibilities of the Service
today. It is hoped that the facts here presented may further increase the
interest in Chemical Warfare, for there is no question but that it must be
recognized as a permanent and a very vital branch of the Army of every
country. Reasons for this will be found scattered through the pages of this
book.
It should be explained that this is in no sense a complete historical
sketch of the development and personnel of the Chemical Warfare Service.
At least two more volumes are needed,—one on the Manufacture of

Poisonous Gases and one on the Tactics of Chemical Warfare. We have
purposely refrained from an attempt to give credit to individuals for the
accomplishments of the various Divisions of the Service, because such an
attempt would have made the book too voluminous, and would have
defeated the primary purpose, namely, that it should present the information
in as concise manner as possible. The published and unpublished materials
of the files of all the Divisions have been freely drawn upon in writing the
various chapters, and many old C. W. S. men will undoubtedly recognize
whole sentences which they wrote under the stress of the laboratory or plant
“battle front.” May these few lines be an acknowledgment of their
contributions. Those who desire to consult the literature of Chemical
Warfare will find a fairly complete bibliography (to about the middle of
1919) in “Special Libraries” for November, 1919.
Special acknowledgment is made to Dr. G. J. Esselen, Jr., for having
read the manuscript and for helpful and constructive criticisms. Many of the
figures are reproduced by permission of the Journal of Industrial and
Engineering Chemistry; those showing the Nelson cell were furnished by
the Samuel M. Green Company.

Amos A. Fries,
Clarence J. West.
Aug. 1, 1921.

FOREWORD
After all peaceful means of settling disputes between nations have been
resorted to and have failed, war is often declared by one of the disputants
for the purpose of imposing its will upon the other by force. In order to
accomplish this, a superiority must be established over the adversary in
trained men and in implements of war.
Men are nothing in modern war unless they are equipped with the most
effective devices for killing and maiming the enemy’s soldiers and
thoroughly trained in the use of such implements.
History proves that an effective implement of war has never been
discarded until it becomes obsolete.
It is impossible to humanize the act of killing and maiming the enemy’s
soldiers, and there is no logical grounds on which to condemn an appliance
so long as its application can be so confined. Experiments in this and other
countries during the World War completely established the fact that gas can
be so confined. The range of gas clouds is no greater than that of artillery
and the population in the area behind the front line must, if they remain in
such range, take their chance. The danger area in the future will be known
to all.
As the first Director of the Chemical Warfare Service, U. S. Army, I
speak with some experience when I say that there is no field in which the
future possibilities are greater than in chemical warfare, and no field in
which neglect to keep abreast of the times in research and training would be
more disastrous.
Notwithstanding the fact that gas was used in the World War two years
before the United States entered the fray, practically nothing was done in
this country before April, 1917, towards the development of any chemical
warfare appliances, offensive or defensive, and had it not been for the
ability of an ally to supply our troops with such appliances, they would
have been as defenseless as the Canadians were at Ypres when the Germans
sent over their first gas cloud.

This book recites the troubles and successes of this new service under
the stress of war for which it was unprepared and I trust that its perusal will
create a public opinion that will insist upon chemical preparation for war.
I feel that this book will show that the genius and patriotism displayed
by the chemists and chemical engineers of the country were not surpassed
in any other branch of war work and that to fail to utilize in peace times this
talent would be a crime.

William L. Sibert,
Major General, United States Army,
Retired.

CONTENTS

page
Preface vii
Foreword ix
chapter
I. The History of Poison Gases 1
II. Modern Development of Gas Warfare 10
III. Development of the
Chemical Warfare Service 31
IV. The Chemical Warfare Service in France 72
V. Chlorine 116
VI. Phosgene 126
VII. Lachrymators 137
VIII. Chloropicrin 144
IX. Dichloroethylsulfide (Mustard Gas) 150
X. Arsenic Derivatives 180
XI. Carbon Monoxide 190
XII. Development of the Gas Mask 195
XIII. Absorbents 237
XIV. Testing Absorbents and Gas Masks 259
XV. Other Defensive Measures 272
XVI. Screening Smokes 285
XVII. Toxic Smokes 313
XVIII. Smoke Filters 322
XIX. Signal Smokes 330
XX. Incendiary Materials 336
XXI. The Pharmacology of War Gases 353
XXII. Chemical Warfare in Relation to
Strategy and Tactics 363
XXIII. The Offensive Use of Gas 385

XXIV. Defense against Gas 405
XXV. Peace Time Uses of Gas 427
XXVI. The Future of Chemical Warfare 435
Index 440

CHEMICAL WARFARE

CHAPTER I
THE HISTORY OF POISON GASES [1]
The introduction of poison gases by the Germans at Ypres in April,
1915, marked a new era in modern warfare. The popular opinion is that this
form of warfare was original with the Germans. Such, however, is not the
case. Quoting from an article in the Candid Quarterly Review, 4, 561, “All
they can claim is the inhuman adoption of devices invented in England, and
by England rejected as too horrible to be entertained even for use against an
enemy.” But the use of poison gases is even of an earlier origin than this
article claims.
The first recorded effort to overcome an enemy by the generation of
poisonous and suffocating gases seems to have been in the wars of the
Athenians and Spartans (431-404 b.c.) when, besieging the cities of Platea
and Belium, the Spartans saturated wood with pitch and sulfur and burned it
under the walls of these cities in the hope of choking the defenders and
rendering the assault less difficult. Similar uses of poisonous gases are
recorded during the Middle Ages. In effect they were like our modern stink
balls, but were projected by squirts or in bottles after the manner of a hand
grenade. The legend is told of Prester John (about the eleventh century),
that he stuffed copper figures with explosives and combustible materials
which, emitted from the mouths and nostrils of the effigies, played great
havoc.
The idea referred to by the writer in the Candid Quarterly Review, is
from the pen of the English Lord Dundonald, which appeared in the
publication entitled “The Panmure Papers.” This is an extremely dull record
of an extremely dull person, only rendered interesting by the one portion,
concerned with the use of poison gases, which, it is said, “should never
have been published at all.”
That portion of the article from the Candid Quarterly Review dealing
with the introduction of poisonous gas by the Germans, and referred to in
the first paragraph above, is quoted in full as follows:

“The great Admiral Lord Dundonald—perhaps the
ablest sea captain ever known, not even excluding Lord
Nelson—was also a man of wide observation, and no
mean chemist. He had been struck in 1811 by the deadly
character of the fumes of sulphur in Sicily; and, when the
Crimean War was being waged, he communicated to the
English government, then presided over by Lord
Palmerston, a plan for the reduction of Sebastopol by
sulphur fumes. The plan was imparted to Lord Panmure
and Lord Palmerston, and the way in which it was
received is so illustrative of the trickery and treachery of
the politician that it is worth while to quote Lord
Palmerston’s private communication upon it to Lord
Panmure:

“Lord Palmerston to Lord Panmure
“‘House of Commons, 7th August, 1855 “‘I agree with
you that if Dundonald will go out himself to superintend
and direct the execution of his scheme, we ought to
accept his offer and try his plan. If it succeeds, it will, as
you say, save a great number of English and French lives;
if it fails in his hands, we shall be exempt from blame,
and if we come in for a small share of the ridicule, we
can bear it, and the greater part will fall on him. You had
best, therefore, make arrangement with him without
delay, and with as much secrecy as the nature of things
will admit of.’

“Inasmuch as Lord Dundonald’s plans have already
been deliberately published by the two persons above
named, there can be no harm in now republishing them.
They will be found in the first volume of ‘The Panmure
Papers’ (pp. 340-342) and are as follows:

“‘(Enclosure)
“‘Brief Preliminary Observations

“‘It was observed when viewing the Sulphur Kilns, in
July, 1811, that the fumes which escaped in the rude
process of extracting the material, though first elevated
by heat, soon fell to the ground, destroying all vegetation,
and endangering animal life to a great distance, and it
was asserted that an ordinance existed prohibiting
persons from sleeping within the distance of three miles
during the melting season.
“‘An application of these facts was immediately made
to Military and Naval purposes, and after mature
consideration, a Memorial was presented on the subject
to His Royal Highness the Prince Regent on the 12th of
April, 1812, who was graciously pleased to lay it before a
Commission, consisting of Lord Keith, Lord Exmouth
and General and Colonel Congreve (afterwards Sir
William), by whom a favorable report having been given,
His Royal Highness was pleased to order that secrecy
should be maintained by all parties.

“‘(Signed) Dundonald
“‘7th August, 1855’

“‘Memorandum
“‘Materials required for the expulsion of the Russians
from Sebastopol: Experimental trials have shown that
about five parts of coke effectually vaporize one part of
sulphur. Mixtures for land service, where weight is of
importance, may, however, probably be suggested by
Professor Faraday, as to operations on shore I have paid
little attention. Four or five hundred tons of sulphur and
two thousand tons of coke would be sufficient.
“‘Besides these materials, it would be necessary to
have, say, as much bituminous coal, and a couple of
thousand barrels of gas or other tar, for the purpose of

masking fortifications to be attacked, or others that flank
the assailing positions.
“‘A quantity of dry firewood, chips, shavings, straw,
hay or other such combustible materials, would also be
requisite quickly to kindle the fires, which ought to be
kept in readiness for the first favourable and steady
breeze.

“‘Dundonald
“‘7th August, 1855’

“‘Note.—The objects to be accomplished being
specially stated the responsibility of their
accomplishment ought to rest on those who direct their
execution.
“‘Suppose that the Malakoff and Redan are the
objects to be assailed it might be judicious merely to
obscure the Redan (by the smoke of coal and tar kindled
in ‘The Quarries’), so that it could not annoy the
Mamelon, where the sulphur fire would be placed to
expel the garrison from the Malakoff, which ought to
have all the cannon that can be turned towards its
ramparts employed in overthrowing its undefended
ramparts.
“‘There is no doubt but that the fumes will envelop
all the defenses from the Malakoff to the Barracks, and
even to the line of battleship, the Twelve Apostles, at
anchor in the harbour.
“‘The two outer batteries, on each side of the Port,
ought to be smoked, sulphured, and blown down by
explosion vessels, and their destruction completed by a
few ships of war anchored under cover of the smoke.’
“That was Lord Dundonald’s plan in 1855,
improperly published in 1908, and by the Germans, who

thus learnt it, ruthlessly put into practise in 1915.
“Lord Dundonald’s memoranda, together with further
elucidatory notes, were submitted by the English
government of that day to a committee and subsequently
to another committee in which Lord Playfair took leading
part. These committees, with Lord Dundonald’s plans
fully and in detail before them, both reported that the
plans were perfectly feasible; that the effects expected
from them would undoubtedly be produced; but that
those effects were so horrible that no honorable
combatant could use the means required to produce them.
The committee therefore recommended that the scheme
should not be adopted; that Lord Dundonald’s account of
it should be destroyed. How the records were obtained
and preserved by those who so improperly published
them in 1908 we do not know. Presumably they were
found among Lord Panmure’s papers. Admiral Lord
Dundonald himself was certainly no party to their
publication.”
One of the early, if not the earliest suggestion as to the use of poison gas
in shell is found in an article on “Greek Fire,” by B. W. Richardson.[2] He
says:

“I feel it a duty to state openly and boldly, that if
science were to be allowed her full swing, if society
would really allow that ‘all is fair in war,’ war might be
banished at once from the earth as a game which neither
subject nor king dare play at. Globes that could distribute
liquid fire could distribute also lethal agents, within the
breath of which no man, however puissant, could stand
and live. From the summit of Primrose Hill, a few
hundred engineers, properly prepared, could render
Regent’s Park, in an incredibly short space of time,
utterly uninhabitable; or could make an army of men, that

should even fill that space, fall with their arms in their
hands, prostrate and helpless as the host of Sennacherib.
“The question is, shall these things be? I do not see
that humanity should revolt, for would it not be better to
destroy a host in Regent’s Park by making the men fall as
in a mystical sleep, than to let down on them another host
to break their bones, tear their limbs asunder and gouge
out their entrails with three-cornered pikes; leaving a vast
majority undead, and writhing for hours in torments of
the damned? I conceive, for one, that science would be
blessed in spreading her wings on the blast, and breathing
into the face of a desperate horde of men prolonged sleep
—for it need not necessarily be a death—which they
could not grapple with, and which would yield them up
with their implements of murder to an enemy that in the
immensity of its power could afford to be merciful as
Heaven.
“The question is, shall these things be? I think they
must be. By what compact can they be stopped? It were
improbable that any congress of nations could agree on
any code regulating means of destruction; but if it did, it
were useless; for science becomes more powerful as she
concentrates her forces in the hands of units, so that a
nation could only act, by the absolute and individual
assent of each of her representatives. Assume, then, that
France shall lay war to England, and by superior force of
men should place immense hosts, well armed, on English
soil. Is it probable that the units would rest in peace and
allow sheer brute force to win its way to empire? Or put
English troops on French soil, and reverse the question?
“To conclude. War has, at this moment, reached, in its
details, such an extravagance of horror and cruelty, that it
can not be made worse by any art, and can only be made
more merciful by being rendered more terribly energetic.
Who that had to die from a blow would not rather place

his head under Nasmyth’s hammer, than submit it to a
drummer-boy armed with a ferrule?”

The Army and Navy Register of May 29, 1915, reports that

“among the recommendations forwarded to the Board of
Ordnance and Fortifications there may be found many
suggestions in favor of the asphyxiation process, mostly
by the employment of gases contained in bombs to be
thrown within the lines of the foe, with varying effects
from peaceful slumber to instant death. One ingenious
person suggested a bomb laden to its full capacity with
snuff, which should be so evenly and thoroughly
distributed that the enemy would be convulsed with
sneezing, and in this period of paroxysm it would be
possible to creep up on him and capture him in the throes
of the convulsion.”
That the probable use of poisonous gas has often been in the minds of
military men during recent times is evidenced by the fact that at the Hague
Conference in 1899 several of the more prominent nations of Europe and
Asia pledged themselves not to use projectiles whose only object was to
give out suffocating or poisonous gases. Many of the Powers did not sign
this declaration until later. Germany signed and ratified it on Sept. 4, 1900,
but the United States never signed it. Further, this declaration was not to be
binding in case of a war in which a non-signatory was or became a
belligerent. Admiral Mahan, a United States delegate, stated his position in
regard to the use of gas in shell (at that time an untried theory) as follows:
“The reproach of cruelty and perfidy addressed
against these supposed shells was equally uttered
previously against fire-arms and torpedoes, although both
are now employed without scruple. It is illogical and not
demonstrably humane to be tender about asphyxiating
men with gas, when all are prepared to admit that it is
allowable to blow the bottom out of an ironclad at
midnight, throwing four or five hundred men into the sea

to be choked by the water, with scarcely the remotest
chance to escape.”
At the Hague Congress of 1907, article 23 of the rules adopted for war
on land states:
“It is expressly forbidden (a), to employ poisons or
poisonous weapons.”
Before the War suffocating cartridges were shot from the cartridge-
throwing rifle of 26 mm. These cartridges were charged with ethyl
bromoacetate, a slightly suffocating and non-toxic lachrymator. They were
intended for attack on the flanking works of permanent fortifications,
flanking casements or caponiers, into which the enemy tried to make the
cartridges penetrate through the narrow slits used for loopholes. The men
who were serving the machine guns or the cannon of the flanking works
would have been bothered by the vapor from the ethyl bromoacetate, and
the assailant would have profited by their disturbance to get past the
obstacle presented by the fortification. The employment of these devices,
not entailing death, did not contravene the Hague conventions.
The only memorable operations in the course of which these devices
were used before the War was the attack on the Bonnet gang at Choisy-le-
roi.
In connection with the suggested use of sulfur dioxide by Lord
Dundonald and the proposed use of poisonous gases in shell, the following
description of a charcoal respirator by Dr. J. Stenhouse,[3] communicated by
Dr. George Wilson in 1854, is of interest.
“Dr. Wilson commenced by stating that, having read
with much interest the account of Dr. Stenhouse’s
researches on the deodorizing and disinfecting properties
of charcoal, and the application of these to the
construction of a new and important kind of respirator, he
had requested the accomplished chemist to send one of
his instruments for exhibition to the society, which he had
kindly done. Two of the instruments were now on the
table, differing, however, so slightly in construction, that
it would be sufficient to explain the arrangement of one

of them. Externally, it had the appearance of a small
fencing-mask of wire gauze, covering the face from the
chin upwards to the bridge of the nose, but leaving the
eyes and forehead free. It consisted, essentially, of two
plates of wire gauze, separated from each other by a
space of about one-fourth or one-eighth of an inch, so as
to form a small cage filled with small fragments of
charcoal. The frame of the cage was of copper, but the
edges were made of soft lead, and were lined with velvet,
so as to admit of their being made to fit the cheeks tightly
and inclose the mouth and nostrils. By this arrangement,
no air could enter the lungs without passing through the
wire gauze and traversing the charcoal. An aperture is
provided with a screw or sliding valve for the removal
and replenishment of the contents of the cage, which
consist of the siftings or riddlings of the lighter kinds of
wood charcoal. The apparatus is attached to the face by
an elastic band passing over the crown of the head and
strings tying behind, as in the case of the ordinary
respirator. The important agent in this instrument is the
charcoal, which has so remarkable a power of absorbing
and destroying irritating and otherwise irrespirable and
poisonous gases or vapors that, armed with the respirator,
spirits of hartshorn, sulphuretted hydrogen,
hydrosulphuret of ammonia and chlorine may be breathed
through it with impunity, though but slightly diluted with
air. This result, first obtained by Dr. Stenhouse, has been
verified by those who have repeated the trial, among
others by Dr. Wilson, who has tried the vapors named
above on himself and four of his pupils, who have
breathed them with impunity. The explanation of this
remarkable property of charcoal is two-fold. It has long
been known to possess the power of condensing into its
pores gases and vapors, so that if freshly prepared and
exposed to these, it absorbs and retains them. But it has
scarcely been suspected till recently, when Dr. Stenhouse
pointed out the fact, that if charcoal be allowed to absorb

simultaneously such gases as sulphuretted hydrogen and
air, the oxygen of this absorbed and condensed air rapidly
oxidizes and destroys the accompanying gas. So marked
is this action, that if dead animals be imbedded in a layer
of charcoal a few inches deep, instead of being prevented
from decaying as it has hitherto been supposed that they
would be by the supposed antiseptic powers of the
charcoal, they are found by Dr. Stenhouse to decay much
faster, whilst at the same time, no offensive effluvia are
evolved. The deodorizing powers of charcoal are thus
established in a way they never have been before; but at
the same time it is shown that the addition of charcoal to
sewage refuse lessens its agricultural value
contemporaneously with the lessening of odor. From
these observations, which have been fully verified, it
appears that by strewing charcoal coarsely powdered to
the extent of a few inches, over church-yards, or by
placing it inside the coffins of the dead, the escape of
noisome and poisonous exhalations may be totally
prevented. The charcoal respirator embodies this
important discovery. It is certain that many of the
miasma, malaria and infectious matters which propagate
disease in the human subjects, enter the body by the
lungs, and impregnating the blood there, are carried with
it throughout the entire body, which they thus poison.
These miasma are either gases and vapors or bodies
which, like fine light dust, are readily carried through the
air; moreover, they are readily destroyed by oxidizing
agents, which convert them into harmless, or at least non-
poisonous substances, such as water, carbonic acid and
nitrogen. There is every reason, therefore, for believing
that charcoal will oxidize and destroy such miasma as
effectually as it does sulphuretted hydrogen or
hydrosulphuret of ammonia, and thus prevent their
reaching and poisoning the blood. The intention
accordingly is that those who are exposed to noxious
vapors, or compelled to breathe infected atmospheres,

shall wear the charcoal respirator, with a view to arrest
and destroy the volatile poisons contained in these. Some
of the non-obvious applications of the respirator were
then referred to:
“1. Certain of the large chemical manufacturers in
London are now supplying their workmen with the
charcoal respirators as a protection against the more
irritating vapors to which they are exposed.
“2. Many deaths have occurred among those
employed to explore the large drains and sewers of
London from exposure to sulphuretted hydrogen, etc. It
may be asserted with confidence that fatal results from
exposure to the drainage gases will cease as soon as the
respirator is brought into use.
“3. In districts such as the Campagna of Rome, where
malaria prevails and to travel during night or to sleep in
which is certainly followed by an attack of dangerous and
often fatal ague, the wearing of the respirator even for a
few hours may be expected to render the marsh poison
harmless.
“4. Those, who as clergymen, physicians or legal
advisers, have to attend the sick-beds of sufferers from
infectious disorders, may, on occasion, avail themselves
of the protection afforded by Dr. Stenhouse’s instrument
during their intercourse with the sick.
“5. The longing for a short and decisive war has led to
the invention of ‘a suffocating bombshell,’ which on
bursting, spreads far and wide an irrespirable or
poisonous vapor; one of the liquids proposed for the shell
is the strongest ammonia, and against this it is believed
that the charcoal respirator may defend our soldiers. As
likely to serve this end, it is at present before the Board of
Ordnance.

“Dr. Wilson stated, in conclusion, that Dr. Stenhouse
had no interest but a scientific one in the success of the
respirators. He had declined to patent them, and desired
only to apply his remarkable discoveries to the abatement
of disease and death. Charcoal had long been used in
filters to render poisonous water wholesome; it was now
to be employed to filter poisonous air.”

CHAPTER II
MODERN DEVELOPMENT
OF GAS WARFARE
The use of toxic gas in the World War dates from April 22, 1915, when
the Germans launched the first cylinder attack, employing chlorine, a
common and well known gas. Judging from the later experience of the
Allies in perfecting this form of attack, it is probable that plans for this
attack had been under way for months before it was launched. The
suggestion that poisonous gases be used in warfare has been laid upon Prof.
Nernst of the University of Berlin (Auld, “Gas and Flame,” page 15), while
the actual field operations were said to have been under the direction of
Prof. Haber of the Kaiser Wilhelm Physical Chemical Institute of Berlin.
Some writers have felt that the question of preparation had been a matter of
years rather than of months, and refer to the work on industrial gases as a
proof of their statement. The fact that the gas attack was not more
successful, that the results to be obtained were not more appreciated, and
that better preparation against retaliation had not been made, argues against
this idea of a long period of preparation, except possibly in a very desultory
way. That such was the case is most fortunate for the allied cause, for had
the German high command known the real situation at the close of the first
gas attack, or had that attack been more severe, the outcome of the war of
1914 would have been very different, and the end very much earlier.

First Gas Attack

The first suggestion of a gas attack came to the British Army through
the story of a German deserter. He stated that the German Army was
planning to poison their enemy with a cloud of gas, and that the cylinders
had already been installed in the trenches. No one listened to the story,
because, first of all, the whole procedure seemed so impossible and also
because, in spite of the numerous examples of German barbarity, the
English did not believe the Germans capable of such a violation of the

Hague rules of warfare. The story appeared in the summary of information
from headquarters (“Comic Cuts”) and as Auld says “was passed for
information for what it is worth.” But the story was true, and on the
afternoon of the 22nd of April, all the conditions being ideal, the beginning
of “gas warfare” was launched. Details of that first gas attack will always
be meager, for the simple reason that the men who could have told about it
all lie in Flanders field where the poppies grow.
The place selected was in the northeast part of the Ypres salient, at that
part of the line where the French and British lines met, running southward
from where the trenches left the canal near Boesinghe. The French right
was held by the —— Regiment of Turcos, while on the British left were the
Canadians. Auld describes the attack as follows:
“Try to imagine the feelings and the condition of the
colored troops as they saw the vast cloud of greenish-
yellow gas spring out of the ground and slowly move
down wind towards them, the vapor clinging to the earth,
seeking out every hole and hollow and filling the trenches
and shell holes as it came. First wonder, then fear; then,
as the first, fringes of the cloud enveloped them and left
them choking and agonized in the fight for breath—
panic. Those who could move broke and ran, trying,
generally in vain, to outstrip the cloud which followed
inexorably after them.”
It is only to be expected that the first feeling connected with gas warfare
was one of horror. That side of it is very thrillingly described by Rev. O. S.
Watkins in the Methodist Recorder (London). After describing the
bombardment of the City of Ypres from April 20th to 22nd he relates that in
the midst of the uproar came the poison gas!

Fig. 1.—French Gas Attack as seen from an Aeroplane.
The French front, second and third line trenches are plainly visible.
The gas is seen issuing over a wide front from the front line and
drifting towards the German lines.

“Going into the open air for a few moments’ relief
from the stifling atmosphere of the wards, our attention
was attracted by very heavy firing to the north, where the
line was held by the French. Evidently a hot fight—and
eagerly we scanned the country with our field glasses
hoping to glean some knowledge of the progress of the
battle. Then we saw that which almost caused our hearts
to stop beating—figures running wildly and in confusion
over the fields.
“‘The French have broken,’ we exclaimed. We hardly
believed our words.... The story they told we could not
believe; we put it down to their terror-stricken imaginings

—a greenish-gray cloud had swept down upon them,
turning yellow as it traveled over the country, blasting
everything it touched, shriveling up the vegetation. No
human courage could face such a peril.
“Then there staggered into our midst French soldiers,
blinded, coughing, chests heaving, faces an ugly purple
color—lips speechless with agony, and behind them, in
the gas-choked trenches, we learned that they had left
hundreds of dead and dying comrades. The impossible
was only too true.
“It was the most fiendish, wicked thing I have ever
seen.”
It must be said here, however, that this was true only because the French
had no protection against the gas. Indeed, it is far from being the most
horrible form of warfare, provided both sides are prepared defensively and
offensively. Medical records show that out of every 100 Americans gassed
less than two died, and as far as records of four years show, very few are
permanently injured. Out of every 100 American casualties from all forms
of warfare other than gas more than 25 per cent died, while from 2 to 5 per
cent more are maimed, blinded or disfigured for life. Various forms of gas,
as will be shown in the following pages, make life miserable or vision
impossible to those without a mask. Yet they do not kill.
Thus instead of gas warfare being the most horrible, it is the most
humane where both sides are prepared for it, while against savage or
unprepared peoples it can be made so humane that but very few casualties
will result.
The development of methods of defense against gas will be discussed in
a later chapter. It will suffice to say here that, in response to an appeal from
Lord Kitchener, a temporary protection was quickly furnished the men. This
was known as the “Black Veiling” respirator, and consisted of a cotton pad
soaked in ordinary washing soda solution, and later, in a mixture of washing
soda and “hypo,” to which was added a little glycerine. These furnished a
fair degree of protection to the men against chlorine, the only gas used in
the early attacks.

Phosgene Introduced

The use of chlorine alone continued until the introduction on December
19, 1915, of a mixture of phosgene with the chlorine. This mixture offered
many advantages over the use of chlorine alone (see Chapter VI).
The Allies were able, through warning of the impending use of
phosgene, to furnish a means of protection against it. It was at this time that
the p and the ph helmets were devised, the cotton filling being impregnated
with sodium phenolate and later with a mixture of sodium phenolate and
hexamethylenetetramine. This helmet was used until the Standard Box
Respirator was developed by the late Lt. Col. Harrison.

Allies Adopt Gas

For a week or two the Allies were very hesitant about adopting gas
warfare. However, when the repeated use of gas by the Germans made it
evident that, in spite of what the Hague had to say about the matter, gas was
to be a part, and as later developments showed, a very important part of
modern warfare, they realized there was no choice on their part and that
they had to retaliate in like manner. This decision was reached in May of
1915. It was followed by the organization of a Gas Service and intensive
work on the part of chemists, engineers and physiologists. It was September
25, 1915, however, before the English were in a position to render a gas
attack. From then on the Service grew in numbers and in importance,
whether viewed from the standpoint of research, production, or field
operations.
The Allies of course adopted not only chlorine but phosgene as well,
since both were cheap, easy of preparation and effective. They felt during
the early part of the War that they should adopt a substance that would kill
instantly, and not one that would cause men to suffer either during the
attack or through symptoms which would develop later in a hospital. For
this reason a large amount of experimental work was carried out on
hydrocyanic acid, particularly by the French. Since this gas has a very low
density, it was necessary to mix with it substances which would tend to
keep it close to the ground during the attack. Various mixtures, all called
“vincennite,” were prepared,—chloroform, arsenic trichloride and stannic

chloride being used in varying proportions with the acid. It was some time
before it was definitely learned that these mixtures were far from being
successful, both from the standpoint of stability and of poisonous
properties. While the French actually used these mixtures in constantly
decreasing quantities on the field for a long time, they were ultimately
abandoned, though not until American chemists had also carried out a large
number of tests. However, following the recommendation of the American
Gas Service in France in December, 1917, no vincennite was ever
manufactured by the United States.

Lachrymators

Almost simultaneously with the introduction of the gas wave attacks, in
which liquefied gas under pressure was liberated from cylinders, came the
use of lachrymatory or tear gases. These, while not very poisonous in the
concentrations used, were very effective in incapacitating men through the
effects produced upon their eyes. The low concentration required (one part
in ten million of some lachrymators is sufficient to make vision impossible
without a mask) makes this form of gas warfare very economical as well as
very effective. Even if a mask does completely protect against such
compounds, their use compels an army to wear the mask indefinitely, with
an expenditure of shell far short of that required if the much more deadly
gases were used. Thus Fries estimates that one good lachrymatory shell will
force wearing the mask over an area that would require 500 to 1000
phosgene shell of equal size to produce the same effect. While the number
of actual casualties will be very much lower, the total effect considered
from the standpoint of the expenditure of ammunition and of the objectives
gained, will be just as valuable. So great is the harassing value of tear and
irritant gases that the next war will see them used in quantities
approximating that of the more poisonous gases.
The first lachrymator used was a mixture of the chlorides and bromides
of toluene. Benzyl chloride and bromide are the only valuable substances in
this mixture, the higher halogenated products having little or no
lachrymatory value. Xylyl bromide is also effective. Chloroacetone and
bromoacetone are also well known lachrymators, though they are expensive
to manufacture and are none too stable. Because of this the French modified

their preparation and obtained mixtures to which they gave the name
“martonite.” This is a mixture of 80 per cent bromoacetone and 20 per cent
chloroacetone, and can be made with nearly complete utilization of the
halogen. Methyl ethyl ketone may also be used, which gives rise to the
“homomartonite” of the French. During the early part of the War, when
bromine was so very expensive, the English developed ethyl iodoacetate.
This was used with or without the addition of alcohol. Later the French
developed bromobenzyl cyanide, C₆H₅CH(Br)CN. This was probably the
best lachrymator developed during the War and put into large scale
manufacture, though very little of it was available on the field of battle
before the War ended. Chloroacetophenone would have played an important
part had the War continued.

Disadvantage of Wave Attacks

As will be discussed more fully in the chapters on “The Tactics of Gas,”
the wave attacks became relatively less important in 1916 through the use
of gas in artillery shell. This was the result of many factors. Cloud gas
attacks, as carried out under the old conditions, required a long time for the
preliminary preparations, entailed a great deal of labor under the most
difficult conditions, and were dangerous of execution even when weather
conditions became suitable. The difficulties may be summarized as follows:
(1) The heavy gas cylinders used required a great deal of transportation,
and not only took the time of the Infantry but rendered surprise attacks
difficult owing both to the time required and to the unusual activity behind
the lines that became, with the development of aeroplanes, more and more
readily discerned.
(2) Few gases were available for wave attacks—chlorine, phosgene and,
to a less extent, chloropicrin proving to be the only ones successfully used
by either the Allies or the Germans. Hydrogen sulfide, carbon monoxide
and hydrocyanic acid gas were suggested and tried, but were abandoned for
one reason or another.
(3) Gas cloud attacks were wholly dependent upon weather conditions.
Not only were the velocity and direction of the wind highly important as
regards the successful carrying of the wave over the enemy’s line, but also

to prevent danger to the troops making the attack due to a possible shift of
the wind, which would carry the gas back over their own line.
(4) The use of gas in artillery shell does not require especially trained
troops inasmuch as gas shell are fired in the same manner as ordinary shell,
and by the same gun crews. Moreover, since artillery gas shell are used
generally only for ranges of a mile or more, the direction and velocity of the
wind are of minor importance. Another factor which adds to the advantage
of artillery shell in certain cases is the ability to land high concentrations of
gas suddenly upon a distant target through employing a large number of the
largest caliber guns available for firing gas.
Notwithstanding the above named disadvantages of wave attacks it was
felt by the Americans from the beginning that successful gas cloud attacks
were so fruitful in producing casualties and were such a strain upon those
opposed to it, that they would continue. Furthermore, since artillery shell
contain about 10 per cent gas, while gas cylinders may contain 50 per cent,
or even more of the total weight of the cylinder, the efficiency of a cloud
gas attack for at least the first mile of the enemy’s territory is far greater
than that of the artillery gas attack. It was accordingly felt that the only
thing necessary to make cloud gas attacks highly useful and of frequent
occurrence in the future was the development of mobile methods—methods
whereby the gas attack could be launched on the surface of the ground and
at short notice. For these reasons gas wave attacks may be expected to
continue and to eventually reach a place of very decided importance in
Chemical Warfare.

Gas Shell

The firing of gas in artillery shell and in bombs has another great
advantage over the wave attack just mentioned. There is a very great
latitude in the choice of those gases which have a high boiling point or
which, at ordinary temperatures, are solids. Mustard gas is an example of a
liquid with a high boiling point, and diphenylchloroarsine an example of a
gas that is ordinarily solid. For the above reason the term “gas warfare” was
almost a misnomer at the close of the War, and today is true only in the
sense that all the substances used are in a gaseous or finely divided

condition immediately after the shell explode or at least when they reach
the enemy.

Projector Attacks

Still another method of attack, developed by the British and first used
by them in July, 1917, was the projector (invented by Captain Livens). This
was used very successfully up to the close of the War, and though the
German attempted to duplicate it, his results were never as effective. The
projector consists of a steel tube of uniform cross section, with an internal
diameter of about 8 inches. By using nickel steel the weight may be
decreased until it is a one man load. The projector was set against a pressed
steel base plate (about 16 inches in diameter) placed in a very shallow
trench.

Fig. 2.—Livens’ Projector.
The Type shown is an 18 cm. German Gas Projector,
captured during the 2d Battle of the Marne.

Until about the close of the war projectors were installed by digging a
triangular trench deep enough to bring the muzzles of the projectors nearly
level with the surface of the ground. They were then protected by sand bags
or canvas covers, or camouflaged with wire netting to which colored bits of
cloth were tied to simulate leaves and shadows. The projectors were fired
by connecting them in series with ordinary blasting machines operated by
hand from a convenient point in the rear. The digging in of the projectors in
No Man’s Land or very close to it was a dangerous and laborious
undertaking. The Americans early conceived the idea that projectors could
be fired just as accurately by digging a shallow trench just deep enough to
form a support for the base plate, and then supporting the outer ends of the

projector on crossed sticks or a light frame work of boards. This idea
proved entirely practical except for one condition. It was found necessary to
fire with a single battery all the projectors near enough together to be
disturbed by the blast from any portion of them. Inasmuch as most of the
blasting machines used for firing had a capacity of only 20 to 30 projectors,
it was necessary to so greatly scatter a large projector attack that the method
was very little used. However, investigations were well under way at the
close of the War to develop portable firing batteries that would enable the
discharge of at least 100 and preferably 500 projectors at one time. By this
arrangement a projector attack could be prepared and launched in two to
four hours, depending upon the number of men available. This enabled the
attack to be decided upon in the evening (if the weather conditions were
right), and to have the attack launched before morning, thereby making it
impossible for aeroplane observers, armed with cameras, to discover the
preparation for the projector attack. Since the bombs used in the projector
may carry as high as 30 pounds of gas (usually phosgene), some idea of the
amount of destruction may be gained when it is known that the British fired
nearly 2500 at one time into Lens.

Stokes’ Mortar

Another British invention is the Stokes’ gun or trench mortar. The range
of this gun is about 800 to 1000 yards. It is therefore effective only where
the front lines are relatively close together. The shell consists of a case
containing the high explosive, smoke material or gas, fitted to a base filled
with a high charge of propelling powder. The shell is simply dropped into
the gun. At the bottom of the gun there is a projection or stud that strikes the
primer, setting off the small charge and expelling the projectile. In order to
obtain any considerable concentration of gas in a particular locality, it is
necessary to fire the Stokes’ continuously (15 shots per minute being
possible under battle conditions) for two to five minutes since the bomb
contains only seven pounds of gas.

Superpalite

It is believed that the first gas shell contained lachrymators or tear
gases. Although the use of these shell continued up to and even after the

introduction of mustard gas, they gradually fell off in number—the true
poison gas shell taking their place. Towards the end of 1915 Auld states that
the Germans were using chloromethyl chloroformate (palite) in shell. In
1916, during the battle of the Somme, palite was replaced by superpalite
(trichloromethyl chloroformate, or diphosgene) which is more toxic than
palite, and about as toxic as phosgene. It has the advantage over phosgene
of being much more persistent. In spite of the fact that American chemists
were not able to manufacture superpalite on a large scale, or at least so
successfully that it would compete in price with other war gases, the
Germans used large quantities of it, alone and mixed with chloropicrin, in
shell of every caliber up to and including the 15 cm. Howitzer.

Fig. 3.—Stokes’ Mortar.

Chloropicrin

The next gas to be introduced was chloropicrin, trichloronitromethane
or “vomiting gas.” It has been stated that a mixture of chloropicrin (25 per
cent) and chlorine (75 per cent) has been used in cloud attacks, but the high
boiling point of chloropicrin (112° C.) makes its considerable use for this
purpose very unlikely. The gas is moderately toxic and somewhat
lachrymatory, but it was mainly used because of its peculiar property of
causing vomiting when inhaled. Its value was further increased at first
because it was particularly difficult to prepare a charcoal which would
absorb it. Its peculiar properties are apt to cause it to be used for a long
time.

Sneezing Gas

During the summer of 1917 two new and very important gases were
introduced, and, as before, by the Germans. One of these was
diphenylchloroarsine, “sneezing gas” or “Blue Cross.” This is a white solid
which was placed in a bottle and embedded in TNT in the shell. Upon
explosion of the shell the solid was atomized into very fine particles. Since
the ordinary mask does not remove smoke or mists, the sneezing gas
penetrates the mask and causes violent sneezing. The purpose, of course, is
to compel the removal of the mask in an atmosphere of lethal gas. (The
firing regulations prescribed its use with phosgene or other lethal shell.) The
latest type masks protect against this dust, but as it is extraordinarily
powerful, its use will continue.

Mustard Gas

The second gas was dichloroethyl sulfide, mustard gas, Yellow Cross or
Yperite. Mustard gas, as it is commonly designated, is probably the most
important single poisonous substance used in gas warfare. It was first used
by the Germans at Ypres, July 12, 1917. The amount of this gas used is
illustrated by the fact that at Nieuport more than 50,000 shell were fired in
one night, some of which contained nearly three gallons of the liquid.
Mustard gas is a high boiling and very persistent material, which is
characterized by its vesicant (skin blistering) action. Men who come in
contact with it, either in the form of fine splashes of the liquid or in the

form of vapor, suffer severe blistering of the skin. The burns appear from
four to twelve hours after exposure and heal very slowly. Ordinary clothing
is no protection against either the vapor or the liquid. Other effects will be
considered in Chapter IX.
Since then there has been no important advance so far as new gases are
concerned. Various arsenic derivatives were prepared in the laboratory and
tested on a small scale. The Germans did actually introduce
ethyldichloroarsine and the Americans were considering
methyldichloroarsine. Attempts were made to improve upon mustard gas
but they were not successful.

Lewisite

It is rather a peculiar fact that so few new chemical compounds were
used as war gases. Practically all the substances were well known to the
organic chemist long before the World War. One of the most interesting and
valuable of the compounds which would have found extensive use had the
War continued, is an arsenic compound called Lewisite from its discoverer,
Capt. W. Lee Lewis, of Northwestern University. The chemistry of this
compound is discussed in Chapter X. Because of the early recognized value
of this compound, very careful secrecy was maintained as to all details of
the method of preparation and its properties. As a result, strange stories
were circulated about its deadly powers. Characteristic of these was the
story that appeared in the New York Times early in 1919. Now that the
English have published the chemical and pharmacological properties, we
can say that, although Lewisite was never proven on the battle field,
laboratory tests indicate that we have here a very powerful agent. Not only
is it a vesicant of about the same order of mustard gas, but the arsenical
penetrates the skin of an animal, and three drops, placed on the abdomen of
a mouse, are sufficient to kill within two to three hours. It is also a powerful
respiratory irritant and causes violent sneezing. Its possible use in aeroplane
bombs has led General Fries to apply the term “The Dew of Death” to its
use in this way.

Camouflage Gases

Considerable effort was spent on the question of camouflage gases. This
involved two lines of research:
(1) To prevent the recognition of a gas when actually present on the
field, by masking its odor.

TABLE I
Chemical Warfare Gases
Means of
Chemical Belligerent Effect
Projection
Acrolein (allylaldehyde) French Lachrymatory Hand grenades
Lethal
Arsenic chloride (In mixtures. See below)
Benzyl iodide French Lachrymatory Artillery shell
Benzyl chloride French Lachrymatory Artillery shell
Bromoacetone French Lachrymatory Artillery shell
Lethal
Bromobenzylcyanide French Lachrymatory Artillery shell
Bromomethylethylketone German Lachrymatory Artillery shell
Lethal Artillery shell
Benzyl bromide German Lachrymatory Artillery shell
French
Chlorine German Lethal Cylinders
British (cloud gas)
French
American
Chlorosulfonic acid German Irritant Hand grenades,
light minenwerfer
Chloroacetone French Lachrymatory Artillery shell
Chlorobenzene (as solvent) German Lachrymatory Artillery shell
Chloropicrin British Lethal Artillery shell
French Lachrymatory Trench mortar bombs
German Projectors
American
Cyanogen bromide Austrian Lethal Artillery shell
Dichloromethylether German Lachrymatory Artillery shell
(as solvent)
Diphenylchloroarsine German Sternutatory Artillery shell
Lethal
Dichloroethylsulfide German Vesicant Artillery shell
French Lethal
British Irritant
American
Ethyldichloroarsine German Lethal Artillery shell
Ethyliodoacetate British Lachrymatory Artillery shell,
4-in. Stokes’ mortars,

Means of
Chemical Belligerent Effect
Projection
hand grenades
Hydrocyanic acid French (In mixtures. See below) Lachrymatory
Methylchlorosulfonate German Irritant Minenwerfer
Monochloromethylchloroformate French Lachrymatory Lachrymatory
Phosgene British Lethal Projectors,
French trench mortars,
German artillery shell,
American cylinders
Phenylcarbylaminechloride German Lachrymatory Artillery shell
Irritant
Trichlormethylchloroformate German Lethal Artillery shell
Stannic chloride British Irritant Hand grenades
French Cloud forming Artillery
American Projectors
4-in. Stokes’
mortar bombs
Sulfuric anhydride German Irritant Hand grenades,
minenwerfer,
artillery shell
Xylyl bromide German Lachrymatory Artillery shell

TABLE I—Continued
Means of
Chemical Belligerent Effect
Projection
Mixtures[4]
Bromoacetone (80%) and French Lachrymatory Artillery shell
Chloroacetone (20%) Lethal
Chlorine (50%) and British Lethal
Cylinders
Phosgene (50%) German
Chlorine (70%) and Lethal
British Cylinders
Chloropicrin (30%) Lachrymatory
Chloropicrin (65%) and Lethal
British Cylinders
Hydrogen sulfide (35%) Lachrymatory
Chloropicrin (80%) and British Lethal Artillery shell
Stannic chloride (20%) French Lachrymatory Trench mortar bombs
American Irritant Projectors
Chloropicrin (75%) and Lethal Artillery shell
Phosgene (25%) British Lachrymatory Trench mortar bombs,
projectors
Dichloroethyl sulfide (80%) German Vesicant
and Chlorobenzene (20%) French Lethal Artillery shell
British
American
Ethyl carbazol (50%) and German Sternutatory Artillery shell

Means of
Chemical Belligerent Effect
Projection
Diphenylcyanoarsine (50%) Lethal
Ethyldichloroarsine (80%) and Lethal
German Artillery shell
Dichloromethylether (20%) Lachrymatory
Ethyliodoacetate (75%) and Artillery shell,
Alcohol (25%) British Lachrymatory 4-in. Stokes’ mortars,
hand grenades
Hydrocyanic acid (55%)
Chloroform (25%) and British Lethal Artillery shell
Arsenious chloride (20%)
Hydrocyanic acid (50%),
Arsenious chloride (30%), French Lethal Artillery shell
Stannic chloride (15%) and
Chloroform (5%)
Phosgene (50%) and
British Lethal Artillery shell
Arsenious chloride (50%)
Dichloroethyl sulfide (80%) German Vesicant
and Carbon tetrachloride (20%) French Lethal Artillery shell
British
American
Phosgene (60%) and British Lethal
Artillery shell
Stannic chloride (40%) French Irritant
Methyl sulfate (75%) and Lachrymatory
French Artillery shell
Chloromethyl sulfate (25%) Irritant

(2) To simulate the presence of a toxic gas. This may be done either by
using a substance whose odor in the field strongly suggests that of the gas
in question, or by so thoroughly associating a totally different odor with a
particular “gas” in normal use that, when used alone, it still seems to imply
the presence of that gas. This use of imitation gas would thus be of service
in economizing the use of actual “gas” or in the preparation of surprise
attacks.
While there was some success with this kind of “gas,” very few such
attacks were really carried out, and these were in connection with projector
attacks.

Gases Used

Table I gives a list of all the gases used by the various armies, the nation
which used them, the effect produced and the means of projection used.

Table II gives the properties of the more important war cases (compiled
by Major R. E. Wilson, C. W. S.).
The gases used by the Germans may also be classified by the names of
the shell in which they were used. Table III gives such a classification.

Markings for American Shell

In selecting markings for American chemical shell, red bands were used
to denote persistency, white bands to denote non-persistency and lethal
properties, yellow bands to denote smoke, and purple bands to denote
incendiary action. The number of bands indicates the relative strength of the
property indicated; thus, three red bands denote a gas more persistent than
one red band.
The following shell markings were actually used:
1 White Diphenylchloroarsine
2 White Phosgene
1 White, 1 red Chloropicrin
1 White, 1 red, 1 white 75% Chloropicrin, 25% Phosgene
1 White, 1 red, 1 yellow 80% Chloropicrin, 20% Stannic
Chloride
1 Red Bromoacetone
2 Red Bromobenzylcyanide
3 Red Mustard Gas
1 Yellow White Phosphorus
2 Yellow Titanium Tetrachloride

TABLE II
Physical Constants of Important War Gases

Liquid
Vapor
Density Melting Boiling
Molecular Pressure
Name of Gas Formula at 20° C. point, point,
Weight at 20° C.
under Own °C. °C.
(mm. Hg)
Pressure
Bromoacetone C₃H₅BrO 136.98 1.7(?) - 54 126 9(?)
Carbon monoxide CO 28.00 (Gas) -207 -190 (Gas)
Cyanogen bromide BrCN 106.02 2.01 52 61.3 89
Cyanogen chloride ClCN 61.56 1.186 -6 15 1002
Chlorine Cl₂ 70.92 1.408 -101.5 33.6 5126
Chloropicrin Cl₃C(NO₂) 164.39 1.654 - 69.2 112 18.9
Dichloroethyl sulfide (CH₃CHCl₂)S 169.06 1.274 12.5 216 .06
Diphenylchloroarsine (C₆H₅)₂AsCl 264.56 1.422 44 333 .0025
Hydrocyanic acid HCN 27.11 .697 - 14 26.1 603
Phenyldichloroarsine C₆H₅AsCl₂ 210.96 1.640 ... 253 .022
Phosgene COCl₂ 98.92 1.38 ... 8.2 1215
Stannic chloride SnCl₄ 260.54 2.226 - 33 114 18.58
Superpalite CCl₃COOCl 197.85 1.65 ... 128 10.3
Xylyl bromide ( CH₃)C₆H₄CH₂Br 185.03 1.381 -2 214.5 ...

TABLE III
German Shell
Nature of
Name of Shell Shell Filling
Effect
B-shell [K₁ shell (White B or BM)] Bromoketone Lachrymator
(Bromomethylethyl ketone)
Blue Cross (a) Diphenylchloroarsine Sternutator
(b) Diphenylcyanoarsine Sternutator
(c) Diphenylchloroarsine,
Ethyl carbazol
C-shell (Green Cross) (White C) Superpalite Asphyxiant
D-shell (White D) Phosgene Lethal
(a) Superpalite
Green Cross Asphyxiant
(b) Phenylcarbylaminechloride
Superpalite 65%,
Green Cross 1 Asphyxiant
Chloropicrin 35%
Superpalite,
Green Cross 2 Phosgene, Asphyxiant
Diphenylchloroarsine
Green Cross 3 Ethyldichloroarsine,
(Yellow Cross 1) Methyldibromoarsine, Asphyxiant
Dichloromethyl ether
K-shell (Yellow) Chloromethylchloroformate Asphyxiant
(Palite)
Xylyl bromide,
T-shell (Black or green T) Lachrymator
Bromo ketone

Nature of
Name of Shell Shell Filling
Effect
Mustard gas,
Yellow Cross Vesicant
Diluent (CCl₄, C₆H₅Cl, C₆H₅NO₂)
Yellow Cross 1 See Green Cross 3

CHAPTER III
DEVELOPMENT OF THE CHEMICAL WARFARE
SERVICE
Modern chemical warfare dates from April 22, 1915. Really, however, it
may be said to have started somewhat earlier, for Germany undoubtedly had
spent several months in perfecting a successful gas cylinder and a method
of attack. The Allies, surprised by such a method of warfare, were forced to
develop, under pressure, a method of defense, and then, when it was finally
decided to retaliate, a method of gas warfare. “Offensive organizations were
enrolled in the Engineer Corps of the two armies and trained for the purpose
of using poisonous gases; the first operation of this kind was carried out by
the British at the battle of Loos in September, 1915.
“Shortly after this the British Army in the field amalgamated all the
offensive, defensive, advisory and supply activities connected with gas
warfare and formed a ‘Gas Service’ with a Brigadier General as Director.
This step was taken almost as a matter of necessity, and because of the
continually increasing importance of the use of gas in the war (Auld).”
At once the accumulation of valuable information and experience was
started. Later this was very willingly and freely placed at the disposal of
American workers. Too much cannot be said about the hearty co-operation
of England and France. Without it and the later exchange of information on
all matters regarding gas warfare, the progress of gas research in all the
allied countries would have been very much retarded.
While many branches of the American Army were engaged in following
the progress of the war during 1915-1916, the growing importance of gas
warfare was far from being appreciated. When the United States declared
war on Germany April 6, 1917, there were a few scattered observations on
gas warfare in various offices of the different branches, but there was no
attempt at an organized survey of the field, while absolutely no effort had
been made by the War Department to inaugurate research in a field that later
had 2,000 men alone in pure research work. Equally important was the fact

that no branch of the Service had any idea of the practical methods of gas
warfare.
The only man who seemed to have the vision and the courage of his
convictions was Van H. Manning, Director of the Bureau of Mines. Since
the establishment of the Bureau in 1908 it had maintained a staff of
investigators studying poisonous and explosive gases in mines, the use of
self-contained breathing apparatus for exploring mines filled with noxious
gases, the treatment of men overcome by gas, and similar problems. At a
conference of the Director of the Bureau with his Division Chiefs, on
February 7, 1917, the matter of national preparedness was discussed, and
especially the manner in which the Bureau could be of most immediate
assistance with its personnel and equipment. On February 8, the Director
wrote C. D. Walcott, Chairman of the Military Committee of the National
Research Council, pointing out that the Bureau of Mines could immediately
assist the Navy and the Army in developing, for naval or military use,
special oxygen breathing apparatus similar to that used in mining. He also
stated that the Bureau could be of aid in testing types of gas masks used on
the fighting lines, and had available testing galleries at the Pittsburgh
experiment station and an experienced staff. Dr. Walcott replied on
February 12 that he was bringing the matter to the attention of the Military
Committee.
A meeting was arranged between the Bureau and the War College, the
latter organization being represented by Brigadier General Kuhn and Major
L. P. Williamson. At this conference the War Department enthusiastically
accepted the offer of the Bureau of Mines and agreed to support the work in
every way possible.
The supervision of the research on gases was offered to Dr. G. A.
Burrell, for a number of years in charge of the chemical work done by the
Bureau in connection with the investigation of mine gases and natural gas.
He accepted the offer on April 7, 1917. The smoothness with which the
work progressed under his direction and the importance of the results
obtained were the result of Colonel Burrell’s great tact, his knowledge of
every branch of research under investigation and his imagination and
general broad-mindedness.

Once, however, that the importance of gas warfare had been brought to
the attention of the chemists of the country, the response was very eager and
soon many of the best men of the university and industrial plants were
associated with Burrell in all the phases of gas research. The staff grew very
rapidly and laboratories were started at various points in the East and
Middle West.
It was immediately evident that there should be a central laboratory in
Washington to co-ordinate the various activities and also to considerably
enlarge those activities under the joint direction of the Army, the Navy and
the Bureau of Mines. Fortunately a site was available for such a laboratory
at the American University, the use of the buildings and grounds having
been tendered President Wilson on April 30, 1917. Thus originated the
American University Experiment Station, later to become the Research
Division of the Chemical Warfare Service.
Meanwhile other organizations were getting under way. The
procurement of toxic gases and the filling of shell was assigned to the
Trench Warfare Section of the Ordnance Department. In June, 1917,
General Crozier, then Chief of the Ordnance Department, approved the
general proposition of building a suitable plant for filling shell with toxic
gas. In November, 1917, it was decided to establish such a plant at
Gunpowder Neck, Maryland. Owing to the inability of the chemical
manufacturers to supply the necessary toxic gases, it was further decided, in
December, 1917, to erect at the same place such chemical plants as would
be necessary to supply these gases. In January, 1918, the name was changed
to Edgewood Arsenal, and the project was made a separate Bureau of the
Ordnance Department, Col. William H. Walker, of the Massachusetts
Institute of Technology, being soon afterwards put in command.
While, during the latter part of the War, gas shell were handled by the
regular artillery, special troops were needed for cylinder attacks, Stokes’
mortars, Livens’ projectors and for other forms of gas warfare. General
Pershing early cabled, asking for the organization and training of such
troops, and recommended that they be placed, as in the English Army, under
the jurisdiction of the Engineer Corps. On August 15, 1917, the General
Staff authorized one regiment of Gas and Flame troops, which was
designated the “30th Engineers,” and was commanded by Major (later

Colonel) E. J. Atkisson. This later became the First Gas Regiment, of the
Chemical Warfare Service.
About this time (September, 1917) the need of gas training was
recognized by the organization of a Field Training Section, under the
direction of the Sanitary Corps, Medical Department. Later it was
recognized that neither the Training Section nor the Divisional Gas Officers
should be under the Medical Department, and, in January, 1918, the
organization was transferred to the Engineer Corps.
All of these, with the exception of the Gas and Flame regiment, were for
service on this side. The need for an Overseas force was recognized and
definitely stated in a letter, dated August 4, 1917. On September 3, 1917, an
order was issued establishing the Gas Service, under the command of Lt.
Col. (later Brigadier General) A. A. Fries, as a separate Department of the
A. E. F. in France. In spite of a cable on September 26th, in which General
Pershing had said
“Send at once chemical laboratory, complete
equipment and personnel, including physiological and
pathological sections, for extensive investigation of gases
and powders....”
it was not until the first of January, 1918, that Colonel R. F. Bacon of the
Mellon Institute sailed for France with about fifty men and a complete
laboratory equipment.
Meantime a Chemical Service Section had been organized in the United
States. This holds the distinction of being the first recognition of chemistry
as a separate branch of the military service in any country or any war. This
was authorized October 16, 1917, and was to consist of an officer of the
Engineers, not above the rank of colonel, who was to be Director of Gas
Service, with assistants, not above the rank of lieutenant colonel from the
Ordnance Department, Medical Department and Chemical Service Section.
The Section itself was to consist of 47 commissioned and 95 non-
commissioned officers and privates. Colonel C. L. Potter, Corps of
Engineers, was appointed Director and Professor W. H. Walker was
commissioned Lieutenant Colonel and made Assistant Director of the Gas
Service and Chief of the Chemical Service Section. This was increased on
Feb. 15, 1918 to 227 commissioned and 625 enlisted men, and on May 6,

1918 to 393 commissioned and 920 enlisted men. Meanwhile Lt. Col.
Walker had been transferred to the Ordnance and Lt. Col. Bogert had been
appointed in his place.
At this time practically every branch of the Army had some connection
with Gas Warfare. The Medical Corps directed the Gas Defense production.
Offense production was in the hands of the Ordnance Department. Alarm
devices, etc., were made by the Signal Corps. The Engineers contributed
their 30th Regiment (Gas and Flame) and the Field Training Section. The
Research Section was still in charge of the Bureau of Mines, in spite of
repeated attempts to militarize it. And in addition, the Chemical Service
Section had been formed primarily to deal with overseas work. While the
Director of the Gas Service was expected to co-ordinate all these activities,
he was given no authority to control policy, research or production.
In order to improve these conditions Major General Wm. L. Sibert, a
distinguished Engineer Officer who built the Gatun Locks and Dam of the
Panama Canal and who had commanded the First Division in France, was
appointed Director of the Chemical Warfare Service on May 11, 1918.
Under his direction the Chemical Warfare Service was organized with the
following Divisions:
Overseas Brigadier General Amos A. Fries
Research Colonel G. A. Burrell
Development Colonel F. M. Dorsey
Gas Defense Production Colonel Bradley Dewey
Gas Offense Production Colonel Wm. H. Walker
Medical Colonel W. J. Lyster
Proving Lt. Col. W. S. Bacon
Administration Brigadier General H. C. Newcomer
Gas and Flame Colonel E. J. Atkisson
The final personnel authorized, though never reached owing to the
signing of the Armistice, was 4,066 commissioned officers and 44,615
enlisted men; this was including three gas regiments of eighteen companies
each.

General Sibert brought with him not only an extended experience in
organizing and conducting big business, but a strong sympathy for the work
and an appreciation of the problem that the American Army was facing in
France. He very quickly welded the great organization of the Chemical
Warfare Service into a whole, and saw to it that each department not only
carried on its own duties but co-operated with the others in carrying out the
larger program, which, had the war continued, would have beaten the
German at his own game.
More detailed accounts will now be given of the various Divisions of
the Chemical Warfare Service.

Administration Division

The Administration Division was the result of the development which
has been sketched in the preceding pages. It is not necessary to review that,
but the organization as of October 19, 1918 will be given:
Major General Wm. L.
Director
Sibert
Staff:
Medical Officer Colonel W. J. Lyster
Ordnance Officer Lt. Col. C. B. Thummel
British Military Mission Major J. H. Brightman
Assistant Director Colonel H. C. Newcomer
Office Administration Major W. W. Parker
Relations Section Colonel M. T. Bogert
Personnel Section Major F. E. Breithut
Contracts and Patents Section Captain W. K. Jackson
Finance Section Major C. C. Coombs
Requirements and Progress Section Capt. S. M. Cadwell

Confidential Information Section Major S. P. Mullikin
Transportation Section Captain H. B. Sharkey
Training Section Lt. Col. G. N. Lewis

Procurement Section Lt. Col. W. J. Noonan
The administrative offices were located in the Medical Department
Building. The function of most of the sections is indicated by their names.
The Industrial Relations Section was created to care for the interests of
the industrial plants which were considered as essential war industries.
Through its activity many vitally important industries were enabled to
retain, on deferred classification or on indefinite furlough, those skilled
chemists without which they could not have maintained a maximum output
of war munitions.
In the same way the University Relations Section cared for the
educational and research institutions. In this way our recruiting stations for
chemists were kept in as active operation as war conditions permitted.
Another important achievement of the Administration Section was to
secure the order from The Adjutant General, dated May 28, 1918, that read:

“Owing to the needs of the military service for a great
many men trained in chemistry, it is considered most
important that all enlisted men who are graduate chemists
should be assigned to duty where their special knowledge
and training can be fully utilized.
“Enlisted men who are graduate chemists will not be
sent overseas unless they are to be employed on chemical
duties....”

While this undoubtedly created a great deal of feeling among the men
who naturally were anxious to see actual fighting in France, it was very
important that this order be carried out in order to conserve our chemical
strength. The following clipping from the September, 1918, issue of The
Journal of Industrial and Engineering Chemistry shows the result of this
order.

“Chemists in Camp

“As the result of the letter from The Adjutant General
of the Army, dated May 28, 1918, 1,749 chemists have
been reported on. Of these the report of action to August
1, 1918, shows that 281 were ordered to remain with their
military organization because they were already
performing chemical duties, 34 were requested to remain
with their military organization because they were more
useful in the military work which they were doing, 12
were furloughed back to industry, 165 were not chemists
in the true sense of the word and were, therefore, ordered
back to the line, and 1,294 now placed in actual chemical
work. There were being held for further investigation of
their qualifications on August 1, 1918, 432 men. The
remaining 23 men were unavailable for transfer, because
they had already received their overseas orders.
“The 1,294 men, who would otherwise be serving in a
purely military capacity and whose chemical training is
now being utilized in chemical work, have, therefore,
been saved from waste.
“Each case has been considered individually, the
man’s qualifications and experience have been studied
with care, the needs of the Government plants and
bureaus have been considered with equal care, and each
man has been assigned to the position for which his
training and qualifications seem to fit him best.
“Undoubtedly, there have been some cases in which
square pegs have been fitted into round holes, but, on the
whole, it is felt that the adjustments have been as well as
could be expected under the circumstances.”

Research Division

The American University Experiment Station, established by the Bureau
of Mines in April, 1917, became July 1, 1918 the Research Division of the
Chemical Warfare Service. For the first five months work was carried out in
various laboratories, scattered over the country. In September, 1917, the

buildings of the American University became available; a little later
portions of the new chemical laboratory of the Catholic University,
Washington, were taken over. Branch laboratories were established in many
of the laboratories of the Universities and industrial plants, of which Johns
Hopkins, Princeton, Yale, Ohio State, Massachusetts Institute of
Technology, Harvard, Michigan, Columbia, Cornell, Wisconsin, Clark,
Bryn Mawr, Nela Park and the National Carbon Company were active all
through the war.
At the time of the signing of the armistice the organization of the
Research Division was as follows:
Col. G. A. Burrell Chief of Research Division
Dr. W. K. Lewis In Charge of Defense Problems
Dr. E. P. Kohler[5] In Charge of Offense Problems
Dr. Reid Hunt Advisor on Pharmacological Problems
In Charge of Editorial Work and Catalytic
Lt. Col. W. D. Bancroft
Research
Lt. Col. A. B. Lamb[6] In Charge of Defense Chemical Research
Dr. L. W. Jones[7] In Charge of Offense Chemical Research
Major A. C. Fieldner In Charge of Gas Mask Research
Major G. A. Richter In Charge of Pyrotechnic Research
Capt. E. K. Marshall[8] In Charge of Pharmacological Research
Dr. A. S. Loevenhart[9] In Charge of Toxicological Research
Major R. C. Tolman In Charge of Dispersoid Research
Major W. S. Rowland[10] In Charge of Small Scale Manufacture
In Charge of Mechanical Research and
Major B. B. Fogler[11]
Development
Captain G. A. Rankin In Charge of Explosive Research
Major Richmond In Charge of Administration Section
Levering

The chief functions of the Research Division were:
1. To prepare and test compounds which might be of
value in gas warfare, determining the properties of these

substances and the conditions under which they might be
effective in warfare.
2. To develop satisfactory methods of making such
compounds as seemed promising (Small Scale).
3. To develop the best methods of utilizing these
compounds.
4. To develop materials which should absorb or
destroy war gases, studying their properties and
determining the conditions under which they might be
effective.
5. To develop satisfactory methods of making such
absorbents as might seem promising.
6. To develop masks, canisters, protective clothing,
etc.
7. To develop incendiaries, smokes, signals, etc., and
the best methods of using the same.

Fig. 4.—American University Experiment Station,
showing Small Scale Plants.

8. To co-operate with the manufacturing divisions in
regard to difficulties arising during the operations of
manufacturing war gases, absorbents, etc.
9. To co-operate with other branches of the
Government, civil and military, in regard to war
problems.
10. To collect and make available to the Director of
the Chemical Warfare Service all information in regard to
the chemistry of gas warfare.
The relation of the various sections may best be shown by outlining the
general procedure used when a new toxic substance was developed.
The substance in question may have been used by the Germans or the
Allies; it may have been suggested by someone outside the station; or the
staff may have thought of it from a search of the literature, from analogy or
from pure inspiration. The Offense Research Section made the substance. If
it was a solid it was sent to the Dispersoid Section, where methods of
dispersing it were worked out. When this had been done, or, at once, if the
compound was a liquid or vapor, it was sent to the Toxicological Section to
be tested for toxicity, lachrymatory power, vesicant action, or other special
properties. If these tests proved the compound to have a high toxicity or a
peculiar physiological behavior, it was then turned over to a number of
different sections.
The Offense Research Section tried to improve the method of
preparation. When a satisfactory method had been found, the Chemical
Production or Small Scale Manufacturing Section endeavored to make it on
a large scale (50 pounds to a ton) and worked out the manufacturing
difficulties. If further tests showed that the substance was valuable, the
manufacture was then given to the Development Division or the Gas
Offense Production Division for large scale production.
Meanwhile the Analytical Section had been working on a method for
testing the purity of the material and for analyzing air mixtures, and the Gas
Mask Section had run tests against it with the standard canisters. If the
protection afforded did not seem sufficient, the Defense Chemical Section
studied changes in the ingredients of the canister or even developed a new

absorbent or mixture of absorbents to meet the emergency. If a change in
the mechanical construction of the canister was necessary, this was referred
to the Mechanical Research Section; this work was especially important in
case the material was to be used as a toxic smoke.
The compound was also sent to the Pyrotechnic Section, which studied
its behavior when fired from a shell, or, if suitable, when used in a cylinder.
If it proved stable on detonation, large field tests were then made by the
Proving Division, in connection with the Pyrotechnic and Toxicological
Sections of the Research Division, to learn the effect when shell loaded
with the compound were fired from guns on a range, with animals placed
suitably in or near the trenches. The Analytical Section worked out methods
of detecting the gas in the field, wherever possible.
The Medical Division, working with the Toxicological and
Pharmacological Sections, studied pathological details, methods of treating
gassed cases, the effect of the gas on the body, and in some cases even
considered other questions, such as the susceptibility of different men.
If the question of an ointment or clothing entered into the matter of
protection, these were usually attacked by several Sections from different
points of view.
Out of the 250 gases prepared by the Offense Chemical Research
Section, very few were sufficiently valuable to pass all of these tests and
thus the number of gases actually put into large scale production were less
than a dozen. This had its advantages, for it made unnecessary a large
number of factories and the training of men in the manufacturing details of
many gases. As one British report stated, “The ultimate object of chemical
warfare should be to produce two substances only; one persistent and the
other non-persistent; both should be lethal and both should be penetrants.”
They might well have added that both should be instantly and powerfully
lachrymatory.
Since most of the work of the Research Division will be covered in
detail in later chapters, only a brief summary of the principal problems will
be given here.
The first and most important problem was the development of a gas
mask. This was before Sections had been organized and was the work of the

entire Division. After comparing the existing types of masks it was decided
that the Standard Box Respirator of the British was the best one to copy.
Because we were entirely new at the game that meant work on charcoal,
soda-lime, and the various mechanical parts of the mask, such as the
facepiece, elastics, eyepieces, mouthpiece, noseclip, hose, can, valves, etc.
The story of the “first twenty thousand” is very well told by Colonel
Burrell.[12]
“The First Twenty Thousand
“About the first of May, 1917, Major L. P.
Williamson, acting as liaison officer between the Bureau
of Mines and the War Department, put the last ounce of
‘pep’ into the organization by asking us to build 20,000
gas masks for shipment overseas. 20,000 masks did not
seem like a very large order. We did not fully appreciate
all the conditions which a war gas mask had to encounter,
so we readily and willingly accepted the order. Then
began a struggle with can manufacturers, buckle makers,
manufacturers of straps, rubber facepieces, eyepieces,
knapsacks, etc. The country was canvassed from the
Atlantic Coast to the Mississippi River for manufacturers
who could turn out the different parts acceptably and in a
hurry.
“Charcoal was made from red cedar by the Day
Chemical Co. of Westline, Pennsylvania; soda-lime
permanganate was manufactured by the General
Chemical Company; knapsacks by the Simmons
Hardware Company in St. Louis; facepieces by the
Goodrich and Goodyear Rubber Companies at Akron;
canisters by the American Can Company; and the
assembly made at one of the plants of the American Can
Company in Long Island City.
“The writer cannot recall all the doubts, fears,
optimism, and enthusiasm felt in turn by different
members of the organization during the fabrication of
those first 20,000 masks. We were performing an

important task for the War Department. Night became
day. Dewey, Lewis, Henderson, Gibbs, and others
stepped from one train to another, and we used the
telephone between Washington and St. Louis or Boston
as freely as we used the local Washington telephone.
“We thought we could improve on the English box
respirator on various points. We made the canister larger,
and have been glad ever since that we did. We thought
the English mouthpiece was too flexible and too small,
and made ours stiff and larger, and were sorry we made
the change. We tested the fillings against chlorine,
phosgene, prussic acid, etc., and had a canister that was
all that was desired for absorbing these gases. But, alas,
we did not know that chloropicrin was destined to be one
of the most important war gases used by the various
belligerents. Further, it was not fully appreciated that the
rubberized cloth used in making the facepiece had to be
highly impermeable against gases, that hardness as much
as anything else was desired in the make-up of the soda-
lime granules in order to withstand rough jolting so that
the fines would not clog the canister, and raise the
resistance to breathing to a prohibitive figure. Neither
was it appreciated at that time by any of the allies, that
the gas mask really should be a be a fighting instrument,
one that men could work hard in, run in, and wear for
hours, without too serious discomfort.
“The first 20,000 masks sent over to England were
completed by the Research Division in record time. As
compared with the French masks, they were far superior,
giving greater protection against chlorine, phosgene,
superpalite, prussic acid, xylyl bromide, etc. The French
mask was of the cloth type, conforming to the face, and
consisting of twenty layers of cheesecloth impregnated
with sodium phenate and hexamethylenetetramine.
Chloropicrin went through this like a shot. Just before the
masks were sent abroad, we received disturbing rumors

of the contemplated use of large quantities of
chloropicrin. The French, apparently, had no intention of
changing the design of their mask, and did not do so for
months to come. We therefore released the masks, they
were sent abroad, and an anxious research group on this
side of the water waited expectantly for the verdict. It
came. A brief cablegram told us what our English cousins
thought of us. It was a subject they had been wrestling
with for two years and a half. They had had battlefield
experience; they had gone through the grief of
developing poor masks into better ones, knew the story
better than we did, and after a thorough test ‘hammered’
the American design unmercifully.
“This experience put the Research Division on its
mettle. Our first attempt had given us the necessary
preliminary experience; cablegrams and reports traveled
back and forth; an expert or two eventually came to this
country from England in response to previous appeals for
assistance, and we turned with adequate information to
the development of a real mask.”

The story of mustard gas is given later. It probably occupied more time
and thought on the part of the Research Division, as well as that of
Edgewood Arsenal and the Development Division, than any other gas.
Diphenylchloroarsine led to the preparation of a series of arsenic
compounds, some more easily prepared and more or less effective.
Cyanogen chloride and cyanogen bromide, reported by the Italians as
having been used by the Germans, were extensively studied.
The Inorganic Section was early interested in special incendiary
materials which were developed for bombs, shells, darts and grenades, and
which were later taken over by the Pyrotechnic Section, and finally adopted
by the Ordnance Department.
In discussing the work one can very well start with the Offense Section.
This Section had two aims in view always, to develop methods of making
the gases used by the Germans more economically than they were making

them, and to develop better gases if possible. When we entered the war,
chlorine, phosgene and chloropicrin were the lethal gases used, while
bromoacetone and xylyl bromide were the lachrymators. It was not a
difficult matter to prepare these. But the introduction of mustard gas in the
summer of 1917 and of diphenylchloroarsine in the autumn of the same
year, not only made our chemists ponder over a manufacturing method, but
also so revised our notions of warfare that the possibility of using other
substances created the need for extensive research. The development of
bromobenzylcyanide by the French likewise opened a new field among
lachrymatory substances.
Colored rockets and smokes were developed for the Navy and Army.
The smoke box was also studied but the work was taken over by the
Pyrotechnic Section.
A large amount of pure inorganic research on arsine and arsenides,
fluorine, hydrofluoric acid and fluorides, cyanides, cyanogen sulfide and
nitrogen tetroxide was carried out, sometimes successfully and at other
times with little or no success.
The Analytical Section not only carried out all routine analyses but
developed methods for many new gases.
The Offense Section worked in very close contact with the Small Scale
Manufacturing Section (Chemical Production Section). Often it happened
that a method, apparently successful in the laboratory, was of no value in
the plant. Small scale plants were developed for mustard gas, hydrocyanic
acid, cyanogen chloride, arsenic trichloride, arsenic trifluoride, magnesium
arsenide, superpalite and bromobenzylcyanide.
The Chemical Defense Section, organized January, 1918, was occupied
with problems relating to protection, such as charcoal, soda-lime, and
special absorbents, eyepieces, smoke filters, efficiency of absorbents, and
special work with mustard gas.
Charcoal demanded extensive research. Raw materials required a world-
wide search, carbonizing methods had to be developed, and impregnating
agents were thoroughly studied. This story is told in Chapter XIII.
Soda-lime was likewise a difficult problem. Starting with the British
formula, the influence of the various factors was studied and a balance

between a number of desirable qualities, absorptive activity, capacity,
hardness, resistance to abrasion, chemical stability, etc., obtained. The final
product consisted of a mixture of lime, cement, kieselguhr, sodium
permanganate and sodium hydroxide.
Equally valuable work was performed in the perfection of two carbon
monoxide absorbents for the Navy. The better of these consisted of a
mixture of suitably prepared oxides which acts catalytically under certain
conditions, and causes the carbon monoxide to react with the oxygen of the
air. Since there are color changes connected with the iodine pentoxide
reaction (the first absorbent) it has been possible to develop this so as to
serve as a very sensitive detector for the presence of carbon monoxide in
air.
While the question of smoke filters was so important that it occupied
the attention of several Sections, the Defense Section developed, as a part
of its work, a standard method of testing and comparing filters, and did a
great deal of work on the preparation of paper for this purpose.
Various problems related to mustard gas were also studied. The question
of a protective ointment was solved as successfully as possible under the
circumstances, but was dropped when it appeared doubtful if under
battlefield conditions of concentration and length of exposure, any ointment
offered sufficient protection to pay for the trouble of applying it. The
removal of mustard gas from clothing was investigated, especially by the
accelerating effect of turkey red oil. Another phase of the work concerned
the destruction of mustard gas on the ground, while a fourth phase related to
the persistency of mustard (and other gases) on the field of battle.
The Gas Mask Research Section concerned itself largely with
developing methods of testing canisters and with routine tests. When one
considers the number of gases studied experimentally, the large number of
experimental canisters developed, all of which were tested against two or
more gases, and further that the Section assisted in the control of the
production at Long Island City, it is seen that this was no small job. In
addition, the effect of various conditions, such as temperature, humidity,
ageing, size of particles, were studied in their relation to the life of
absorbents and canisters. Man tests and mechanical tests will be discussed
in a later chapter. Other studies were concerned with weathering tests of gas

mask fabrics, mustard gas detector, and covering for dugout entrances
(dugout blankets), which were impregnated with a mixture of mineral and
vegetable oils. In studying the course of gases through a canister the “wave
front” method was of great value in detecting defects in canister design and
filling.
The Pyrotechnic Section was composed of a number of units, each with
its own problem. The gas shell was studied, with special reference to the
stability of gases and toxic solids, both on storage and on detonation.
Extensive work was carried out on smoke screens—a Navy funnel, an
Army portable smoke apparatus, using silicon tetrachloride, a grenade, a
Livens, and various shell being developed for that purpose. The smoke
screen was adapted to the tank and the airplane as well as to the funnel of a
ship. Several types of incendiary bombs and darts were perfected. The
liquid fire gun was studied but the results were never utilized because of the
abandonment as useless of that form of warfare. Various forms of signal
lights, flares, rockets and colored smokes were studied and in most cases
specifications were written. Extensive studies were also carried out on gas
shell linings, from which a lead and an enamel lining were evolved. Many
physical properties of war gases and their mixtures were determined.
The Dispersoid Section studied the production of smokes or mists from
various solid and liquid substances. Apparatus were developed to study the
concentration of smoke clouds and their rate of settling. The efficiency of
various filters and canisters was determined, and among other things, a new
smoke candle was perfected.
Mechanical research at first was related to design and construction of a
canister and mask, based on the English type. During the latter part of 1917
the Tissot type of mask was studied and then turned over to the Gas
Defense Division. A Navy Head Mask and canister was perfected. The
horse mask was developed along the lines of the British type, and also a dog
mask of the same general nature. Horse boots were also constructed, though
they never were used at the front. Many Ordnance and Pyrotechnic
problems were also successfully completed, not the least of which was a
noiseless gas cylinder. This section developed the first special poison gas
suit, composed of an oilcloth suit, a mask and helmet and a special canister.

The Manufacturing Development Section had general charge of the
defense problems, and really acted as an emergency section, filling in as
occasion demanded. They developed mustard gas clothing and a horse
mask. They constructed a hydrogen plant at Langley Field, assisted in
solving the difficulties relating to Batchite charcoal at Springfield, Mass.,
and co-operated in the study of paper and felt as filtering materials for
smokes. Towards the close of the war the Section was interested in the
application of the gas mask to the industries.
The Physiological work is discussed under the Medical Division.
The Editorial Section received reports from all the other Sections, from
which a semi-monthly report was written, and distributed to authorized
representatives of the Army and Navy and to our Allies. Reports were also
received from abroad and the information thus received was made available
to the Research Division. As the number of reports increased the work was
collected together into monographs on the various war gases, absorbents,
smokes, etc. After the signing of the armistice these were revised and
increased in number, so that about fifty were finally turned over to the
Director of the Chemical Warfare Service.

Gas Defense Division

The story of the Gas Defense Division is largely the story of the gas
mask. Colonel (then Mr.) Bradley Dewey was in charge of the “first twenty
thousand.” Soon after that work was undertaken, he was commissioned
Major in the Gas Defense Division of the Sanitary Corps and was placed in
charge of the entire manufacturing program. The work of the Division
included the development and manufacture as well as the testing and
inspection of gas masks, and other defense equipment. The magnitude of
the work is seen from the following record of production: 5,692,000
completed gas masks, 3,614,925 of which were produced at the Long Island
City Plant, while the remainder were assembled at the Hero Manufacturing
Company’s Plant at Philadelphia, 377,881 horse masks, 191,388 dugout
blankets, 2,450 protective suits and 1,773 pairs of gloves, 1,246 tons of
protective ointment, 45,906 gas warning signals (largely hand horns),
50,549 trench fans and many oxygen inhalators.

Fig. 5.—The Defective Gas Mask.

Successfully used by the Gas Defense Division to stimulate care in
every part of the operation of the manufacture of Gas Masks.]
The story of the “first twenty thousand” has already been told on page
43. That these masks were far from satisfactory is no reflection upon the
men who made them. Even with the standard design of the British as a
pattern, it was impossible to attain all the knowledge concerning gas masks
in two months. The experience gained in this struggle enabled the Army to
take up the manufacture of gas masks, in July, 1917, with a more complete
realization of the seriousness of the task. The masks were not lost, either,

for they were sent to the various camps as training masks and served a very
useful purpose.
The first order after this was for 1,100,000 masks, to be completed
within a year from date. For this production there was authorized one major,
two captains, and ten lieutenants. How little the problem was understood is
evident when we realize that in the end there were 12,000 employees in the
Gas Defense Plant at Long Island City, N. Y. The first attempts were to
secure these through existing concerns. The Hero Manufacturing Company
of Philadelphia undertook the work and carried on certain portions of it all
through the War. Experience soon showed, however, that because of the
necessity for extreme care in the manufacture and inspection of the mask,
the ordinary commercial organization was not adapted to carry on their
manufacture on the scale necessitated by the Army program. Consequently,
on Nov. 21, 1917, the Secretary of War authorized the establishment of a
government operated plant, and experienced officials were drawn from New
York, Chicago, Boston and other manufacturing centers to carry on the
work. Buildings in Long Island City, not far from the chemical plant
(charcoal and soda lime) at Astoria, were taken over by the officers of the
Gas Defense Service, until in July, 1918, five large buildings were
occupied, having a total floor space of 1,000,000 square feet (23 acres). The
organization grew from the original thirteen officers until it included some
12,000 employees of whom about 8,500 were women. Because of the care
required in all the work, attempt was made to secure, as far as possible,
those who had relatives with the A. E. F. The thought was that their personal
interest in the work would result in greater care in manufacture and
inspection. The personnel was unique in that the authority was apparently
divided between civilian and military, but there was no friction because of
this. The efficiency of the entire organization is shown by the fact that the
masks manufactured at Long Island City cost fifty cents less per mask than
those manufactured under contract.
The first actual shipment (overseas) of box respirators was made from
the Gas Defense Plant on March 4, 1918. From this date the production
increased by leaps and bounds. As mentioned above, between this date and
November 26, when the last mask was manufactured, 3,146,413 masks of
the box respirator type were passed through final inspection in the plant.
The greatest daily production, 43,926 masks, was reached on October 26,

1918. The process of manufacture will be discussed under the chapter on
the Gas Mask.
During the last half of 1918 the Kops Tissot mask was manufactured.
This mask had been perfected during the months preceding August, 1918,
when its manufacture was started. Considerable difficulty was encountered
in its production, but the first mask was completed on September 14, and
between that time and the Armistice, 189,603 masks of this type had been
manufactured.
Along with this manufacturing development went the building up of an
elaborate procurement force charged with the responsibility of providing
parts to be assembled at the Gas Defense Plant and at the Hero
Manufacturing Company. This Section faced a hard and intricate task, but,
though there were instances where the shortage of parts temporarily caused
a slowing down of production, these were remarkably rare. Not only had
the parts to be standardized, and specifications written, but a field
inspection force had to be trained in order that the finished parts might be
suitable for the final assembly plant. The problem was further complicated
by the fact that the design was constantly changing, as improvement
followed improvement. Officers, trained in inspection in a day, were sent
out to train inspectors in the industrial centers.
In February, 1918, shortly before the German drive commenced,
requisitions were received for sample lots of oiled mittens and oiled union
suits as protection against mustard gas. These were prepared in quantity and
sent to the front, as was also a considerable amount of chloride of lime for
neutralizing the mustard gas in the field.
Another phase of the work consisted of the Field Testing Section, which
was organized to provide field testing conditions for the regular product and
for the development organization. Later there were added a preliminary
course of training for officers for overseas duty in chemical warfare, the
military training of the Gas Defense officers located in and near New York
and the training of boat crews engaged in carrying offensive gas supplies.
The Field Testing Section rendered valuable service in pointing out
weaknesses of designs as developments took place and especially those
uncomfortable features of the masks which were apparent only through
long wear. During the course of this work the section built a complete

trench system in the Pennsylvania Railroad yards with an elaborate dugout,
the equal of any of the famous German quarters on the Western front.
The chapters on Charcoal, Soda-Lime and the Gas Mask must be read in
this connection to gain an idea of the work carried out by this Division. It is
summed up in the statement that American soldiers were provided with
equipment which neutralized the best effects of German chemical
knowledge as evidenced by the offensive methods and materials employed.
The organization of the Gas Defense Division, as of Nov. 11, 1918, was
as follows:
Colonel Bradley Dewey Officer in Charge
Lieut. Col. A. L. Besse Asst. Officer in Charge
Major M. L. Emerson Administration Section
Major H. P. Schuit Comptrolling Section
Mr. R. Skemp Procurement Section
Major C. R. Johnson Technical Director
Capt. K. Atterbury Field Testing Section
Major J. C. Woodruff Chemical Manufacturing and
Development
Mr. R. R. Richardson Manager, Gas Defense Plant
Capt. H. P. Scott Officer in Charge,
Hero Manufacturing Co.
Major L. W. Cottman Engineering Branch
Major T. L. Wheeler Chemical Development
Major I. W. Wilson Astoria Branch
Capt. W. E. Brophy San Francisco Branch
Lt. E. J. Noble Cleveland Branch
Lt. L. Merrill Springfield Branch

Edgewood Arsenal

The Ordnance Department, in making plans for a shell filling plant,
thought to interest existing chemical firms in the manufacture of the
required toxic materials. As plans developed, however, difficulties arose in
carrying out this program. The manufacture of such material at private
plants necessitated its shipment to the filling plant at Edgewood. The
transportation of large quantities of highly toxic gases seemed attended with

great danger. The Director General of Railroads ruled that all such
shipments must be made by special train, a very expensive method of
transportation. Still more serious objections were encountered in the
attempt to enlist the co-operation of existing firms. They recognized that the
manufacture of such material would be attended by very great danger; that
the work would be limited to the duration of the war; and that the processes
involved, as well as the plants necessary for carrying out their processes,
would have little post-war value. Moreover, such firms as had the personnel
and equipment were already over-worked. With a few exceptions (notably
the American Synthetic Color Company, the Oldbury Electro-Chemical Co.,
Zinsser & Co., and the Dow Chemical Company) they were unwilling to
undertake work of this character on any terms whatever.
Early in December, 1917, therefore, it was decided to erect, on the site
of the shell filling plant, such chemical plants as would be necessary to
furnish the toxic materials required for filling the shell. The Arsenal is
situated in an isolated district, twenty miles east of Baltimore, Maryland, on
the Pennsylvania Railroad, and comprises 3,400 acres. Since the main line
of the Pennsylvania Railroad runs on one side of the tract, while on another
is the Bush River, only a few miles from its mouth in Chesapeake Bay, the
tract was ideally situated for shipping. This site was referred to, at first, as
“Gunpowder Reservation,” but on May 4, 1918, the name was officially
changed to “Edgewood Arsenal.”

Fig. 6.—Edgewood Arsenal.
The upper view shows the site as it appeared Oct. 24,
1917. The lower view shows the same as it appeared nine
months later.

Some idea of the extent of the work may be gained from the following
facts. On October 1, 1918, there were 233 officers, 6,948 enlisted men and
3,066 civilians engaged in work at Edgewood. 86 cantonments were built,
accommodating about 8,500 men, while the five officers’ barracks provided
accommodations for 290. The completed hospital unit consisted of 34
buildings, accommodating 420 patients under ordinary conditions. The total
number of buildings erected on the Arsenal grounds was 550. 14.8 miles of
improved roads were built, and 21 miles of standard gauge and 15 miles of
narrow gauge railway. A system furnishing 9.5 million gallons of salt water
and another furnishing two millions of fresh water daily were successfully
installed. Large power plants were built in connection with the shell filling
plants and the chlorine plant.
Plants for phosgene, chloropicrin, mustard gas, chlorine and sulfur
chloride were built and placed in successful operation. Most of the raw
materials, with the exception of sulfur chloride, were obtained from
commercial firms. The other gases and manufactured materials used, such
as phosphorus, tin and silicon tetrachlorides, bromobenzylcyanide and
arsenic derivatives were supplied by various plants scattered through the
East and Middle West States.

The raw materials used by the Arsenal in 1918 were as follows:
Salt 17,358,000 pounds
Bleach 42,384,000 “
Picric acid 3,718,000 “
Alcohol 3,718,000 “
Sulfur 24,912,000 “
Sulfur chloride 6,624,000 “
Bromine 238,000 “
Benzyl chloride 26,000 “
The production of toxic materials and the amount shipped overseas in
bulk follow:
Production, Shipped in Bulk,
Pounds Pounds
Chlorine:
Liquid 5,446,000 2,976,000
Gaseous 2,208,000
Chloropicrin 5,552,000 3,806,000
Phosgene 3,233,070 840,000
Mustard gas 1,422,000 380,000
Bromobenzyl cyanide 10,000
White phosphorus 2,012,000 342,000
Tin tetrachloride 2,012,000 212,000
Titanium tetrachloride 362,000

For nearly a month previous to the signing of the Armistice, the various
plants at the Arsenal had shut down or were operated only to an extent
sufficient to maintain the machinery and equipment in good working order,
on account of the lack of shell into which to fill the gas, so that the above
figures do not at all represent maximum productive capacity.
These plants will be described in the appropriate chapters.

The shell filling plant was really composed of several small plants, each
of which was made up of units radiating from a central refrigeration plant
which would serve all the units. Each unit could then be fitted with
machinery adapted for filling shell of a different size, and for a particular
gas. Moreover, an accident in one of the units would in no way impair the
working of the remainder.
The problem involved in the filling of a shell with toxic material (which
is always a liquid or a solid and never a gas under the conditions in which it
is loaded in the shell) is similar in a way to that of filling bottles with
carbonated water. In the development of plans for the filling plant, many
suggestions were obtained from a study of the apparatus used in
commercial bottling plants. It was necessary to keep in mind not only the
large number of shell to be filled, but also the highly toxic character of the
filling material to be used. It was essential that the work of filling and
closing the shell should be done by machinery in so far as that was possible,
and that the operation should be carried out in a thoroughly ventilated room
or tunnel, arranged so that the machinery contained in the tunnel could be
operated from the outside. Special care was taken in closing the shell, the
closing being accomplished by motors actuated by compressed air, which,
in the closing process were driven until they stalled. In this way a uniform
closing torque was obtained. The final results secured were admirable, as is
evidenced by the fact, reported by the Quartermaster Officer at Vincennes
on November 15, 1918, that not a single leaky shell had been found among
the 200,000 shell received up to that date.

Fig. 7.—A Typical Shell filling Plant at Edgewood Arsenal.

Details of the filling process will be found in the chapter on Phosgene.
Besides the ordinary gas filling plants (of which one was completed and
two were 80 per cent completed) there was a plant for stannic chloride
grenades, one for white phosphorus grenades, and one for smoke shell also
filled with phosphorus and a plant for filling incendiary bombs.
Shell are designated by their diameter in inches or millimeters. The
approximate amount of toxic gas required for filling each type of shell (10.5
per cent void) is as follows:
Phosgene, N. C.,[13] Mustard Gas,
Shell
Pounds Pounds Pounds
75 mm 1.32 1.75 1.35

Phosgene, N. C.,[13] Mustard Gas,
Shell
Pounds Pounds Pounds
4.7 inch 4.27 6.20 4.20
155 mm 11.00 15.40 10.35
8 inch 22.00 30.30 21.60
Livens 30.00
The gas grenades held 0.446 pound of stannic chloride, and the smoke
grenades held 0.67 pound of white phosphorus.
The only type of shell filled was the 75 mm. variety, because either the
shell of the other sizes or the accompanying boosters (bursting charges)
were not available.
The work done by the filling plant is shown by the following figures,
representing the number of shell, grenades, etc.
75 mm. Shell
Shipped
Filled
Overseas
Phosgene 2,009
N. C. 427,771 300,000
Mustard gas 155,025 150,000

Livens Drum
Phosgene 25,689 18,600

Grenades
White phosphorus 440,153 224,984
Tin tetrachloride 363,776 175,080

Incendiary Drop Bomb
Mark I. 542
Mark II. 2,104

The total monthly capacity of the filling plants at the date of the
Armistice was as follows:
Pounds
75 mm. shell 2,400,000
4.7 inch shell 450,000
155 mm. shell 540,000
6 inch shell 180,000
Gas grenade 750,000
Smoke grenade 480,000
Livens drum 30,000
One point relating to the casualties resulting from the work should
perhaps be mentioned here. The number of casualties should change the
mind of anyone who feels that men chose this work as being “safe” instead
of going to France. During the six months from June to December there
were 925 casualties, of which three were fatal, two being due to phosgene
and one to mustard gas. These were divided among the different gases as
follows:
Mustard gas 674
Stannic chloride 50
Phosgene 50
Chloropicrin 44
Chlorine 62
Other material 45
Of these 279 occurred during August, 197 during September and 293
during October. Since production stopped early in November, there were
only 14 during that month and three during December.
The Staff at Edgewood Arsenal at the signing of the Armistice was as
follows:
Commanding Officer Colonel Wm. H. Walker
Lt. Colonel George Cahoon, Jr.
Administrative Officers Lt. Col. Edward M. Ellicott
Lt. Col. Wm. C. Gallowhur

Lt. Col. Wm. McPherson
Major Adrian Nagelvoort
In Charge of Outside Plants
Major Charles R. Wraith
Captain John D. Rue
Shell Filling Plant Lt. Col. Edwin M. Chance
Chlorine Plant Lt. Col. Charles Vaughn
Chemical Plants Major Dana J. Demorest
Chemical Laboratory Major William L. Evans
As the work of the Arsenal expanded it was necessary to manufacture
certain of the chemicals at outside plants. The men in charge of these plants
were:
Bound Brook, N. J. Lt. William R. Chappell
Stamford, Conn. Lt. V. E. Fishburn
Hastings-on-Hudson, N. Y. Major F. G. Zinnsser
Niagara Falls, N. Y. Major A. Nagelvoort
Buffalo, N. Y. Lt. A. W. Davison
Kingsport, Tenn. Lt. E. M. Hayden
Charleston, W. Va. Lt. M. R. Hoyt
Midland, Mich. Major M. G. Donk
Croyland, Pa. Capt. A. S. Hulburt
After the Armistice, Edgewood Arsenal was selected as the logical
home of the Chemical Warfare Service, and all the outside activities of the
Service were gradually closed up and the physical property and files moved
to Edgewood. At first the command of the Arsenal was in the hands of Lt.
Col. Fries, but when he was appointed Chief of the Service, Major E. J.
Atkisson, who had so successfully commanded the First Gas Regiment, A.
E. F., was happily chosen his successor. At the present time (July 1, 1921),
the organization of Edgewood Arsenal is as follows:
Commanding Officer Major E. J. Atkisson
Executive Officer Major R. C. Ditto
Technical Director Dr. J. E. Mills
Chemical Division Mr. D. B. Bradner

Mechanical Division Mr. S. P. Johnson
Plant Division Capt. E. G. Thompson
Chemical Warfare School Major O. R. Meredith
Property Major A. M. Heritage
First Gas Regiment Major C. W. Mason
Mask Production Division Lt. L. A. Elliott
Medical Department Major T. L. Gore
Pathological Division Lt. H. A. Kuhn
Quartermaster Department Capt. H. L. Hudson
Finance Department Capt. C. R. Insley

Development Division

The Development Division had its origin in the research laboratories of
the National Carbon Company and of the National Lamp Works of the
General Electric Company. Both of these companies knew charcoal, and
they were asked to produce a satisfactory absorbent charcoal. The success
of this undertaking will be seen in the chapter on Absorbents. After a short
time all the laboratory work was taken over by the National Carbon Co.,
while the developmental work was assigned to the National Lamp Works.
When the final organization of the Chemical Warfare Service took place,
the National Carbon Laboratory became part of the Research Division,
while the National Lamp Works became the Defense Section of the
Development Division.
The Development Division may be considered as having been
composed of the following sections:

1. Defense
2. Offense
3. Midland
4. Willoughby
5. Special Investigation.

The work of the Defense Section consisted of the development of a
charcoal suitable for use in gas masks, and its manufacture. While the

details will be given later, it may be mentioned here that three weeks after
the organization of the Section (April 28, 1917) the furnaces of the National
Carbon Company were turning out cedar charcoal, using a straight
distillation procedure. Cedar was selected from a large variety of materials
as giving the highest absorptive value against chlorine. But phosgene and
chloropicrin were also being used, and it was found that the cedar charcoal
was not effective against either. Proceeding on a definite hypothesis, fifty
materials were investigated to find the charcoal with the highest density.
Cocoanut hulls furnished the raw material, which yielded the most active
charcoal. By a process of air activation a charcoal was obtained which
possessed high absorptive power for such gases as chloropicrin and
phosgene. Later this air process was changed to one in which steam is used;
the cocoanut shell charcoal activated with steam was given the name
“Dorsite.”
Complete apparatus for this air process was installed at the plant of the
Astoria Light, Heat & Power Company, Long Island City, and the first
charcoal was prepared during September, 1917. This was followed by a
large amount of experimental work, relating to the raw material, the method
of activation, and the type of furnace used. Because of the shortage of
cocoanut hulls, it later became necessary to use a mixture of cocoanuts with
cohune nuts, apricot and peach pits, cherry pits and vegetable ivory.
Another substitute for cocoanut charcoal was found in a steam activated
product from high grade anthracite coal, called “Batchite.”
The Offense Section and the Midland Section were concerned with the
manufacture of mustard gas. This work was greatly delayed because of the
unsatisfactory nature of the so-called chlorohydrin process. Another
difficulty was the development of a satisfactory ethylene furnace. Finally in
February, 1918, Pope in England discovered the sulfur chloride method of
making mustard gas. At once all the energies of the Research Division were
concentrated on this process, and in March steps were taken to put this
process into production. An experimental plant was established at
Cleveland; no attempt was made to manufacture mustard gas on a large
scale, but the results obtained in the experimental studies were immediately
transmitted to the manufacturing plants at Edgewood Arsenal, the Hastings-
on-Hudson plant, the National Aniline & Chemical Company (Buffalo)

plant, and the Dow Chemical Company (Midland) plant. The details of the
work on mustard gas will be given in a later chapter.
Special investigations were undertaken to develop a booster casing and
adapter for 75 mm. gas shell, and to duplicate the French process of lining
gas shell with glass.
The organization of the Development Division at the signing of the
Armistice was as follows:
Colonel F. M. Dorsey Chief of the Division
Major L. J. Willien Supt., Offense Section
Capt. O. L. Barnebey Supt., Defense Section
Lt. Col. W. G. Wilcox Supt., Experimental Station
Capt. Duncan MacRae Special Investigation Section
Dr. A. W. Smith Midland Section
Capt. J. R. Duff Administrative Section

Proving Division

The Proving Division had its origin in the decision to build an
Experimental Ground for gas warfare under the direction of the Trench
Warfare Section of the Ordnance Department. While this decision was
reached about September, 1917, actual work on the final location
(Lakehurst, N. J.) was not started until March 26, 1918, and the
construction work was not completed until August 1, 1918. However, firing
trials were started on April 25, 1918, and in all 82 were carried out.
The Proving Division was created to do two things: To experiment with
gas shell before they reached the point where they could be manufactured
safely in large numbers for shipment overseas; and to prove gas shell,
presumably perfect and ready for shipment, to guard against any
mechanical inaccuracies in manufacture or filling. It is evident that the
second proposition is dependent upon the first. Shell can not be proved to
ascertain the effect of gases under various conditions and concentrations
until the mechanical details of the shell itself, purely an Ordnance matter,
have been standardized. Unfortunately many of the tests carried out had to
do with this very question of testing Ordnance.

For field concentration work two complete and separate lines of
trenches were used and also several impact grounds. The trenches were
built to simulate the trenches actually used in warfare. Each line of trench
contained several concrete shell-proof dugouts and was also equipped with
shelves into which boxes could be placed for holding the sample bottles. At
intervals of one yard throughout the trenches there were electrical
connections available for electrical sampling purposes. The various impact
grounds were used for cloud gas attacks, and experiments with mustard gas
or in many cases for static trials. The samples were collected by means of
an automatic sampling apparatus.
The work of the Division consisted in the first instance of determining
the proper bursting charge. While a great deal of this work had been carried
out in Europe, American gas shell were enough different to require that tests
be carried out on them. The importance of this work is obvious, since
phosgene, a substance with a low boiling point, would require a smaller
bursting charge to open the shell and allow the substance to vaporize than
would mustard gas, where the bursting charge must be not only sufficient to
fragment the shell but also to scatter the liquid so that it would be atomized
over the largest possible area. In the case of low boiling liquids it was
necessary that the charge be worked out very carefully as a difference of
one or two grams would seriously affect the concentration. Too small a
charge would allow a cup to be formed by the base of the shell which would
carry some of the liquid into the ground, while too great an amount of
explosive tended to throw the gas too high into the air.
After the bursting charge had been determined a large number of shell
were repeatedly fired into the trenches, wooded areas, rolling and level
ground, and the concentration of gas produced and the effect upon animals
placed within the area ascertained. From the results of these experiments
the Proving Division was able to furnish the artillery with data regarding
how many shell of given caliber should be used, with corrections for
ranges, wind velocities, temperatures, ground conditions, etc. Trials were
also held to determine how many high explosive (H.E.) shell could be fired
with gas shell on the same area without unduly affecting the concentration.
This was important, because H.E. shell were useful in disguising gas
bombardments. Gas shell can usually be distinguished by the small
detonation on bursting.

Experiments were performed to determine the decomposition of various
gases on detonation. The shell were fired at a large wooden screen and burst
on impact. Samples of gas were taken immediately and analyzed.
Co-operative tests were carried out with the Gas Defense Division to
determine the value of given masks under field conditions. Companies of
infantry, fully equipped for the field, would wear masks for hours at a time
digging trenches, cutting timber, drilling, etc., and imitating in every way,
as far as possible, actual field conditions. During these activities tons of gas
in cylinders were released in such a way that the men were enveloped in a
far higher concentration than would probably ever be the case in actual
battle. These tests gave valuable data for criticizing gas mask construction.
Another line of activity consisted of a study of the persistency and
relative effectiveness of various samples of mustard gas, in which the liquid
was distributed uniformly upon the surface of grassy zones one to three feet
in width, which formed the periphery of circular areas 14 to 21 feet in
diameter, the central part of each circle being occupied by animals.
The work of the Proving Division was brought to an end (by the
Armistice) just at the time when it had reached its greatest usefulness. Not
only were the physical properties and personnel of the Division developed
to the maximum degree, but the production of gas shell in this country for
shipment to France had just reached the stage where the Proving Ground
could have been used to its fullest extent in their proving.

Training Division

From the standpoint of the man at the front the Training Division is one
of the most important. To him gas warfare is an ever present titanic struggle
between poisonous vapors that kill on one side, and the gas mask and a
knowledge of how and when to wear it, on the other. Because of this it is
rather surprising that we did not hear more about this branch of the Service.
It did exist, however, and credit must be given to those camp gas officers
who remained in the United States performing an inconspicuous and
arduous duty in the face of many local obstacles.

Fig. 8.

The Field Training Division of the Gas Defense Service in the United
States was organized in September, 1917, and consisted of Major J. H.
Walton and 45 first lieutenants, all chemists. These men were given a three
months’ military training at the American University. The arrival of Major
(now Colonel) Auld during this time was very helpful, as he was able to
give the Section first-hand knowledge. About 12 of the 45 men wore sent to
France, while the remainder, together with British Gas Officers, were
assigned to various Divisions still in training. There was little idea at that
time as to what constituted real gas training. No one knew how much gas
training would be received in France, and since little was often received due
to lack of time, many men went into action with no idea of what this
training really meant. Moreover, an order that the gas officers should not go

to France with their Divisions had, as was only natural, a discouraging
effect upon the men and upon gas training and discipline generally.
In January, 1918, the gas officers were transferred to the Engineers, and
designated as the 473d Engineers. Later an Army Gas School was
established at Camp Humphreys. Because of the rapidly changing
personnel, owing to overseas assignments, the policy was adopted of
sending specialized gas officers only to Divisional Camps and the larger
training centers. The need of a larger unit and increased authority was
recognized by all intimately associated with the work, but little was
accomplished until the transfer to the Chemical Warfare Service. Upon the
appointment of Brigadier General H. C. Newcomer as Assistant Director of
the Chemical Warfare Service, he was placed in charge of all military
affairs of the Service, and the administrative officers of the Training Section
became his “military assistants.” A few weeks later the Training Section of
the Administration Division, C.W.S. was formed.
At this time new duties fell to the lot of this Section,
among the more important being:
(1) The organization of gas troops and casual
detachments for overseas duty;
(2) The establishment of a Chemical Warfare Training
Camp;
(3) The procurement and training of officers for
overseas duty.
For this purpose a training camp was established near the Proving
Ground (Camp Kendrick) to hold 1300 officers and men. Line officers were
sent from the larger camps for training, the best of whom might later be
transferred to the Chemical Warfare Service for duty as Gas Officers.
The work of the Section eventually grew to such proportions that it was
recognized as the Training Division of the Chemical Warfare Service. It
differed from other Divisions in that all administrative routine was carried
on through the offices of the Director, and with the assistance and co-
operation of its various Sections.
Because of the formation of the Chemical Warfare Service and the
apparent need for officers, the office was soon flooded with applications for

commissions. These were carefully examined and the men were sent first,
by courtesy of the Chief of Engineers, to Camp Humphreys for a month’s
course of military training. At the end of this period they were sent to Camp
Kendrick as students of the Army Gas School. Toward the last of October
all the officers and enlisted men were transferred to Camp Kendrick where
an Officers’ Training Battalion was organized.
It is obvious that the gas training of troops was the most responsible
duty of the Training Division. There was constantly in mind an ideal of
supervised and standardized training for all troops in the United States, and
the Division, at the time of the Armistice, for the first time found itself with
a nearly adequate corps of officers through whom this ideal could be
realized.

Medical Division

Dr. Yandell Henderson of Yale University was the logical man to
inaugurate the medical work of the Bureau of Mines, because of his
experience with oxygen rescue apparatus. A member of the first committee
of the Bureau, he secured, in July, 1917, an appropriation for the study of
toxic gases at Yale. This was in charge of Doctors Underhill, therapy;
Marshall, pharmacology; and Winternitz, pathology. When the American
University Station was opened Marshall was given charge of the
pharmacology. About the same time a factory protection unit was organized
under the direction of Doctors Bradley, Eyster and Loevenhart. At first this
committee reported to the Ordnance Department, but later the work was
transferred to the Gas Defense Service.
In December, 1917, the Medical Advisory Board was organized. This
included all the men who were carrying on experimental work of a medical
nature. This board had as its object the correlation of all medical work; new
work was outlined and attempts were made to secure the co-operation of
scientific men throughout the country. The following groups of workers
assisted in this effort: At Yale, Underhill studied therapy, turning his
animals over to Winternitz for pathological study. Henderson was specially
interested in the physiology of aviation. At the American University
Marshall carried on pharmacological research, specially as regards mustard
gas, the toxicology being covered by Loevenhart. A pathological laboratory

was also started, under Winternitz, where many valuable studies were made.
[14]
At Cleveland Sollmann was busy with mustard gas and protective
agents. Pearce, working in co-operation with Dr. Geer of the Goodrich
Rubber Company, perfected the Goodrich Lakeside Mask. His study was
very valuable as concerning the physiology of the gas mask. At Ann Arbor
Warthin and Weller[15] were studying the physiology and pathology of
mustard gas. Wells, Amberg, Helmholz and Austin of the Otho Sprague
Memorial Institute were interested in protective clothing, while at Madison,
Eyster, Loevenhart and Meek were engaged in a study of the chronic effect
of long exposures to low concentrations, and later expanded their work to
protective ointments and certain problems in pathology.
In the spring of 1918 many of these men were commissioned into the
Gas Defense Service of the Sanitary Corps, and were later transferred to the
Chemical Warfare Service as the Medical Division, with Colonel W. J.
Lyster, M.C., in charge.
One of the most important functions of this Division was the daily
testing of a large number of compounds for toxicity, lachrymatory or
vesicant properties. The accuracy of these tests might and probably did save
a large amount of unnecessary experimental work on the part of the
Research Division. These tests are described in a later chapter.
Very interesting and likewise valuable was the study of mustard gas by
Marshall, Lynch and Smith. They were able to work out the mechanism of
its action and the varying degrees of susceptibility in individuals (see page
171).
Another interesting point was the fact that in the case of certain gases
there is a cumulative effect. With superpalite and mustard gas the lethal
concentration (that concentration which is fatal after a given exposure) is
lower on longer exposures. On the other hand there is no cumulative effect
with hydrocyanic acid. Whether the action is cumulative or not depends on
the rate at which the system destroys or eliminates the poison.

Liaison Officers

This chapter should not be closed without reference to the Liaison
Service that was established between the United States and her Allies,

especially England.
During the early days no one in the States was familiar with the details
of gas warfare. At the request of the Medical Corps, upon the urgent
representations of the Gas Service, A.E.F., Captain (now Major) H. W.
Dudley was sent to this country (Sept., 1917) to assist in the development
and manufacture of gas masks. For some time he was the Court of Appeal
on nearly all technical points regarding matters of defense. Dudley’s
continual insistence on the need for maintaining the highest possible
standard of factory inspection was one of the factors resulting in the
excellent construction of the American Mask. In March, 1918, Lieut. Col.
Dewey and Captain Dudley made a trip to England and France, during
which the idea of a liaison between the defense organizations of the two
countries originated. Dudley was transferred to the Engineers, promoted
and placed in charge of the Liaison service. While the time until the
Armistice was too short to really test the idea, enough was accomplished to
show the extreme desirability of some such arrangement.
Probably the best known liaison officer from the British was Colonel S.
J. M. Auld, also sent upon the urgent representations of the Gas Service,
A.E.F. He arrived in this country about the middle of October, 1917, in
charge of 28 officers and 28 non-commissioned officers, who were to act as
advisers in training and many other military subjects besides gas warfare.
Since Auld had had personal experience with gas warfare as then practiced
at the front, his advice was welcomed most heartily by all the different
branches of the Army then handling gas warfare. On questions of general
policy Auld was practically the sole foreign adviser. The matter of gas
training was transferred from the Medical Corps to the Engineers, and was
greatly assisted by four pamphlets on Gas Warfare issued by the War
College, which were prepared by Major Auld with the assistance of Captain
Walton and Lieut. Bohnson. Later Auld gave the American public a very
clear idea of gas warfare in his series of articles appearing in the Saturday
Evening Post, and re-written as “Gas and Flame.”
Major H. R. LeSueur, who was at Porton previous to his arrival in this
country in December, 1917, rendered valuable aid in establishing the
Experimental Proving Ground and in its later operations.

Towards the close of the war the British War Office had drawn up a
scheme for a Gas Mission, which was to correlate all the gas activities of
England and America. This was never carried through because of the
signing of the Armistice.
The French representatives, M. Grignard, Capt. Hanker and Lt. Engel
furnished valuable information as to French methods, but they were
handicapped by the fact that French manufacturers did not disclose their
trade secrets even to their own Government.
About August, 1918, Lieut. Col. James F. Norris opened an office in
London. His duties were to establish cordial and intimate relations not only
with the various agencies of the British Government which were connected
with gas warfare, but also with the various laboratories where experiments
were being conducted, that important changes might be transmitted to
America with the least possible delay. The English made Colonel Norris a
member of the British Chemical Warfare Committee. Here again the signing
of the Armistice prevented a full realization of the importance of this work.

CHAPTER IV
THE CHEMICAL WARFARE SERVICE
IN FRANCE
It is worth noting here that the Chemical Warfare Service was organized
as a separate service in the American Expeditionary Forces nearly ten
months before it was organized in the United States, and that the
organization in the United States as heretofore described was patterned
closely on that found so successful in France.
Very soon after the United States declared war against the Central
Powers, a commission was sent abroad to study the various phases of
warfare as carried on by the Allies, and as far as possible by the enemy.
Certain members of this commission gave attention to chemical warfare.
One of those who did this was Professor Hulett of Princeton University. He,
with certain General Staff officers, gathered what information they could in
England and France concerning the gases used and methods of
manufacturing them, and to a very slight extent the methods of projecting
those gases upon the enemy. Some attention was paid to gas masks, but
there being nobody on the General Staff, or anywhere else in the Regular
Army, whose duty it was to look out particularly for chemical warfare
materials, these studies produced no results.
As has already been stated, the Medical Department started the
manufacture of masks, and the Bureau of Mines, under the leadership of the
Director, Mr. Manning, began studies upon poisonous gases and the
methods of manufacturing them just before or shortly after war was
declared.
Nevertheless, although American troops left for France in May, 1917, it
was not until the end of August—the 17th to be exact—that definite action
was taken toward establishing a Chemical Warfare Service, or, as it was
then known, a Gas Service in the American Expeditionary Forces. On that
date a cablegram was sent to the United States to the effect that it was
desired to make Lieut. Col. Amos A. Fries, Corps of Engineers, Chief of the

Gas Service, and requesting that no assignments to the regiment of gas
troops authorized in the United States be made which would conflict with
this appointment. On August 22d, Lieut. Col. Fries entered upon his duties
as Chief of the Gas Service.
There were then in France about 30 miles from the German lines, some
12,000 American troops without any gas masks or training whatever in
Chemical Warfare. Immediate steps were taken to teach the wearing of the
masks, and English and French gas masks were obtained for them at the
earliest possible moment. At the same time efforts were made to obtain
officer personnel for the C. W. S., and to have sent to France a laboratory
for making such emergency researches, experiments, and testing as might
become necessary. From that time to the end of the war the C. W. S.
continued to develop on broad lines covering research, development, and
manufacture; the filling of shell and other containers with poisonous gases,
smoke and incendiary materials; the purchase of gas masks and other
protective devices, as well as the handling and supply of these materials in
the field; the training of the Army in chemical warfare methods, both in
offense and defense; and the organization, equipment and operation of
special gas troops.
This gave an ideal organization whereby research was linked with the
closest possible ties to the firing line, and where the necessities of the firing
line were brought home to the supply and manufacturing branches and to
the development and research elements of the Service instantly and with a
force that could not have been obtained in any other manner. The success of
the C. W. S. in the field and at home was due to this complete organization.
To the Commander-in-Chief, General Pershing, is due the credit for
authorizing this organization and for backing it up whenever occasion
demanded. Other details of this work will be considered under the
following heads: Administrative; Training; Chemical Warfare Troops;
Supply; Technical; Intelligence; and Medical.

Administrative Duties

The duties of administration covered those necessary for a general
control of research, of supply, of training, and the operation of special gas
troops. At first the Chief of the Gas Service comprised the whole of the

Service since he was without personnel, material, rules, regulations, or
anything else of a chemical warfare nature.
The experience in getting together this organization should be sufficient
to insure that the United States will never place on any other man’s
shoulders the burden of organizing a new and powerful service in the midst
of war, 4,000 miles from home, without precedent, material, or anything
else on which to base action. It is true the Americans had available the
experience of the English and the French, and it should be said to the credit
of both of these nations that they gave of their experience, their time, and
their material with the greatest freedom and willingness, but just as
Americans are Americans and were Americans in 1917, just so the methods
of the French and English or of the enemy were not entirely suitable to
American conditions.
If there is any one thing needed in the training of U. S. Army leaders of
today and for the future, it is vision—vision that can foresee the size of a
conflict and make preparations accordingly. We do not mean vision that will
order, as happened in some cases, ten times as much material as could
possibly be used by even 5,000,000 troops, but the sort of vision that could
foresee in the fall of 1917 that 2,000,000 men might be needed in France
and then make preparations to get materials there for those troops by the
time they arrived.
In order to cover the early formative period of the C. W. S. in France
and to show some of the difficulties encountered, the following running
account is given of some of the early happenings without regard to the
subdivisions under which they might properly be considered.
Assignment of Chief of the Gas Service. Sailing from the United
States on the 23d of July, 1917, Fries arrived in Paris on the morning of
August 14, 1917, and was immediately assigned the task of organizing a
highway service for the American Expeditionary Forces. Five days later and
before the highway order was issued, he was asked what he would think if
his orders were changed so as to make him Chief of the newly proposed
Gas Service. Being given one night to think it over he told the General Staff
he would undertake the work. The road work was immediately closed up
and on the 22d of August the organization of a Gas Service was actively
started.

At that time some information concerning gases and gas troops had
been gathered by Colonel Barber of the General Staff. Likewise, Colonel
(later Brigadier General) Hugh A. Drum had made a rough draft of an order
accompanied by a diagram for the establishment of the Gas Service. This
information was turned over to Fries who was told to complete the draft of
the order, together with an organization chart, for the action of the
Commander-in-Chief. After one and a half days had been put on this work
the draft and chart were considered in good enough shape to submit to
General Pershing, Commander-in-Chief.
First Trip to British Gas Headquarters. Noting that the proposed
organization provided for the handling of 4-inch Stokes’ mortars by gas
troops, General Pershing asked why this work could not be done by regular
trench mortar companies. He was told that gas operations were too
technical and dangerous to be intrusted to any but especially trained troops,
and that, furthermore, it was understood that 4-inch Stokes’ mortars were
used only by the British troops. General Pershing said, “You had better beat
it to the British Gas Headquarters in the field and settle definitely that and
certain other minor points.” Fries told him he was only too glad to do this,
and, having completed preparations, left on the morning of August 25th
with Colonel Church and Captain Boothby, both of the Medical
Department, for St. Omer, Headquarters of the British Gas Service in the
Field.
Colonel Church of the Medical Department had been in France nearly
one and a half years prior to the entry of the United States into the war, and
had taken sufficient interest in Gas Warfare to collect considerable
information and a number of documents from French sources bearing on the
defensive side of the subject. Captain Boothby had done the same with the
British, including a course in a British Gas Defense School. On this trip
they took up the defensive side with the British, while Fries took up the
offensive side of the Service. The latter included gases used, gas troops, and
ammunition and guns used in Gas Warfare by the Artillery and other
branches of the Service. The trip included a brief visit to the headquarters of
the First British Army in the vicinity of Lens, where the British Gas Service
had a large depot of offensive gas material.
Order Forming Service. Returning on the 28th of August the order,
together with a chart organizing the Service, was completed and submitted

to the General Staff. This was published as G. O. 31, September 3, 1917. As
a result of a study of the information submitted by Colonel Barber and
General Drum, together with his own observations of British organization
and work, Fries decided it was advisable to make the Service cover as
complete a scope as possible and to make the order very general, leaving
details to be worked out as time and experience permitted. This proved to
be a very wise decision, because the entire absence of gas knowledge
among Americans either in France or the United States made it necessary to
build from the bottom up and do it rapidly. At that time, and at all times
since, it was found utterly impossible to separate the defensive side from
the offensive side. Indeed, many of the worst troubles of the British with
their Gas Service throughout nearly the whole war arose from such a
division of duties in their Service. Thus, the development of masks must be
kept parallel with the development of gases and methods of discharging
them. Otherwise a new gas invented may penetrate existing masks and
preparations be carried far towards using it before the development of
masks are undertaken to care for the new gas. Obviously a gas which our
own masks will not take care of cannot be safely used by our own troops
until new masks are developed to protect against it.
American and British Masks. Just prior to Fries’s assignment as Chief
of the Gas Service twenty thousand American-made masks or box
respirators were received from the United States. Through the energy of
Captain Boothby several of these had been sent at once to the British for
test. The test showed that the granules in the canisters were entirely too soft,
the charcoal of poor quality, and more than all else, the fabric of the face
piece was so pervious to gases that chloropicrin became unbearable to the
eyes in less than a minute under the standard test used by the British. A
cable containing this information had been framed and sent to the United
States just prior to Fries’s appointment as Chief of the Service.
August 23d, the day after Fries took charge, it was decided to adopt the
British mask or box respirator as the principal mask and the French M-2 as
an emergency, both to be carried by the soldier, the French M-2, however,
to be used only when the British mask became lost or unfit for use. A
requisition for one hundred thousand of each was at once submitted and
very shortly approved by the General Staff.

Getting Gas Supplies. It should be stated here that inasmuch as no Gas
Service had been organized in the United States, no money appropriation
had been made for it, thereby making it necessary for the Gas Service to
obtain all its supplies through other departments ordinarily handling the
same or similar materials. Thus defensive supplies were obtained through
the Medical Department and offensive supplies through the Ordnance
Department, while other miscellaneous equipment was obtained through the
Engineer Department, the Quartermaster Department, or the Signal Corps.
This procedure proved exceedingly embarrassing, cumbersome and
inefficient. To begin with it was necessary to get some agreement between
the departments as to what each would supply. This was very difficult,
resulting in delays and consumption of time which was urgently needed on
other work.
Not only was there trouble in getting orders accepted and started on the
way but following them up became practically impossible. None of the
Departments furnishing the materials were especially interested in them nor
in many instances did they realize the vital nature of them. Accordingly in
order to get any action it was necessary to continually follow up all orders
and doing this through another department created friction and
misunderstanding. Officers of these departments took the attitude that the
whole question of obtaining supplies should be left to them, once the
requisition was turned in. This could not be done. The Chief of the Gas
Service was absolutely responsible for gas supplies, and he fully realized
that no excuses would be accepted, no matter who stood in the way. It was
necessary to get action. Finally the matter was settled, some six months
after the Service was organized, by giving the Chemical Warfare Service
the right of direct purchase.
Purchase of Offensive Gas Supplies. Realizing the difficulty that
would probably be encountered in getting supplies at all times from the
British and French, two requisitions for offensive gas supplies to be
purchased from the British were submitted on September 8th and 10th
respectively. It would seem proper to state here that investigation showed
the British gas organization to be far superior to the French. Indeed, the
latter practically had no organization.
Consequently it was determined to purchase complete equipment for
gas troops and for the defensive side of the service from the British and to

make no attempt to produce new materials, methods or equipment until
ample supplies of the standard equipment of the British were at hand or in
process of manufacture or delivery. This was another exceedingly wise
conclusion. No supplies of any kind were received from the United States
for the next eight months, and then only masks and certain defensive
supplies. Indeed, no cylinders, mortars, projectors or artillery shell
containing gas were received from the United States until just before the
Armistice, though gas had been available in the United States for months in
large quantities, over 3,600 tons having been shipped in one ton containers
to the English and French. The Ordnance material was what was lacking.
Obtaining Personnel. On September. 8, Colonel R. W. Crawford was
assigned to duty with the Gas Service. This matter of obtaining personnel
became immediately, and continued for almost a year to be, one of the most
serious difficulties facing the new Gas Service. The troubles here again
were the same as those in respect to supplies. None of the old departments
were especially interested in gas and hence none of them desired to let good
officers be transferred.
Officers were scarce in the early days in France in every department of
the Service, consequently a new department with no organization in the
United States and no precedents or opportunities for promotion made the
obtaining of officers almost a matter of impossibility. Further than this,
while the Engineer Department was at first supposed to furnish most of the
officer personnel, it failed to do so, apparently looking upon the Gas
Service as an unimportant matter when compared with the regular work of
the Engineers. It was necessary to make direct application to the Chief of
Staff to obtain Colonel Crawford and shortly thereafter to cable directly to
the United States for officers. A year later enough officers were obtained
but only after the organization of a separate Service in the United States.
Supplies for Gas Troops. Colonel Crawford was at once put in Charge
of all supplies for the Gas Service, including the location and construction
of separate depots for that Service. Prior to this the General Staff had
decided to have chemical supplies stored in depots separate from those of
other supplies on account of the poisonous nature of the gases which might
prove very annoying if leakage occurred near any other class of supplies.
Colonel Crawford took hold of this work with zeal and energy and so
conducted it as to relieve the Chief of the Gas Service of all anxiety in that

matter. As before stated, on the 10th of September a requisition for a very
large quantity of offensive supplies for gas troops was submitted to the
General Staff for approval. Inasmuch as this involved approximately 50,000
gas cylinders, 50,000 Liven’s drums, with at least 20,000 Liven’s projectors
and a large number of Stokes’ mortars and bombs, there was considerable
difficulty in getting it approved. Finally Colonel Malone of the Training
Section, who took an active interest in the Chemical Warfare Service, got it
approved. Then began the difficulty of getting the order placed and of
trying to expedite the filling of the order on time. These difficulties were
never overcome until after the entire purchase of supplies was, as
previously related, taken care of by the Gas Service.
First Inter-allied Gas Conference. The first inter-allied gas conference
was held in Paris on September 16th, and consisted of American, British,
French, Italian, and Belgian delegates. The conference busied itself mainly
with questions of the medical treatment of gassed cases and of defense
against gas.
Mustard Gas. The principal topic under consideration at this
conference was the effects of the new mustard gas first used at Ypres
against the British on the nights of the 11th and 12th of July, 1917. The
British suffered nearly 20,000 casualties from this gas during the first six
weeks of its use, and were so worried over it that the start of the attacks
carried out later in the fall of 1917 against Ypres were delayed several days.
The casualties were particularly heavy because the smell of the gas was
entirely new and not unpleasant and because of the delayed action of the
gas, whereby men got no indication of its seriousness until 4 to 8 hours after
exposure. For these reasons men simply took shelter from the bombardment
without putting on masks or taking other precautions. As a result of the
Paris conference a long cable was sent to the United States asking among
other things that immediate report be made on the possibilities of producing
ethylene chlorhydrin, one of the essentials in the manufacture of mustard
gas by the only method then known.
Within two weeks after this conference, there occurred an incident
which illustrates the very great danger in taking the views of any one man
unless certain that he is in a position to be posted on all sides of the
question under discussion. A high British official was asked what he had
heard in regard to the new mustard gas, and what and how it was

considered. He said with emphasis that the British had no further fear of it
since they had learned what it was and how to take care of themselves and
that it had ceased to be any longer a problem with them.
Fries, knowing what he did, was convinced that this did not represent
the attitude of the British authorities who knew what the gas was doing, and
the statement was not allowed to influence the American Gas Service in the
least. This was a very fortunate thing as events later proved. It should also
be added that a quite similar report was made by a French officer in regard
to mustard gas some time in the month of October. The French officer had
more reason for his attitude than the British officer as up to that time
mustard gas had not been largely used against the French. However, both
cases simply emphasize the danger of accepting the views of any man who
has seen but one angle of a problem so complicated as gas in war.

Training

Training in Gas Defense. In the latter part of October seventeen young
engineer officers, who had just arrived in France, were assigned to the Gas
Service and were promptly sent to British Gas Schools for training in mask
inspection, salvage and repair and in training men to wear masks and take
other necessary precautions against gas in the field. It was also necessary at
this time to establish gas training in the First Division, and Captain Boothby
was assigned to that work.

Fig. 9.—Destroying Mustard Gas on the Battle Field.

It is important to note that the Gas Service had to begin operations
immediately upon its organization although it had almost no facilities of
any kind to work with. At one and the same time it was necessary to decide
upon the kinds of masks to be used and then to obtain them; to decide upon
methods of training troops in gas defense and start at once to do it; to decide
upon gases to be used and manufactured in the United States and then
obtain and send the necessary data and finally to decide what weapons gas
troops were to use and to purchase those weapons, since none of them
existed in the United States. Worse still no one in the United States was
taking any interest in them.
New Mask. About November 1, Major Karl Connell of the Medical
Department, National Guard of New York, reported for duty in response to
a cablegram that had been sent asking for him by name. It was intended to
send him to a British School to learn the art of teaching gas defense.
However, learning after a short talk with him that he had been interested in

making masks for administering anæsthesia, there was at once turned over
to him samples of all the masks in use by both the Allies and the Germans,
with a view to getting his ideas for a new mask. Within two or three hours
he suggested a new mask having a metal face piece with sponge rubber
against the face and with a canister to be carried on the back of the head.
At that early date it was realized that a new mask must be invented
which would be far more comfortable and give better vision than the British
respirators adopted for use. Connell, thirty-six hours after reporting, had so
far developed his idea that he was sent to Paris to make the first model,
which he succeeded in doing in about three weeks. This first mask was
good enough to risk testing in a high concentration of chlorine and while it
leaked to some extent it indicated that the idea was sound. The problem
then was to perfect the mask and determine how it could be produced
commercially on the large scale necessary to equip an army.
Since the British at this time and practically throughout the war were
much ahead of the French in all phases of gas warfare, Connell was sent to
London. There he succeeded in getting additional models in such shape that
one of them was sent to the United States during the first few days of
January, 1918. Connell’s work and experiments were continued so
successfully that after a model had been submitted to the General Staff, as
well as to General Pershing himself, one thousand were ordered to be made
early in May with a view to an extensive field test preparatory to their
adoption for general use in the United States Army.
In this connection, during November, 1917, a letter was written to the
United States stating that while the Gas Service in France insisted on the
manufacture of British respirators exactly as the British were making them,
they desired to have experiments pushed on a more comfortable mask to
meet the future needs of the Army.
The following four principles were set down in that letter: (a) That the
mask must give protection and that experience had shown that suitable
protection could only be obtained by drawing the air through a box filled
with chemicals and charcoal. (b) That there must be clear vision and that
experience to date indicated that the Tissot method of bringing the inspired
air over the eyepieces was by far the best, (c) That the mask must be as
comfortable as compatible with reasonable protection, and that this meant

the mouthpiece and noseclip must be omitted. (d) That the mask must be as
nearly fool proof as it could be made. That is, it should be of quick and
accurate adjustment, in the dark or in the trenches, and be difficult to
disarrange or injure once in position.
Gas Training and Battle of Picardy Plains. On March 21, 1918, as is
known to everyone, the Germans began their great drive from Cambrai
across the Picardy Plains to Amiens. While the battle was expected it came
as a complete surprise so far as the tactics used, and the extent and force of
the attack, were concerned. Lieutenant Colonel G. N. Lewis, who had been
sent about March 1 to British Gas Schools, and had been assigned to one of
the schools run by the Canadians, was thus just on the edge of the attack.
This gave him an opportunity to actually observe some of that attack and to
learn from eye-witnesses a great deal more. The school, of course, was
abandoned hurriedly and the students ordered back to their stations. Lewis
submitted two brief reports covering facts bearing on the use of gas and
smoke by the Germans. These reports exhibited such a grasp of gas and
smoke battle tactics that he was immediately ordered to headquarters as
assistant on the Defense side of gas work, that is, on training in gas defense.
Up to that time no one had been able to organize the Defensive side of gas
work in the way it was felt it must be organized if it were to prove a
thorough success. A month later he was put at the head of the Gas Defense
Section, and in two months he had put the Defense Division on a sound
basis. He was then ordered to the United States to help organize Gas
Defense Training there.

Fig. 10.—Close Burst of a Gas Shell.
The 6th Marines in the Sommediene Sector
near Verdun, April 30, 1918.

Cabled Report on Picardy Battle. Based partly on Colonel Lewis’s
written and oral reports, and also on information contained in Intelligence
dispatches and the newspapers, a cablegram of more than 300 words was
drafted reciting the main features of the battle so far as they pertained to the
use of gas. This cablegram ended with the statement that “the above
illustrates the tremendous importance of comfort in a mask” and that “the
future mask must omit the mouthpiece and noseclip.”
Keeping the General Staff Informed of Work. In the early part of
May, 1918, the Americans arrived in the vicinity of Montdidier, south of
Amiens, on the most threatened point of the western front. It was on May
18, 1918, that the Americans attacked, took, and held against several
counter-attacks the town of Cantigny. Shortly afterward they were very
heavily shelled with mustard gas and suffered in one night nearly 900
casualties. Investigation showed that these casualties were due to a number

of causes more or less usual, but also to the fact that the men had to wear
the mask 12 to 15 hours if they were to escape being gassed. Such long
wearing of the British mask with its mouthpiece and noseclip is practically
an impossibility and scores became gassed simply through exhaustion and
inability to wear the mask.
An inspector from General Headquarters in reporting on supplies and
equipment in the First Division, stated that one of the most urgent needs
was a more comfortable mask. The First Division suggested a mask on the
principles of the new French mask which was then becoming known and
which omitted the mouthpiece and noseclip. The efforts of the American
Gas Service in France to perfect a mask without a mouthpiece and noseclip
were so well known and so much appreciated that they did not even call
upon the Gas Service for remark. The assistant to the Chief of Staff who
drew up the memorandum to the Chief simply said the matter was being
attended to by the Gas Service. This illustrates the value of keeping the
General Staff thoroughly informed of what is being done to meet the needs
of the troops on the firing line.
Then, as always, it was urged that a reasonably good mask was far more
desirable than the delay necessary to get a more perfect one. Based on these
experiences with mask development, the authors are convinced that the
whole tendency of workers in general, in laboratories far from the front, is
to over-estimate the value of perfect protection based on laboratory
standards. It is difficult for laboratory workers to realize that battle
conditions always require a compromise between perfection and getting
something in time for the battle. It was early evident to the Gas Service in
France that we were losing, and would continue to lose, vastly more men
through removal of masks of the British type, due to discomfort and
exhaustion, than we would from a more comfortable but less perfect mask.
In other words when protection becomes so much of a burden that the
average man cannot or will not stand it, it is high time to find out what men
will stand, and then supply it even at the expense of occasional casualties.
Protection in battle is always relative. The only perfect protection is to stay
at home on the farm. The man who cannot balance protection against
legitimate risks has no business passing on arms, equipment or tactics to be
used at the Front.

As early as September, 1917, gas training was begun in the First
Division at Condrecourt. This training school became the First Corps
School. Later a school was established at Langres known as the Army Gas
School while two others known as the Second and Third Corps Gas Schools
were established elsewhere. The first program of training for troops in
France provided for a total period of three months. Of this, two days were
allowed the Gas Service. Later this was reduced to six hours,
notwithstanding a vigorous protest by the Gas Service. However, following
the first gas attacks against the Americans with German projectors in
March, 1918, followed a little later by extensive attacks with mustard gas,
the A. E. F. Gas Defense School was established at the Experimental Field.
Arrangements were made for the accommodation of 200 officers for a six-
day course. The number instructed actually averaged about 150, due to the
feeling among Division Commanders that they could not spare quite so
many officers as were required to furnish 200 per week.
This school was conducted under the Commandant of Hanlon Field,
Lieutenant Colonel Hildebrand, by Captain Bush of the British Service.
This Gas Defense School became one of the most efficient schools in the A.
E. F., and was developing methods of teaching that were highly successful
in protecting troops in the field.
Failure of German Gas. The losses of the Americans from German gas
attacks fluctuated through rather wide limits. There were times in the early
days during training when this reached 65 per cent of the total casualties.
There were other times in battle, when due to extremely severe losses from
machine gun fire in attacks, that the proportion of gas losses to all other
forms of casualties was very small. On the whole the casualties from gas
reached 27.3 of all casualties. This small percentage was due solely to the
fact that when the Americans made their big attacks at San Mihiel and the
Argonne, the German supply of gas had run very low. This was particularly
true of the supply of mustard gas.

Fig. 11.—German Gas Alarms.

Fries was at the front visiting the Headquarters of the First Army and
the Headquarters of the 1st, 3d, and 5th Corps from two days before the
beginning of the battle of the Argonne to four days afterwards. He watched
reports of the battle on the morning of the attack at the Army Headquarters
and later at the 1st, 5th and 3d Corps headquarters in the order named. No
reports of any gas casualties were received. This situation continued
throughout the day. It was so remarkable that he told the Chief of Staff he
could attribute the German failure to use gas to only one of two possible
conditions; first, the enemy was out of gas; second, he was preparing some
master stroke. The first proved to be the case as examination after the
Armistice of German shell dumps captured during the advance revealed less
than 1 per cent of mustard gas shell. Even under these circumstances the

Germans caused quite a large number of gas casualties during the later
stages of the fighting in the Argonne-Meuse sector.
Evidently the Germans, immediately after the opening of the attack, or
more probably some days before, began to gather together all available
mustard gas and other gases along the entire western battle front, and ship
them to the American sector. This conclusion seems justified because the
enemy never had a better chance to use gas effectively than he did the first
three or four days of the Argonne fight, and knowing this fact he certainly
would never have failed to use the gas if it had been available. Had he
possessed 50 per cent of his artillery shell in the shape of mustard gas, our
losses in the Argonne-Meuse fight would have been at least 100,000 more
than it was. Indeed, it is more than possible we would never have succeeded
in taking Sedan and Mezieres in the fall of 1918.
Officers’ Training Camp. The first lot of about 100 officers were sent
to France in July, 1918, with only a few days’ training, and in some cases
with no training at all. Accordingly, arrangements were made to train these
men in the duties of the soldier in the ranks, and then as officers. Their
training in gas defense and offense followed a month of strenuous work
along the above mentioned lines.
This camp was established near Hanlon (Experimental) Field, at a little
town called Choignes. The work as laid out included squad and company
training for the ordinary soldier, each officer taking turns in commanding
the company at drill. They were given work in map reading as well as office
and company administration.
This little command was a model of cleanliness and military discipline,
and attracted most favorable comment from staff officers on duty at General
Headquarters less than two miles distant. Just before the Armistice
arrangements were made to transfer this work to Chignon, about 25 miles
southeast of Tours, where ample buildings and grounds were available to
carry out not alone training of officers but of soldiers along the various lines
of work they would encounter, from the handling of a squad, to being Chief
Gas Officer of a Division.
Educating the Army in the Use of Gas. As has been remarked before,
the Medical Department in starting the manufacture of gas masks and other
defensive appliances, and the Bureau of Mines in starting researches into

poisonous gases as well as defensive materials, were the only official bodies
who early interested themselves in gas warfare. Due to this early work of
the Bureau of Mines and the Medical Department in starting mask
manufacture as well as training in the wearing of gas masks, the defensive
side of gas warfare became known throughout the army very far in advance
of the offensive side. On the other hand, since the Ordnance Department,
which was at first charged with the manufacture of poisonous gases, made
practically no move for months, the offensive use of gas did not become
known among United States troops until after they landed in France.
Moreover, no gas shell was allowed to be fired by the artillery in
practice even in France, so that all the training in gas the artillery could get
until it went into the line was defensive, with lectures on the offensive.
The work of raising gas troops was not begun until the late fall of 1917
and as their work is highly technical and dangerous, they were not ready to
begin active work on the American front until June, 1918.
By that time the army was getting pretty well drilled in gas defense and
despite care in that respect were getting into a frame of mind almost hostile
to the use of gas by our own troops. Among certain staff officers, as well as
some commanders of fighting units, this hostility was outspoken and almost
violent.
Much the hardest, most trying and most skillful work required of
Chemical Warfare Service officers was to persuade such Staffs and
Commanders that gas was useful and get them to permit of a demonstration
on their front. Repeatedly Chemical Warfare Service officers on Division
staffs were told by officers in the field that they had nothing to do with gas
in offense, that they were simply defensive officers. And yet no one else
knew anything about the use of gas. Gradually, however, by constantly
keeping before the General Staff and others the results of gas attacks by the
Germans, by the British, by the French, and by ourselves, headway was
made toward getting our Armies to use gas effectively in offense.
But so slow was this work that it was necessary to train men particularly
how to appeal to officers and commanders on the subject. Indeed the
following phrase, used first by Colonel Mayo-Smith, became a watchword
throughout the Service in the latter part of the war—“Chemical Warfare
Service officers have got to go out and sell gas to the Army.” In other words

we had to adopt much the same means of making gas known that the
manufacturer of a new article adopts to make a thing manufactured by him
known to the public.

Fig. 12.—A Typical Shell Dump near the Front.

This work was exceedingly trying, requiring great skill, great patience
and above all a most thorough knowledge of the subject. As illustrating
some of these difficulties, the Assistant Chief of Staff, G-3 (Operations) of a
certain American Corps refused to consider a recommendation to use gas on
a certain point in the battle of the Argonne unless the gas officer would state
in writing that if the gas was so used it could not possibly result in the
casualty of a single American soldier. Such an attitude was perfectly absurd.
The Infantry always expects some losses from our own high explosive
when following a barrage, and though realizing the tremendous value of
gas, this staff officer refused to use it without an absolute guarantee in
writing that it could not possibly injure a single American soldier. Another

argument often used was that a gas attack brought retaliatory fire on the
front where the gas was used. Such objectors were narrow enough not to
realize that the mere fact of heavy retaliation indicated the success of the
gas on the enemy for everyone knows an enemy does not retaliate against a
thing which does not worry him.
But on the other hand, when the value of gas troops had become fully
known, the requests for them were so great that a single platoon had to be
assigned to brigades, and sometimes even to whole Divisions. Thus it fell to
the Lieutenants commanding these platoons to confer with Division
Commanders and Staffs, to recommend how, when and where to use gas,
and do so in a manner which would impress the Commanding General and
the Staff sufficiently to allow them to undertake the job. That no case of
failure has been reported is evidence of the splendid ability of these officers
on duty with the gas troops. Efficiency in the big American battles was
demanded to an extent unheard of in peace, and had any one of these
officers made a considerable failure, it certainly would have been reported
and Fries would have heard of it.
Equally hard, and in many cases even more so, was the work of the gas
officers on Division, Corps and Army Staffs, who handled the training in
Divisions, and who also were required to recommend the use of gas troops,
the use of gas in artillery shell and in grenades, and the use of smoke by the
infantry in attack. However, the success of the Chemical Warfare Service in
the field with these Staff officers was just as great as with the Regiment.
To the everlasting credit of those Staff Officers and the Officers of the
Gas Regiment from Colonel Atkisson down, both Staff Gas officers and
officers of the Gas Regiment worked together in the fullest harmony with
the single object of defeating the Germans.

Chemical Warfare Troops

Chemical Warfare troops were divided into two distinct divisions—gas
regiments and staff troops.

Fig. 13.—Firing a 155-Millimeter Howitzer.

The men are wearing gas masks to keep out the enemy gas fired at them
in Oct., 1918.]
Staff Troops. The staff troops of the Chemical Warfare Service
performed all work required of gas troops except that of actual fighting.
They handled all Chemical Warfare Service supplies from the time they
were unloaded from ships to the time they were issued to the fighting troops
at the front, whether the fighting troops were Chemical Warfare or any
other. They furnished men for clerical and other services with the Army,
Corps and Division Gas Officers, and they manufactured poisonous gases,
filled gas shells and did all repairing and altering of gas masks. Though
these men received none of the glamour or glory that goes with the fighting
men at the front, yet they performed services of the most vital kind and in
many cases did work as dangerous and hair raising as going over the top in
the face of bursting shell and screaming machine gun bullets.

Think of the intense interest these men must have felt when carrying
from the field of battle to the laboratory or experimental field, shell loaded
with strange and unheard of compounds and which might any moment burst
and end forever their existence! Or watch them drilling into a new shell
knowing not what powerful poison or explosive it might contain or what
might happen when the drill “went through”!
And again what determination it took to work 12 or 16 hours a day way
back at the depots repairing or altering masks, and, as was done at
Chateroux, alter and repair 15,000 masks a day and be so rushed that at
times they had a bare day’s work of remodeled masks ahead. But they kept
ahead and to the great glory of these men no American soldier ever had to
go to the front without a mask. And what finer work than that of these men
who, in the laboratory and testing room, toyed with death in testing
unknown gases with American and foreign masks even to the extent of
applying the gases to their own bodies.
Heroic, real American work, all of it and done in real American style as
part of the day’s work without thought of glory and without hope of reward.
The First Gas Regiment. In the first study of army organization made
by the General Staff it was decided to recommend raising under the Chief
of Engineers one regiment of six companies of gas troops.
Shortly after the cable of August 17, 1917, was sent stating that Lieut.
Colonel Fries would be made Chief of the Gas Service, the War Department
promoted him to be Colonel of the 30th Engineers which later became the
First Gas Regiment. At almost the same time, Captain Atkisson, Corps of
Engineers, was appointed Lieut. Col. of the Regiment. Although Colonel
Fries remained the nominal Commander of the regiment, he never acted in
that capacity, for his duties as Chief of the Gas Service left him neither time
nor opportunity. All the credit for raising, training, and equipping the First
Gas Regiment belongs to Colonel E. J. Atkisson and the officers picked by
him.
Immediately upon the formation of the Gas Service, the Chief urged that
many more than six companies of gas troops should be provided. These
recommendations were repeated and urged for the next two months or until
about the first of November, when it became apparent that an increase could
not be obtained at that time and that any further urging would only cause

irritation. The matter was therefore dropped until a more auspicious time
should arrive. This arrived the next spring when the first German projector
attack against United States troops produced severe casualties, exactly as
had been forecasted by the Gas Service. About the middle of March, 1918,
an increase from two battalions to six battalions (eighteen companies) was
authorized. A further increase to three regiments of six battalions each (a
total of fifty-four companies) was authorized early in September, 1918,
after the very great value of gas troops had been demonstrated in the fight
from the Marne to the Vesle in July.

Fig. 14.—Receiving and Transmitting Data
for Firing Gas Shell while Wearing Gas Masks.
Battlefield of the Argonne, October, 1918.

No Equipment for Gas Troops. About the first of December a
cablegram was received from the United States stating that due to lack of
equipment the various regiments of special engineers recently authorized,
including the 30th (Gas and Flame) would not be organized until the spring

of 1918. An urgent cablegram was then sent calling attention to the fact that
gas troops were not service of supply troops but first line fighting troops,
and consequently that they should be raised and trained in time to take the
field with the first Americans going into the line. At this same time the 30th
regiment was given early priority by the General Staff, A. E. F., on the
priority lists for troop shipments from the United States. The raising of the
first two companies was then continued under Colonel Atkisson at the
American University in Washington.
About January 15 word was received that the Headquarters of the
regiment and the Headquarters of the First Battalion together with
Companies A and B of the 30th Engineers (later the First Gas Regiment)
were expected to arrive very soon. Some months prior General Foulkes,
Chief of the British Gas Service in the field, had stated that he would be
glad to have the gas troops assigned to him for training. It was agreed that
the training should include operations in the front line for a time to enable
the American Gas Troops to carry on gas operations independently of
anyone else and with entire safety to themselves and the rest of the Army.
Due to the fact that the British were occupying their gas school, the
British General Headquarters were a little reluctant to take the American
troops Feb. 1. However, General Foulkes made room for the American
troops by moving his own troops out. He then placed his best officers in
charge of their training and at all times did everything in his power to help
the American Gas Troops learn the gas game and get sufficient supplies to
operate with. Colonel Hartley, Assistant to General Foulkes, also did
everything he could to help the American Gas Service. These two officers
did more than any other foreign officers in France to enable the Chemical
Warfare Service to make the success it did.
Second Battle of the Marne. The Chief of the Gas Service, following a
visit to the British Gas Headquarters, and the Headquarters of the American
2d Corps then operating with the British, arrived on the evening of July 17,
1918, at 1st Corps Headquarters at La Ferte sous Jouarre about 10 miles
southeast of Château-Thierry.
Two companies of the First Gas Regiment would have been ready in 48
hours to put off a projector attack against an excellent target just west of
Belleau Wood had not the 2d battle of the Marne opened when it did. It is

said that General Foch had kept this special attack so secret that the First
American Corps Commander knew it less than 48 hours prior to the hour
set for its beginning. Certainly the Chief of the Gas Service knew nothing
of it until about 9:00 p.m., the night of July 17th. Consequently the gas
attack was not made. At that time so little was known of the usefulness of
gas troops that they were started on road work. At Colonel Atkisson’s
suggestion that gas troops could clean out machine gun nests, he was asked
to visit the First Corps headquarters and take up his suggestion vigorously
with the First Corps Staff.
Attacking Machine Gun Nests. Thereupon the Gas troops were
allowed to try attacking machine gun nests with phosphorus and thermite.
This work proved so satisfactory that not long afterwards the General Staff
authorized an increase in gas troops from 18 companies to 54 companies, to
be formed into three regiments of two battalions each. The 6 companies in
France did excellent work with smoke and thermite during all the second
battle of the Marne to the Vesle river, where by means of smoke screens
they made possible the crossing of that river and the gaining of a foothold
on the north or German side.
With the assembling of American troops in the sector near Verdun in
September, 1918, the gas troops were all collected there with the exception
of one or two companies and took a very active part in the capture of the St.
Mihiel salient. It was at this battle that the Chemical Warfare Service really
began to handle offensive gas operations in the way they should be handled.
Plans were drawn for the use of gas and smoke by artillery and gas troops
both. The use of high explosives in Liven’s bombs was also planned. Those
plans were properly co-ordinated with all the other arms of the service in
making the attack. Gas was to be used not alone by gas troops but by the
artillery. Plans were made so that the different kinds of gases would be used
where they would do the most good. While these plans and their execution
were far from perfect, they marked a tremendous advance and demonstrated
to everyone the possibilities that lay in gas and smoke both with artillery
and with gas troops.
Following the attack on the St. Mihiel salient, came the battle of the
Argonne, where plans were drawn as before, using the added knowledge
gained at St. Mihiel. The work was accordingly more satisfactory. However,
the attempt to cover the entire American front of nine divisions with only

six companies proved too great a task. Practically all gas troops were put in
the front line the morning of the attack. Due to weather conditions they
used mostly phosphorus and thermite with 4 inch Stokes’ mortars. Having
learned how useful these were in taking machine gun nests, plans were
made to have them keep right up with the Infantry. This they did in a
remarkable manner considering the weight of the Stokes’ mortar and the
base plates and also that each Stokes’ mortar bomb weighed about 25
pounds. There were cases where they carried these mortars and bombs for
miles on their backs, while in other cases they used pack animals.

Fig. 15.—Setting Up a Smoke Barrage with Smoke Pots.

Not expecting the battle to be nearly continuous as it was for three
weeks, the men, as before stated, were all put in the front line the morning
of the attack. This resulted in their nearly complete exhaustion the first
week, since they fought or marched day and night during nearly the whole
time. Taking a lesson from this, in later attacks only half the men were put
in the line in the first place, no matter if certain sectors had to be omitted.
Fully as good results were obtained because, as the men became worn out,
fresh ones were sent in and the others given a chance to recuperate. Officers

relate many different occurrences showing the discipline and character of
these gas troops. On one occasion where a battalion of infantry was being
held up by a machine gun nest, volunteers were called for. Only two men,
both from the gas regiment, volunteered though they were joined a little
later by two others from the same regiment, and these four took the guns.
While it was not considered desirable for gas troops to attempt to take
prisoners, yet the regiment took quite a number, due solely to the fact that
they were not only with the advancing infantry but at times actually in front
of it. On another occasion a gas officer, seeing a machine gun battalion
badly shot up and more or less rattled, took command and got them into
action in fine shape.
At this stage the Second Army was formed to the southeast of Verdun
and plans were drawn for a big attack about November 14. The value of gas
troops was appreciated so much that the Second Army asked to have British
gas troops assigned to them since no American gas troops were available.
Accordingly in response to a request made by the American General
Headquarters, the British sent 10 companies of their gas troops. These
reached the front just before the Armistice, and hence were unable to carry
out any attacks there.
This short history of the operations of the First Gas Regiment covers
only the high spots in its organization and work. It covers particularly its
early troubles, as those are felt to be the ones most important to have in
mind if ever it be necessary again to organize C. W. S. troops on an
extensive scale. The Regiment engaged in nearly 200 separate actions with
poisonous gases, smoke and high explosives, and took part in every big
battle from the second battle of the Marne to the end of the War. They were
the first American troops to train with the British, and were undoubtedly the
first American troops to take actual part in fighting the enemy as they aided
the British individually and as entire units in putting off gas attacks, in
February and March, 1918. It would be a long history itself to recite the
actions in which the First Gas Regiment took part and in which it won
distinction.[16]
No better summary of the work of this Regiment can be written than
that of Colonel Atkisson in the four concluding paragraphs of his official
report written just after the Armistice:

“The First Gas Regiment was made up largely of
volunteers—volunteers for this special service. Little was
known of its character when the first information was
sent broadcast over the United States, bringing it to the
attention of the men of our country. The keynote of this
information was a desire for keen, red-blooded men who
wanted to fight. They came into it in the spirit of a
fighting unit, and were ready, not only to develop, but to
make a new service. No effort was spared to make the
organization as useful as the strength of the limited
personnel allowed.
“The first unit to arrive in France moved to the
forward area within eight weeks of its arrival, and, from
that time, with the exception of four weeks, was
continuously in forward areas carrying on operations. The
third and last unit moved forward within six weeks of its
arrival in France, and was continuously engaged until the
signing of the Armistice.
“That the regiment entered the fight and carried the
methods developed into execution where they would be
of value, is witnessed by the fact that over thirty-five
percent of the strength of the unit became casualties.
“It is only fitting to record the spirit and true devotion
which prompted the officers and men who came from
civil life into this Regiment, mastered the details of this
new service, and, through their untiring efforts and utter
disregard of self, made possible any success which the
Regiment may have had. It was truly in keeping with the
high ideals which have prompted our entire Army and
Country in this conflict. They made the motto of
‘Service,’ a real, living, inspiring thing.”

Supply

As previously stated it was decided early that the Chemical Warfare
Service should have a complete supply service including purchase,

manufacture, storage and issue, and accordingly separate supply depots
were picked out for the Gas Service early in the fall by Col. Crawford.
Where practicable these were located in the same area as all other depots
though in one instance the French forced the Gas Service to locate its gas
shell and bomb depot some fifteen miles from the general depots through an
unreasonable fear of the gas.
Manufacture of Gases. Due to the time required and the cost of
manufacturing gases, an early decision became imperative as to what gases
should be used by the Americans, and into what shells and bombs they
should be filled. As there was no one else working on the subject the sole
responsibility fell upon the Chief of the Gas Service. The work was further
complicated by the fact that the British and French did not agree upon what
gases should be used. The British condemned viciously Vincennite
(hydrocyanic acid gas with some added ingredients) of the French, while
the French stated that chloropicrin, used by the British principally as a
lachrymator, was worthless. Fries felt the tremendous responsibility that
rested upon him and finally after much thought and before coming to any
conclusion, wrote the first draft of a short paper on gas warfare. In that
paper he took up the tactical uses to which gases might be put and then
studied the best and most available gases to meet those tactical needs.
Without stating further details it was decided to recommend the
manufacture and use of chlorine, phosgene, chloropicrin, bromoacetone and
mustard gas. As the gas service was also charged with handling smoke and
incendiary materials, smoke was prescribed in the proportion of 5 per cent
of the total chemicals to be furnished. The smoke material decided upon
was white phosphorus.
The paper on Gas Warfare was then re-drafted and submitted to the
French and British and written up in final form prescribing the gases above
mentioned on October 26. Following this a cable was drawn and submitted
to the General Staff. After many conferences and some delay the cable went
forward on November 3.
Cable 268, November 4, 1917
Paragraph 12. For chief of Ordnance. With reference
to paragraph 2 my cablegram 181, desire prompt
information as to whether recommendation is approved

that phosgene, chloropicrin, hydrocyanic acid, and
chlorine be purchased in France or England and filling
plants established in France for filling shells and bombs
with those gases.
Subparagraph A. Reference to your telegram 253,
recommend filling approximately 10 per cent all shells
with gases as given below, but that filling plants and gas
factories be made capable of filling a total of 25 per cent.
Unless ordinary name is given, gases are designated by
numbers in chemical code War Gas investigations. Of 75
millimeter shells fill 1 per cent Vincennite, 4 per cent
phosgene or trichloromethyl chloroformate, 2 per cent
chloropicrin, 2½ per cent mustard gas, ½ per cent with
bromoacetone and ½ per cent with smoke material.
According to French 75 millimeter steel shells should not
be filled with Vincennite more than three months before
being used. No trouble with other gases or other sized
shells except that bromoacetone must be in glass lined
shells. Of 4.7 inch shells fill 5 per cent with phosgene or
trichloromethyl chloroformate, 2 per cent with
chloropicrin, 2½ per cent with mustard gas, ½ per cent
with bromoacetone and ½ per cent with smoke material.
Provide same percentage for all other shells up to and
including 8 inch caliber as for 4.7 inch shells. 4 inch
Stokes’ mortar will use same gases and smoke shells and
in addition thermit. 8 inch projector bombs will use the
same as the Stokes’ mortar and also oil to break into
flame on bursting. Cloud gas cylinders will be filled with
50 or 60 per cent phosgene, mixed with 40 to 50 per cent
chlorine, or phosgene and some other gas. Renew
recommendation that filling plants be established in
France to provide sudden shifts in gas warfare of all
kinds, as well as for filling all 4 inch Stokes’ mortar
bombs, 8 inch projector bombs and cloud gas cylinders. It
is strongly recommended that efforts be made to produce
white phosphorus on large scale for its usefulness both as
smoke screens and to produce casualties.

Subparagraph B. For the Adjutant General of the
Army. With reference to paragraph 2, my cablegram 181,
desire information as to whether recommendation is
approved that an engineer officer assisted by Professor
Hulett be assigned to Gas Service in Washington to
handle all orders and correspondence concerning gas.
Subparagraph C. For Surgeon General. With
reference to paragraph 2 your cablegram 205, and
paragraph 2, my cablegram 181, what is status of
chemical laboratory for France? Also have the 12
selected Reserve Officers for training in gas defense
sailed for France?
Subparagraph D. With reference to paragraph 17 your
cablegram 165 and paragraph 2 my cablegram 181, Tissot
has constructed simpler model of his mask for attachment
to any box. Have ordered 6 which will be completed in
two weeks, 3 of which will be forwarded at once. A
simple type such as this may prove useful for large
number of troops. Letter of permission to manufacture
Tissot masks being forwarded.
Subparagraph E. With reference to paragraph 8 your
cablegram 143, and paragraph 4 your cablegram 247, in
considering charcoal and other fillers for canister of box
respirator it should be remembered that the front is very
damp, the air being nearly saturated during greater part of
winter, fall and spring.

This cable is given in full to show that not later than November 4, 1917,
it was known in the United States not only what gases would be required
but also in what shells, bombs, guns and mortars each would be used. While
a small quantity of Vincennite was recommended in this cable, another
cable sent within a month requested that no Vincennite whatever be
manufactured. This decision as to gases and guns in which they were to be
used, while very progressive, proved entirely sound and remained
unchanged, with slight exceptions due to new discoveries, until the end of
the war. Without a thorough understanding of tactics a proper choice of

gases could not have been made. This fact emphasizes the necessity of
having a trained technical army man at the head of any gas service.
Due to the absence of a Chemical Warfare Service in the United States
at this time, a very great deal of the information sent from France, whether
by cable or by letter, never reached those needing it.
Smoke. About the first of December after a study of results obtained by
the British and the Germans in the use of smoke in artillery shells for
screening purposes, the Gas Service decided that much more smoke than
had been stated in cable 268 to the United States was desirable. The General
Staff, however, refused to authorize any increase, but did allow to be sent in
a cable a statement to the effect that a large increase in smoke materials
might be advisable for smoke screens, and that accordingly the amount of
phosphorus needed in a year of war would probably be three or four times
the one and a half million pounds of white phosphorus stated to have been
contracted for by the Ordnance Department in the United States. This
advanced position of the Gas Service in regard to smoke proved sound in
1918, when every effort was made to increase the quantity of white
phosphorus available and to extend its use in artillery shells including even
the 3 inch Stokes’ mortar.

Fig. 16.—Troops Advancing Behind a Smoke Barrage
(Phosphorus).

Overseas Repair Section No. 1. During the latter part of November,
1917, Overseas Repair Section No. 1, under the command of Captain
Mayo-Smith, Sanitary Corps, with four other officers and 130 men, arrived
in France. Since mask development and manufacture in the United States
was still under the Medical Department, this mask repair section was
organized as a part of the Sanitary Corps. As there were at that time no
masks to be repaired and no laboratory equipment or buildings for that
purpose on hand and none likely to be for months to come, Captain Mayo-
Smith was assigned to duty under Colonel Crawford, Chief Gas Officer
with the Line of Communication, in Paris. A site for a mask repair plant was
located at Châteauroux, and a site for a gas depot at Gievres was
investigated. Inasmuch as there was at that time greater need for men to
learn the handling of poisonous gases than to repair masks, some 40 or 50
of the company were put in gas shell filling plants at Aubervilliers and
Vincennes in the suburbs of Paris, while later still others were assigned to
Pont de Claix near Grenoble. The remainder of the company were used in
the Gas Depot at Gievres and in the office in Paris.

It was not until the latter part of June, 1918, that the mask repair plant
began operations. In the meantime these men did very valuable work in
shell filling and in learning the manufacture of gases. Several of them were
sent to the United States, some of them remaining throughout the war to aid
in gas manufacture and in shell filling.
Construction Division, Gas Service. The Construction Division under
Colonel Crawford in Paris made complete plans for phosgene
manufacturing plants, for shell filling plants and for the Mask Repair Plant.
These plans included a complete layout of the work for all persons to be
employed in the plants. During this same time a very careful study of the
possibilities for manufacturing gas for filling shell in France was made.
Finally about March 1, in accordance with the strong recommendations
of these men, Fries reported to General Pershing in person that the
manufacture of gas as well as the filling of shell in France was inadvisable
from every point of view and accordingly he recommended that gas
manufacture and shell filling in France be given up. General Pershing
strongly approved the recommendation and a cablegram was at once sent to
the United States to that effect. The main reason for this action was the lack
of chlorine, since chlorine was the principal ingredient of nearly all
poisonous gases then in use. Chlorine takes, besides salt, electric power and
lots of it. Electric power requires coal or water power. Neither of the latter
sources were available in France. This question was gone into very
thoroughly. The only place where power might have been developed was in
a remote spot near Spain, and the outlook there was such that it appeared
impossible to begin the manufacture of chlorine under two years. On the
other hand the shipment of chlorine from the United States required from
75 per cent to 100 per cent of the tonnage required to ship the manufactured
gases themselves, to say nothing of the labor, raw materials, and the
machinery that would have had to be shipped in order to manufacture gas in
France.
Mustard Gas. As previously stated Mustard Gas was first used by the
Germans against the British at Ypres on the nights of July 11 and 12, 1917.
It was not used much against the French until more than two months later.
Indeed, gas was never used by the Germans to the same extent against the
French as against the English. There are probably two reasons for this; first,
the Germans had a deeper hatred for the British than the French; second, the

British morale was higher than the French in 1917, and the German thought
that if he could break down this British morale, he could win the war.
The first attack came as a surprise and accordingly got an unusually
large number of casualties. As previously stated the casualties numbered
about 20,000 in about six weeks. This number was considered so serious
that the beginning of the series of attacks against Ypres in the fall of 1917,
was delayed by the British for 10 days or two weeks until they could study
better how to avoid such great losses from mustard gas. While the
composition of the gas was known within two or three days, as well as the
laboratory method by which it was first manufactured by Victor Meyer in
1886, it took some 11 months to develop reliable and practical methods of
manufacturing it on a large scale. The Inter-allied Gas Conference in
September, 1917, gave a great deal of attention to mustard gas and methods
of combating it both from the view point of prevention and of curing those
gassed by it.
Just following the close of that conference a cable was sent to the
United States asking the possibility of manufacturing ethylene chlorhydrin,
the principal element in the manufacture of mustard gas by the only process
then known. Later, that is about the middle of October, a cablegram was
sent urging investigation into the manufacture of this gas. It is believed a
great deal of time might have been saved had the policy of undue secrecy
not been adopted by the British and others before the Americans entered the
war. In fact we were only told in whispers the formula for mustard gas, and
where a description of it could be found in German chemistries. This was
arrant nonsense since if the Germans had gotten all mustard gas information
then in the hands of the British they would have received far less
information than they already possessed on mustard gas.

Fig. 17.—“Who Said Gas?”

Whether the information sent to the United States on mustard gas
ultimately proved of any great value is an open question since the methods
adopted in the United States were very greatly superior to those used in
England and in France. It probably helped by suggestion rather than by
actual details of design. Anyhow it all emphasizes the difficulties
encountered in war when so vital a substance as mustard gas must be
investigated after the enemy has begun using it on a large scale.
Delay of British Masks. As December 1 approached, and as nothing
further had been heard of the order for 300,000 British Respirators placed
about the middle of October, a telegram was sent to England asking if
deliveries would be made as required in the order for the masks. This order
required the first 75,000 to be delivered December 1, 1917. In reply it was
stated that the British could not furnish these masks, and that they
understood that the Americans were just beginning a large output of masks
in the United States. An exchange of cablegrams with the United States
showed that no masks could be expected from there for 3 to 5 months.
Moreover it became increasingly evident that the Americans were going

into the battle line sooner than at first contemplated. Another cablegram
was then sent to England urging the delivery of these masks. The reply was
to the effect that the English Government could not deliver the masks
because they did not have enough for their own use. This situation was very
serious. Unless the order for 300,000 masks placed with the British could
be filled, we were facing the necessity of sending American troops into the
front line with only the French M-2 mask. While the M-2 mask was then
the only mask used by the French, it was well known to afford practically
no protection against the high concentrations of phosgene obtained from
cloud or projector attacks. And it was just such attacks as these that our men
would encounter in the front line during training. Accordingly arrangements
were made for a hurried trip to England.
Colonel Harrison of the British Royal Engineers was in charge of the
British manufacture of masks and it is desired here to express appreciation
of his uniform courtesy and great helpfulness. He exhibited their methods
and facilities and assured us they could meet any requirements of ours for
masks up to a half million, or even more if necessary, provided they were
given time to establish additional facilities. Finally after a further exchange
of cables the masks were obtained.
During December, 1917 and January, 1918, when every effort was being
made to hurry a lot of masks from Havre—Havre being the British supply
base in France from which the masks were issued to the United States, the
severe cold and snow had so disorganized French traffic that it was
extremely difficult to get cars moving at all. In an effort to get the masks,
priority of shipment was obtained and two or three officers were assigned to
convoy the cars. Notwithstanding convoying, one carload of 4,000 masks,
mainly threes and fours, became lost and only turned up five weeks later. To
make matters worse the British were sending us very many more of the
small sized No. 2 masks than we could use. The loss of this carload of 4,000
number threes and fours was all but a tragedy. Indeed, in order to get the
First Brigade of the First Division equipped in time it was necessary to take
a large number of masks already issued to men of the Second Brigade.
These masks were first thoroughly washed and disinfected and then re-
issued.
This all emphasizes the great difficulties that are encountered when a
new and vital service must be organized in war 4,000 miles overseas

without material, home supplies, or men to draw from. This struggle to get
sufficient masks to keep all men fully equipped remained very acute until in
July, 1918, when the arrival of hundreds of thousands of masks from the
United States made the situation entirely safe. Even then the necessity of
weakening the elastics and shortening the rubber tubing of the mouthpieces
on some 700,000 masks, doubled up our work tremendously, and added
enormously to our troubles in getting masks to the front in time.
Notwithstanding these troubles the Chemical Warfare Supply Service
never failed and finally forged to the very forefront of all American supply
services. Its method of issuing supplies to troops at the front has been
adopted as the standard for American field armies of the future.

Technical

Gas Laboratory in Paris. Early in January, 1918, the first members of
the Chemical Service Section, National Army, under the command of
Colonel R. F. Bacon, arrived in France and reported for duty. Previously, a
laboratory site at Puteaux, a suburb of Paris, had been selected. This plant
had been built by a society for investigation into tuberculosis. Previous to
the arrival of the Chemical Service Section, information had been requested
from the United States by cable as to the size of the laboratory section to be
sent over. The reply stated that the number would probably total about 100
commissioned and enlisted. The site at Puteaux was accordingly definitely
decided upon. Just following this decision two cables, one after the other,
came from the United States recommending certain specified buildings in
Paris for the laboratory. It was found upon investigation in both cases that
the buildings were either absolutely unsuited or unfinished. This was
another case of trying to fight a war over 4,000 miles of cable. Colonel
Bacon was made head of the Technical Division, which position he held
throughout the war.

Fig. 18.—Shaper for Opening Captured Gas Shell.

Technically Trained Men. In January, 1918, in response to a cable
from the United States a request had been made on the French Government
to send six of their ablest glass blowers to the United States to aid in
making glass lined shells. The French Gas authorities said that it would be
impossible to send those or indeed any other men trained in the
manufacture or handling of poisonous gases or gas containers as they did
not have enough such men for their own work. Accordingly a cablegram
was drafted and sent to the United States, requesting that 50 men
experienced in various lines of technical and chemical work be sent to
France. The French authorities said they would put them in any factories,
laboratories or experimental places that the Chief of the Gas Service
desired. A second inquiry about these men was sent but nevertheless no
answer was ever received and no men were sent.
Protection Against Particulate Clouds. Just at this time, about the first
of February, 1918, the danger that the Germans might devise some better

method of sending over diphenylchloroarsine than by pulverizing it in high
explosive shell was felt to be serious. The British had just then perfected
protection against diphenylchloroarsine by employing unsized sulfate wood
pulp paper—48 to 60 layers being required. This number of layers was
found to be necessary as they are very thin and porous. The British had
developed a method of putting this paper around a canister and yet keeping
the canister small enough to fit into the knapsack by reversing its position
therein; that is, putting the canister in the compartment of the knapsack
made for the face piece and putting the face piece in the other compartment.
Some of our own officers and enlisted men were sent to England to work
with the British on this and an order given them for 200,000 of the
protected canisters. They improved on the methods of the British and as it
was found that sulfate paper was very scarce, investigations were made to
see if any of it could be manufactured in France. Very soon thereafter such a
place was located near the city of Nancy. Following this a cablegram was
sent to the United States giving complete specifications for making this
diphenylchloroarsine protection. From this cablegram successful samples
were made though somewhat more bulky than those developed in England.
Very few, however, of these were made in the United States due, we were
informed, to the poor quality of the sulfate paper. Work was however begun
energetically in the United States on other methods of protection against
diphenylchloroarsine.
Numbers of Chemists Needed. It was figured that out of a total force
of some 1,400 gas officers there would be needed in the A. E. F., exclusive
of those in regiments, approximately 200 chemists, i.e., about 15 per cent of
the whole. We arranged to have a good chemist on each Division, Corps and
Army Staff, and a certain number with the gas troops. It was proposed to
put 20 to 40 in the laboratory in Paris and not to exceed 20 at the
experimental field. This subject of personnel is touched on for the reason
that a few people seem to have the idea that the Chemical Warfare Service
should be made up of chemists exclusively. This is very far from being true.
It was and is believed that the Chemical Warfare Service should be
composed of men from every walk of life. In three positions out of every
four in the field a good personality combined with energy, hard work and
common sense count for more than mere technical training.

Hanlon (Experimental) Field. As early as December 15, 1917, it was
decided that an experimental field in France was necessary, and a letter was
written to the General Staff requesting authority to establish one. After
considerable delay the authority was granted and search for a site begun.
This was no easy task. While the French were loading millions of gas shells
at the edge of Paris, they appeared unwilling at first to have us establish a
gas experimental field except in abandoned or inaccessible spots. Finally a
very good site was found and agreed to by the French some 7 miles south of
General Headquarters. Just when we were ready to start work the French
discovered that the proposed field included a portion of one of their artillery
firing ranges. They then suggested another site within 3 miles of General
Headquarters. This was a rather fortunate accident as the site suggested was
a better one than at first picked out. The field was roughly rectangular from
7 to 8 miles in length, and 3 to 4 miles in width. The total area was about 20
square miles. The work of this experimental field proved a great success
and was rapidly becoming the real center of the Gas Service in France.
The old saying that the history of a happy country is very brief applies
to this story of the Technical Section of the Gas Service in France. Its work
did not begin as early as that of the other sections, and as considerable of it
was of a nature that could be put off without immediate fatal effects, the
Section was enabled to grow without the very serious drawbacks
encountered by other Sections of the Gas Service.
Nevertheless its usefulness was very great. Those of the Technical
Section either at the experimental field or at the laboratory were charged
with the opening of all sorts of known and unknown gas and high explosive
shells, fuses and similar things to determine their contents and their
poisonous or explosive qualities. This was work of a very technical nature,
and at the same time highly dangerous.
As stated elsewhere, the determination of the life of the masks became
one of the problems which the laboratory was trying to solve. Hundreds of
canisters were tested, and hundreds per month would have continued to
have been tested throughout the remainder of the war had the war gone into
1919. It was on the Technical Section that devolved the duty of determining
at the earliest possible moment the physical properties as well as the
physiological effects of any new gas.

Also on that Section fell the preliminary reports as to the probable
usefulness in war of a new gas whether sent over by the enemy or suggested
by our own Technical men, or those of our Allies. This was indeed a task by
itself, as it required a wide knowledge of the methods of using gases,
methods of manufacturing them, and methods of projecting them on the
field of battle.
In addition, it was the duty of the Technical Section to keep the Chief of
the Service fully informed on all the latest developments in gases and to get
that information in shape so that the Chief with his increasingly wide range
of duties would be enabled to keep track of them without reading the
enormous amount ordinarily written.
A much earlier start on technical work would have proved of immense
advantage. In case of another war, the technical side of chemical warfare
should be taken up with the very first expedition that proceeds to the hostile
zone. Had that been done in France, we would have had masks and gases
and proper shells and bombs at least six months before we did.

Intelligence

While Intelligence was for a long time under the Training or Technical
Divisions, it finally assumed such importance that it was made a separate
Division. It was so thoroughly organized that by the time of the Armistice
the Chief of the Division could go anywhere among the United States
forces down to companies and immediately locate the Gas Intelligence
officer.
Intelligence Division. This work was started by Lieutenant Colonel
Goss within a month after he reported in October, 1917. The Intelligence
Division developed the publication of numerous occasional pamphlets and
also a weekly gas bulletin. So extensive was the work of this Division that
three mimeograph machines were kept constantly going. The weekly
bulletin received very flattering notice from the British Assistant Chief of
Gas Service in the Field. He stated that it contained a great deal of
information he was unable to get from any other source.
Among other work undertaken by this Intelligence Division was the
compilation of a History of the Chemical Warfare Service in France. This

alone involved a lot of work. In order that this history might be truly
representative, about three months before the Armistice both moving and
still pictures were taken of actual battle conditions, as well as of numerous
works along the Service of Supplies.
Without going into further detail it is sufficient to say that when the
Armistice was signed there were available some 200 still pictures, and some
8,000 feet of moving picture films. Steps were immediately taken to have
this work continued along definite lines to give a complete and continuous
history of the Chemical Warfare Service in France in all its phases.
The intelligence work of the Gas Service, while parallel to a small
extent with the General Intelligence Service of the A. E. F., had to spread to
a far greater extent in order to get the technical details of research,
manufacture, development, proving, and handling poisonous gases in the
field. It included also obtaining information at the seats of Government of
the Allies, as well as from the enemy and other foreign sources.
The most conspicuous intelligence work done along these lines was by
Lieutenant Colonel J. E. Zanetti, who was made Chemical Warfare liaison
officer with the French in October, 1917. He gathered together and
forwarded through the Headquarters of the Chemical Warfare Service to the
United States more information concerning foreign gases, and foreign
methods of manufacturing and handling them, than was sent from all other
sources combined. By his personality, energy and industry he obtained the
complete confidence of the French and British. This confidence was of the
utmost importance in enabling him to get information which could have
been obtained in no other way. Suffice to say that in the 13 months he was
liaison officer with the French during the war, he prepared over 750 reports,
some of them very technical and of great length.
As a whole, the Intelligence Division was one of the most successful
parts of the Chemical Warfare Service. Starting 2½ years after the British
and French, the weekly bulletin and occasional papers sent out by the
Chemical Warfare Service on chemical warfare matters came to be looked
upon as the best available source for chemical warfare information, not
alone by our own troops but also by the British.

Medical

The Medical Section of the Chemical Warfare Service was composed of
officers of the Medical Department of the Army attached to the Chemical
Warfare Service. These were in addition to others who worked as an
integral part of the Chemical Warfare Service, either at the laboratory or on
the experimental field in carrying out experiments on animals to determine
the effectiveness of the gases.
The Medical Section was important for the reason that it formed the
connecting link between the Chemical Warfare Service and the Medical
Department. Through this Section, the Medical Department was enabled to
know the kinds of gases that would probably be handled, both by our own
troops and by the enemy, and their probable physiological effects.
Colonel H. L. Gilchrist, Medical Department, was the head of this
Section. It was through his efforts that the Medical Department realized in
time the size of the problem that it had to encounter in caring for gas
patients. Indeed, records of the war showed that out of 224,089 men,
exclusive of Marines, admitted to the hospitals in France, 70,552 were
suffering from gas alone. These men received a total of 266,112 wounds, of
which 88,980, or 33.4 per cent, were gas. Thus ⅓ of all wounds received by
men admitted to the hospital were gas. While the records show that the gas
cases did not remain on the average in the hospitals quite as long as in the
case of other classes of wounds, yet gas cases became one of the most
important features of the Medical Department’s work in the field.
The Medical Section, through its intimate knowledge of what was going
on in the Chemical Warfare Service as well as what was contemplated and
being experimented with, was enabled to work out methods of handling all
gas cases far in advance of what could have been done had there been no
such section. One instance alone illustrates this fully. It became known
fairly early that if a man who had been gassed with mustard gas could get a
thorough cleansing and an entire change of clothing within an hour after
exposure, the body burns could be eliminated or largely decreased in
severity. This led to the development of degassing units. These consisted of
1,200 gallon tanks on five-ton trucks equipped with a heater.
Accompanying this were sprinkling arrangements whereby a man could be
given a shower bath, his nose, eyes and ears treated with bicarbonate of
soda, and then be given an entire change of clothing. These proved a very

great success, although they were not developed in time to be used
extensively before the war closed.
There is an important side to the Medical Section during peace, that
must be kept in mind. The final decision as to whether a gas should be
manufactured on a large scale and used extensively on the field of battle
depends upon its physiological and morale effect upon troops. In the case of
the most powerful gases, the determination of the relative values of those
gases so far as their effects on human beings is concerned is a very
laborious and exacting job. Such gases have to be handled with extreme
caution, necessitating many experiments over long periods of time in order
to arrive at correct decisions.

CHAPTER V
CHLORINE
Chlorine is of interest in chemical warfare, not only because it was the
first poison gas used by the Germans, but also because of its extensive use
in the preparation of other war gases. The fact that, when Germany decided
upon her gas program, her chemists selected chlorine as the first substance
to be used, was the direct result of an analysis of the requirements of a
poison gas.
To be of value for this purpose, a chemical must satisfy at least the
following conditions:
(1) It must be highly toxic.
(2) It must be readily manufactured in large
quantities.
(3) It must be readily compressible to a liquid and
yet be more or less easily volatilized when the
pressure is released.
(4) It should have a considerably higher density
than that of air.
(5) It should be stable against moisture and other
chemicals.
Considering the properties of chlorine in the light of these requirements,
we find:
(1a) Chlorine is fairly toxic, though its lethal
concentration (2.5 milligrams per liter of air) is very high
when compared with some of the later gases developed.
This figure is the concentration necessary to kill a dog
after an exposure of thirty minutes. Its effects during the
first gas attack showed that, with no protection, the gas
was very effective.

(2a) Chlorine is very readily manufactured by the
electrolysis of a salt (sodium chloride) solution. The
operation is described below. In 100-pound cylinders, the
commercial product sold before the War for 5 cents a
pound. Therefore on a large scale, it can be manufactured
at a very much smaller figure.
(3a) Chlorine is easily liquefied at the ordinary
temperature by compression, a pressure of 16.5
atmospheres being required at 18° C. The liquid which is
formed boils at -33.6° C. at ordinary atmospheric
pressure, so that it readily vaporizes upon opening the
valve of the containing cylinder. Such rapid evaporation
inside would cause a considerable cooling of the cylinder,
but this is overcome by running the outlet pipe to the
bottom of the tank, so that evaporation takes place at the
end of the outlet pipe.
(4a) Chlorine is 2.5 times as heavy as air, and
therefore the gas is capable of traveling over a
considerable distance before it dissipates into the
atmosphere.
(5a) The only point in which chlorine does not seem
to be an ideal gas, is in the fact that it is a reactive
substance. This is best seen in the success of the primitive
protection adopted by both the British and the French
during the days immediately following the first gas
attack.
At first, however, chlorine proved a very effective weapon. During the
first six months of its use, its value was maintained by devising new
methods of attack. When these were exhausted, phosgene was added (see
next chapter). With the decline in importance of cloud gas attacks, and the
development of more deadly gases, chlorine was all but discarded as a true
war gas, but remained as a highly important ingredient in the manufacture
of other toxic gases.

Manufacture in the United States

It was at first thought that the existing plants might be able to supply the
government’s need of chlorine. The pre-war production averaged about 450
tons (900,000 pounds) per day. The greater amount of this was used in the
preparation of bleach, only about 60,000 pounds per day being liquefied.
Only a few of the plants were capable of even limited expansion. In an
attempt to conserve the supply, the paper mills agreed to use only half as
much bleach during the war, which arrangement added considerably to the
supply available for war purposes. It was soon recognized that even with
these accessions, large additions would have to be made to the chlorine
output of the country in order to meet the proposed toxic gas requirements.
After a careful consideration of all the factors, the most important of
which was the question of electrical energy, it was decided to build a
chlorine plant at Edgewood Arsenal, with a capacity of 100 tons (200,000
pounds) per day. The Nelson cell was selected for use in the proposed plant.
During the process of erection of the plant, the Warner-Klipstein Chemical
Company, which was operating the Nelson cell in its plant in Charleston,
West Virginia, agreed that men might be sent to their plant to acquire the
special knowledge required for operating such a plant. Thus when the plant
was ready for operation, trained men were at once available.

Fig. 19.—Chlorine Plant, Edgewood Arsenal.

Fig. 20.—Ground Plan of Chlorine Caustic Soda Plant,
Edgewood Arsenal.

The following description of the plant is taken from an article by S. M.
Green in Chemical and Metallurgical Engineering for July 1, 1919:
“The chlorine plant building, a ground plan of which is shown in Figure
20, consisted of a salt storage and treating building, two cell buildings, a
rotary converter building, etc. In connection with the chlorine plant, there
was also constructed a liquefying plant for chlorine and a sulfur chloride
manufacturing and distilling plant.
“The salt storage and treating building was located on ground much
below the cell buildings, which allowed the railroad to enter the brine
building on the top of the salt storage tanks. These tanks were constructed
of concrete. There were seven of these tanks, 34 feet long, 28 feet wide and
20 feet deep having a capacity for storing 4,000 tons of salt. There would
have been 200 tons of salt used per day when the plant was running at full
capacity.

“On the bottom of each tank distributing pipes for dissolving-water
supply were installed, and at the top of each, at the end next to the building,
there was an overflow trough and skimmer board arranged so that the
dissolving-water after flowing up through the salt, overflowed into this
trough and then into a piping system and into either of two collecting tanks.
The system was so arranged that, if the brine was not fully saturated, it
could be passed through another storage tank containing a deep body of
salt. The saturated brine was pumped from the collecting tanks to any one
of 24 treating tanks, each of which had a capacity of 72,000 gallons.
“The eighth storage bin was used for the storage of soda ash, used in
treating the saturated brine. This was delivered from the bin on the floor
level of the salt building to the soda ash dissolving tanks. From these tanks
it was pumped to any one of the 24 treating tanks. After the brine was
treated and settled, the clear saturated brine was drawn from the treating
tanks through decanting pipes and delivered by pumps to any one of the
four neutralizing tanks. These were located next to a platform on the level
of the car body. This was to provide easy handling of the hydrochloric acid,
which was purchased at first, though later prepared at the plant from
chlorine and hydrogen. The neutralized brine was delivered from the tanks
by a pump to a tank located at a height above the floor so that the brine
would flow by gravity to the cells in the cell building.
“There were to be two cell buildings, each 541 feet long by 82 feet
wide, and separated by partitions into four sections, containing six cell
circuits of 74 cell units. Each section is a complete unit in itself, provided
with separate gas pump, drying and cooling equipment, and has a
guaranteed capacity of 12.5 tons of chlorine gas per 24 hours.
“Each Nelson electrolytic cell unit consists of a complete fabricated
steel tank 13 by 32 by 80 inches, a perforated steel diaphragm spot welded
to supporting angle irons, plate glass dome, fourteen Acheson graphite
electrodes 2.5 inches in diameter, 12 inches long and fourteen pieces of
graphite 4 by 4 by 17 inches, and various accessories. (The cell is
completely described in Chemical and Metallurgical Engineering, August
1st, 1919.) Each cell is operated by a current of 340 amperes and 3.8 volts
and is guaranteed to produce 60 pounds of chlorine gas and 65 pounds of
caustic soda using not more than 120 pounds of salt per 24 hours, the gas to
be at least 95 per cent pure.

Fig. 21.—Interior View of the Cell Building.

“The salt solution from the cell feed tank, located in the salt treating
building, flows by gravity through a piping system located in a trench
running the length of each cell building, and is delivered to each cell unit
through an automatic feeding device which maintains a constant liquor
level in the cathode compartment.
“The remaining solution percolates from the cathode compartment
through the asbestos diaphragm into the anode compartment and flows from
the end of the cell, containing from 8 to 12 per cent caustic soda, admixed
with 14 to 16 per cent salt, into an open trough and into a pipe in the trench
and through this pipe by gravity to the weak caustic storage tanks located
near the caustic evaporator building.

Fig. 22.—Nelson Electrolytic Cell, showing the
Interior Arrangement of the Cell.

“The gas piping from the individual cell units to and including the
drying equipment is of chemical stoneware. The piping is so designed that
the gas can be drawn from the cells through the drying equipment at as near
atmospheric pressure as possible in order that the gas can be kept nearly
free of air. When operating, the suction at the pump was kept at ¹/₂₀ inch or
less. The quality of the gas was maintained at a purity of 98.5 to 99 per
cent. The coolers used were very effective, the gas being cooled to within
one degree of the temperature of the cooling water, no refrigeration being
necessary. The drying apparatus consisted of a stoneware tower of special
design containing a large number of plates, and thus giving a very large acid
exposure. There was practically no loss of vacuum through the drying tower
and cooler. The gas pumping equipment consisted of two hydroturbine
pumps using sulfuric acid as the compressing medium. The acid was cooled
by circulation through a double pipe cooler similar to those used in
refrigerating work. The gas was delivered under about five pounds pressure
into large receiving tanks located just outside the pump rooms, and from

these tanks into steel pipe mains which conducted the gas to the chemical
plant.”
The purity of the gas was such that it was not found necessary to liquefy
it for the preparation of phosgene.

Properties

Chlorine, at ordinary atmospheric pressure and temperature, is a
greenish yellow gas (giving rise to its name), which has a very irritating
effect upon the membranes of the nose and throat. As mentioned above, at a
pressure of 16.5 atmospheres at 18° C., chlorine is condensed to a liquid. If
the gas is first cooled to 0°, the pressure required for condensation is
decreased to 3.7 atmospheres. This yellow liquid has a boiling point of
-33.6° C. at the ordinary pressure. If very strongly cooled, chlorine will
form a pale yellow solid (at -102° C.). Chlorine is 2.5 times as heavy as air,
one liter weighing 3.22 grams. 215 volumes of chlorine gas will dissolve in
100 volumes of water at 20°. It is very slightly soluble in hot water or in a
concentrated solution of salt.
Chlorine is a very reactive substance and is found in combination in a
large number of compounds. Among the many reactions which have proved
important from the standpoint of chemical warfare, the following may be
mentioned:
Chlorine reacts with “hypo” (sodium thiosulfate) with the formation of
sodium chloride. Hypo is able to transform a large amount of chlorine, so
that it proved a very satisfactory impregnating agent for the early cloth
masks.
Water reacts with chlorine under certain conditions to form
hypochlorous acid, HOCl. In the presence of ethylene, this forms ethylene
chlorhydrin, which was the basis for the first method of preparing mustard
gas. In the later method, in which sulfur chloride was used, chlorine was
used in the manufacture of the chloride.
Chlorine reacts with carbon monoxide, in the sunlight, or in the
presence of a catalyst, to form phosgene, which is one of the most valuable
of the toxic gases.

Chlorine and acetone react to form chloroacetone, one of the early
lachrymators. The reaction of chlorine with toluene forms benzyl chloride,
an intermediate in the preparation of bromobenzylcyanide.
In a similar way, it is found that the greater number of toxic gases use
chlorine in one phase or another of their preparation. One author has
estimated that 95 per cent of all the gases used may be made directly or
indirectly by the use of chlorine.
Chlorine has been used in connection with ammonia and water vapor
for the production of smoke clouds. The ammonium chloride cloud thus
produced is one of the best for screening purposes. In combination with
silicon or titanium as the tetrachloride it has also been used extensively for
the same purpose.
On the other hand one may feel that, whatever bad reputation chlorine
may have incurred as a poison gas, it has made up for it through the
beneficial applications to which it has lent itself. Among these we may
mention the sterilization of water and of wounds.
In war, where stationary conditions prevail only in a small number of
cases, the use of liquid chlorine for sterilization of water is impractical. To
meet this condition, an ampoule filled with chlorine water of medium
concentration has been developed, which furnishes a good portable form of
chlorine as a sterilizing agent for relatively small quantities of water.
Chlorine has also been applied, in the form of hypochlorite, to the
sterilization of infected wounds. The preparation of the solution and the
technique of the operation were worked out by Dakin and Carrel. This
innovation in war surgery has decreased enormously the percentage of
deaths from infected wounds.

CHAPTER VI
PHOSGENE
The first cloud attack, in which pure chlorine was used, was very
effective, but only because the troops attacked with it were entirely
unprotected. Later, in spite of the varied methods of attack, the results were
less and less promising, due to the increased protection of the men and also
to the gas discipline which was gradually being developed. During this time
the Allies had started their gas attacks (Sept., 1915), and it soon became
evident that, if Germany was to keep her supremacy in gas warfare, new
gases or new tactics would have to be introduced.
The second poison gas was used in December, 1915, when about 20-25
per cent of phosgene was mixed with the chlorine. Here again the Germans
made use of an industry already established. Phosgene is used commercially
in the preparation of certain dyestuffs, especially methyl violet, and was
manufactured before and during the war by the Bayer Company and the
Badische Anilin und Soda Fabrik.
Phosgene can not be used alone in gas cylinders because of its high
boiling point (8° C.). While this is considerably below ordinary
temperatures, especially during the summer months, the rate of evaporation
is so slow that a cloud attack could never be made with it alone. However,
when a mixture of 25 per cent phosgene and 75 per cent chlorine, or 50 per
cent phosgene and 50 per cent chlorine is used in warm weather there is no
difficulty in carrying out gas attacks from cylinders. At the same time the
percentage of phosgene in the mixture is sufficiently high to secure the
advantages which it possesses. These advantages are at least three:
(a) Phosgene is more toxic than chlorine. It requires 2.5 milligrams per
liter of chlorine to kill a dog on an exposure of 30 minutes, but 0.3
milligram of phosgene will have the same effect. This of course means that
a cloud of phosgene containing one-eighth (by weight) of the concentration
of a chlorine cloud will have the same lethal properties.

(b) Phosgene is much less reactive than chlorine, so that the matter of
protection becomes more difficult. Fortunately, word was received by the
British of the intended first use of phosgene against them and consequently
they were able to add hexamethylenetetramine to the impregnating solution
used in the cloth masks.
(c) The third, and a very important, factor in the use of phosgene is the
so-called delayed effect. In low concentrations, men may breathe phosgene
for some time with apparently no ill effects. Ten or twelve hours later, or
perhaps earlier if they attempt any work, the men become casualties.
Pure phosgene has been used in projector attacks (described in Chapter
II). The substance has also been used in large quantities in shell; the
Germans also used shell containing mixtures with superpalite
(trichloromethyl chloroformate) or sneezing gas (diphenylchloroarsine).

Manufacture

Phosgene was first prepared by John Davy in 1812, by exposing a
mixture of equal volumes of carbon monoxide and chlorine to sunlight;
Davy coined the name “phosgene” from the part played by light in the
reaction. While phosgene may be prepared in the laboratory by a number of
other reactions, it was quite apparent that the first mentioned reaction is the
most economical of these for large scale production. The reaction is a
delicate one, however, and its application required extended investigation.
The United States was fortunate in that, for some months previous to the
war, the Oldbury Electrochemical Company had been working on the
utilization of their waste carbon monoxide in making phosgene. The results
of these investigations were given to the government and aided
considerably in the early work on phosgene at the Edgewood plant.

Fig. 23.—Furnace for Generating Carbon Monoxide.

Of the raw materials necessary for the manufacture of phosgene, the
chlorine was provided, at first by purchase from private plants, but later
through the Edgewood chlorine plant. After a sufficient supply of chlorine
was assured the next question was how to obtain an adequate supply of
carbon monoxide. A method for this gas had not been developed on a large
scale because it had never been necessary to make any considerable
quantity of it. The French and English passed oxygen up through a gas
producer filled with coke; the oxygen combines with the carbon, giving
carbon monoxide. The oxygen was obtained from liquid air, for which a
Claude liquid air machine may be used. The difficulty with this method of
preparing carbon monoxide was that the amount of heat generated was so
great that the life of the generators was short. Our engineers conceived the

idea of using a mixture of carbon dioxide and oxygen. The union of carbon
dioxide with carbon to form carbon monoxide is a reaction in which heat is
absorbed. Therefore by using the mixture of the two gases, the heat of the
one reaction was absorbed by the second reaction. In this way a very
definite temperature could be maintained, and the production of carbon
monoxide was greatly increased.

Fig. 24.—Catalyzer Boxes Used in the Manufacture of Phosgene.

Carbon dioxide was prepared by the combustion of coke. The gas was
washed and then passed into a solution of potassium carbonate. Upon
heating, this evolved carbon dioxide.
Phosgene was then prepared by passing the mixture of carbon monoxide
and chlorine into catalyzer boxes (8 feet long, 2 feet 9 inches deep and 11
inches wide), which are made of iron, lined with graphite and filled with a
porous form of carbon. Two sets of these boxes were used. In the first the

reaction proceeds at room temperature, and is about 80 per cent complete.
The second set of boxes were kept immersed in tanks filled with hot water,
and there the reaction is completed.
The resulting phosgene was dried with sulfuric acid and then condensed
by passing it through lead pipes surrounded by refrigerated brine.
The Germans prepared their phosgene by means of a prepared charcoal
(wood or animal). Carbon monoxide was manufactured by passing carbon
dioxide over wood charcoal contained in gas-fired muffles and was washed
by passing through sodium hydroxide. This was mixed with chlorine and
the mixture passed downward through a layer of about 20 cm. of prepared
charcoal contained in a cast iron vessel 80 cm. in diameter and 80 cm. deep.
By regulating the mixture so that there was a slight excess of carbon
monoxide, the phosgene was obtained with only one-quarter of one per cent
free chlorine. The charcoal (wood) was prepared by washing with
hydrochloric and other acids until free from soluble ash; it was then washed
with water and dried in vacuum. The size of the granules was about one-
quarter inch mesh. Their life averaged about six months.

Properties

Phosgene is a colorless gas at room temperatures, but becomes a liquid
at 8°. The odor of phosgene is suggestive of green corn or musty hay. One
liter of phosgene vapor weighs 4.4 grams (chlorine weights 3.22 grams). At
0° C., the liquid is heavier than water, having a specific gravity of 1.432. At
25°, the vapor exerts a pressure of about 25 pounds per square inch.
Phosgene is absorbed by solid materials, such as pumice stone and celite.
Pumice stone absorbs more than its own weight of phosgene. Thus 5.7
grams of pumice absorbed 7.4 grams phosgene, which completely
evaporated in 60 minutes. German shell have been found which contained
such a mixture (phosgene and pumice stone). While the apparent reason for
their use is to prevent the rapid evaporation of the phosgene, it is a question
whether such is the case, for a greater surface is really present in the case of
pumice stone than where the phosgene is simply on the ground. Phosgene is
slowly decomposed by cold water, rapidly by hot water. This reaction is
important because there is always moisture in the air, which would tend to
lower the concentration of the gas.

Phosgene is absorbed and decomposed by hexamethylenetetramine
(urotropine). This reaction furnished the basis of the first protection used by
the British. Later the catalytic decomposition of phosgene into carbon
dioxide and hydrochloric acid by the charcoal in the mask furnished
protection.
For most purposes a trace of chlorine in phosgene is not a disadvantage;
for example, when it is used in cylinders or projectors. Under certain
conditions, as when used as a solvent for sneezing gas, the presence of
chlorine must be avoided, since it reacts with the substance in solution,
usually producing a harmless material. Chlorine may be removed from
phosgene by passing the mixture through cotton seed oil.

Protection

It was mentioned above that hexamethylenetetramine (urotropine) was
used in the early pads (black veil and similar masks) and flannel helmets.
This was found to be satisfactory against chlorine and phosgene, in the
concentrations usually found during a cylinder attack. The mixture used
consisted of urotropine, sodium thiosulfate (“hypo”), sodium carbonate and
glycerine. The glycerine tended to keep the pads moist, while the other
chemicals acted as protective agents against the mixture of phosgene and
chlorine.
The introduction of the Standard Box Respirator with its charcoal-soda
lime filling increased very materially the protection against phosgene. In
this filling, the charcoal both absorbs the phosgene and catalyzes the
reaction with the moisture of the air with which the phosgene is mixed, to
form hydrochloric acid and carbon dioxide. Soda-lime absorbs phosgene
but does not catalyze its decomposition. This shows the advantage of the
mixture, since the hydrochloric acid, which is formed through the action of
the charcoal, is absorbed by the soda-lime. Experiments seem to indicate
that it does not matter which material is placed in the bottom of the canister,
but that an intimate mixture is the best arrangement. Using a concentration
of 5,000 parts per million (20.2 mg. per liter) a type H canister (see page
217) will give complete protection for about 40 minutes; when the air-gas
mixture passes at the rate of 16 liters per minute the efficiency or life of a
canister increases with a decrease in temperature, as is seen in the following

table (the concentration was 5,000 parts per million, the rate of flow 16
liters per minute)
Temperature Efficiency
° C. (Time in minutes)
-10 223
0 172
10 146
20 130
30 125
40 99
From these figures it is seen that at -10° C. the life is about 50 per cent
greater than at summer temperature. As would be expected the life of a
canister is shortened by increasing the concentration of phosgene in the
phosgene air mixture. This is illustrated by the following figures:
Concentration Life
p.p.m. (Time in minutes)
5,000 177
10,000 112
15,000 72
20,000 58
25,000 25
(25,000 p.p.m. is equal to 101.1 mg. per liter.)

There is rather a definite relation between the concentration of the gas
and the life of a canister at any given rate of flow. Many of these relations
have been expressed by formulas of which the following is typical. At 32
liters per minute flow, C⁰ ˙ ⁹ × T = 101,840, in which C is the
concentration and T the time.

Shell Filling

The empty shell, after inspection, are loaded on trucks, together with the
appropriate number of “boosters,” which screw into the top of the shell and
thereby close them. The trucks are run by an electric storage battery
locomotive to the filling unit. The shell are transferred by hand to a
conveyor, which carries the shell slowly through a cold room. During this
passage of about 30 minutes, the shell are cooled to about 0° F. The cooled
shell are transferred to shell trucks, each truck carrying 6 shell. These trucks
are drawn through the filling tunnel by means of a chain haul operated by
an air motor to the filling machine. Here the liquid phosgene is run into the
shell by automatic machines, so arranged that the 6 shell are at the same
time automatically filled to a constant void. The truck then carries the filled
shell forward a few feet to a small window, at which point the boosters are
inserted into the nose of the shell by hand. The final closing of the shell is
then effected by motors operated by compressed air. The filling and closing
machines are all operated by workmen on the outside of the filling tunnel.

Fig. 25.—Filling Livens’ Drums with Phosgene.

The filled shell are conveyed to the shell dump, where they are stored
for 24 hours, nose down on skids, in order to test for leaks.

Tactical Use

Phosgene was first used in cloud attacks in December, 1915. These
attacks continued for about nine months and were then gradually replaced,
to a large extent, by gas shell attacks. Phosgene was first found in German
projectiles in November, 1916. These shell were known as the d-shell.
Besides pure phosgene, mixtures of phosgene and chloropicrin, phosgene
and superpalite, and phosgene and diphenylchloroarsine have been found.

Fig. 26.—Interior of a Shell Dump.

The English introduced the use of projectors in the Spring of 1917.
They have a decided advantage over shell in that they hold a larger volume
of gas and readily lend themselves to surprise attacks. As the Germans say,

“the projector combines the advantages of gas clouds and gas shell. The
density is equal to that of gas clouds and the surprise effect of shell fire is
also obtained.”
Toward the close of the war, the Germans made use of a mixture of
phosgene and pumice stone. A captured projector contained about 13
pounds of phosgene and 5½ pounds of pumice. There seems to be some
question as to the value of such a procedure. Lower initial concentrations
are secured; this is due, in part of course, to the smaller volume of phosgene
in the shell containing pumice. Pumice does seem to keep the booster from
scattering the phosgene so high into the air, and at the same time does not
prevent the phosgene from being liberated in a gaseous condition. This
would indicate that pumice gives a more even and uniform dispersion and a
more economical use of the gas actually used.
Owing to its non-persistent nature (the odor disappears in from one and
a half to two hours) and to its general properties, phosgene really forms an
ideal gas to produce casualties.

Action on Man

Phosgene acts both as a direct poison and as a strong lung irritant,
causing rapid filling of the lungs with liquid. The majority of deaths are
ascribed to the filling up of the lungs and consequently to the suffocation of
the patients through lack of air. This filling up of the lungs is greatly
hastened by exercise. Accordingly, all rules for the treatment of patients
gassed with phosgene require that they immediately lie down and remain in
that position. They are not even allowed to walk to a dressing station. The
necessity of absolute quiet for gassed patients undoubtedly partly accounts
for the later habit of carrying out a prolonged bombardment after a heavy
phosgene gas attack. The high explosive causes confusion, forcing the men
to move about more or less and practically prevents the evacuation of the
gassed. In the early days of phosgene the death rate was unduly high
because of lack of knowledge of this action of the gas. Due to the decreased
lung area for oxygenizing the air, a fearful burden is thrown on the heart,
and accordingly, those with a heart at all weak are apt to expire suddenly
when exercising after being gassed.

As an illustration of the delayed action of phosgene, a large scale raid
made by one of the American divisions during its training is highly
illuminating.
This division decided to make a raid on enemy trenches which were
situated on the opposite slope of a hill across a small valley. Up stream from
both of the lines of trenches was a French village in the hands of the
Germans. When the attack was launched the wind was blowing probably six
or seven miles per hour directly down stream from the village, i.e., directly
toward the trenches to be attacked. The usual high explosive box barrage
was put around the trenches it was intended to capture.
Three hundred Americans made the attack. During the attack a little
more than three tons of liquid phosgene was thrown into the village in 75-
and 155-millimeter shells. The nearest edge of the village shelled with
phosgene was less than 700 yards from the nearest attacking troops. None
of the troops noticed the smell of phosgene, although the fumes from high
explosive were so bad that a few of the men adjusted their respirators. The
attack was made about 3 a.m., the men remaining about 45 minutes in the
vicinity of the German trenches. The men then returned to their billets,
some five or six kilometers back of the line. Soon after arriving there, that
is in the neighborhood of 9 a.m., the men began to drop, and it was soon
discovered that they were suffering from gas poisoning. Out of the 300 men
making the attack 236 were gassed, four or five of whom died.
The Medical Department was exceedingly prompt and vigorous in the
treatment of these cases, which probably accounted for the very low
mortality.
This is one of the most interesting cases of the delayed action that may
occur in gassing from phosgene. Here the concentration was slight and
there is no doubt its effectiveness was largely due to the severe exercise
taken by the men during and after the gassing.
It should be remarked in closing that while gas officers were not
consulted in the planning of this attack, a general order was shortly
thereafter issued requiring that gas officers be consulted whenever gas was
to be used.

CHAPTER VII
LACHRYMATORS
Without question the eyes are the most sensitive part of the body so far
as chemical warfare is concerned. Lachrymators are substances which affect
the eyes, causing involuntary weeping. These substances can produce an
intolerable atmosphere in concentrations one thousand times as dilute as
that required for the most effective lethal agent. The great military value of
these gases has already been mentioned and will be discussed more fully
later.
There are a number of compounds which have some value as
lachrymators, though a few are very much better than all the others.
Practically all of them have no lethal properties in the concentrations in
which they are efficient lachrymators, though we must not lose sight of the
fact that many of them have a high lethal value if the concentration is of the
order of the usual poison gas. The lachrymators are used alone when it is
desired to neutralize a given territory or simply to harrass the enemy. At
other times they are used with lethal gases to force the immediate or to
prolong the wearing of the mask.
A large number of the lachrymators contain bromine. In order to
maintain the gas warfare requirements, it was early decided that the
bromine supply would have to be considerably increased. The most
favorable source of bromine is the subterranean basin found in the vicinity
of Midland, Michigan. Because of the extensive experience of the Dow
Chemical Co. in all matters pertaining to the production of bromine, they
were given charge of the sinking of seventeen government wells, capable of
producing 650,000 pounds of bromine per year. While the plant was not
operated during the War, it was later operated to complete a contract for
500,000 pounds of bromine salts. They will be held as a future war asset of
the United States.
The principal lachrymators used during the War were:

Bromoacetone,

Bromomethylethylketone,
Benzyl bromide,
Ethyl iodoacetate,
Bromobenzyl cyanide,
Phenyl carbylamine chloride.

Chloropicrin is something of a lachrymator, but it has greater value as a
toxic gas.

Halogenated Ketones

One of the earliest lachrymators used was bromoacetone. Because of the
difficulty of obtaining pure material, the commercial product, containing
considerable dibromoacetone and probably higher halogenated bodies, was
used. The presence of these higher bromine derivatives considerably
decreased its efficiency as a lachrymator. The preparation of bromoacetone
involved the loss of considerable bromine in the form of hydrobromic acid.
This led the French to study various methods of preparation, and they
finally obtained a product containing 80 per cent bromoacetone and 20 per
cent chloroacetone, which they called “martonite.” As the war progressed,
acetone became scarce, and the Germans substituted methylethylketone, for
which there was little use in other war activities. This led to the French
“homomartonite.”
Various other halogen derivatives of ketones have been studied in the
laboratory, but none have proven of as great value as bromoacetone, either
from the standpoint of toxicity or lachrymatory power.
Bromoacetone may be prepared by the action of bromine (liquid or
vapor) upon acetone (with or without a solvent). Aqueous solutions of
acetone, or potassium bromide solutions of bromine, have also been used.
Pure bromoacetone is a water clear liquid. There are great differences in
the properties ascribed to this body by different investigators. This probably
is due to the fact that the monobromo derivative is mixed with those
containing two or more atoms of bromine. A sample boiling at 126-127°
and melting at -54°, had a specific gravity of 1.631 at 0°. It has a vapor
pressure of 9 mm. of mercury at 20°.

While bromoacetone is a good lachrymator, it possesses the
disadvantage that it is not very stable. Special shell linings are necessary,
and even then the material may be decomposed before the shell is fired. The
Germans used a lead-lined shell, while considerable work has been carried
out in this country with enamel lined shell. Glass lined shell may also be
used. It is interesting to note that, while bromoacetone decomposes upon
standing in the shell, it is stable upon detonation. No decomposition
products are found after the explosion, and even unchanged liquid is found
in the shell. It may be considered as having a low persistency, since the
odor entirely disappears from the surface of the ground in twenty-four
hours.
Bromoacetone was also used by the Germans in glass hand grenades
(Hand-a-Stink Kugel) and later in metal grenades. The metal grenades
weighed about two pounds and contained about a pound and a half of the
liquid.
Martonite was prepared by the French in an attempt more completely to
utilize the bromine in the preparation of bromoacetone. They regenerated
the bromine by the use of sodium chlorate:
NaClO₃ + 6HBr = NaCl + 3Br₂ + 3H₂O
In practice sulfuric acid is used with the sodium chlorate, so that the
final products are sodium acid sulfate and a mixture of 20 per cent
chloroacetone and 80 per cent bromoacetone, according to the reaction:
5(CH₃)₂CO + 4Br + H₂SO₄ + NaClO₃ =
4CH₂BrCOCH₃ + CH₂ClCO CH₃ + NaHSO₄ + 3H₂O.
This product is equally as effective as bromoacetone alone and is very
much cheaper to manufacture. In general its properties resemble very
closely those of bromoacetone.

German Manufacture of Bromoacetone
and Bromomethylethyl ketone
[17]

These two products were prepared by identical methods. About two-
thirds of the product produced by the factory was prepared from

methylethyl ketone which was obtained from the product resulting from the
distillation of wood. The method employed was to treat an aqueous solution
of potassium or sodium chlorate with acetone or methylethyl ketone, and
then add slowly the required amount of bromine. The equation for the
reaction in the case of acetone is as follows:
CH₃COCH₃ + Br₂ = CH₂BrCOCH₃ + HBr
Ten kg.-mols of acetone or methylethyl ketone were used in a single
operation. About 10 per cent excess of chlorate over that required to oxidize
the hydrobromic acid formed in the reaction was used. The relation between
the water and the ketone was in the proportion of 2 parts by weight of the
former to 1 part by weight of the latter. For 1 kg.-mol. wt. of the ketone, 10
per cent excess over 1 kg. atomic-weight of bromine was used.
The reaction was carried out either in earthenware vessels or in iron
kettles lined with earthenware. The kettles were furnished with a stirrer
made of wood, and varied in capacity from 4,000 to 5,000 liters. They were
set in wooden tanks and cooled by circulating water. The chlorate was first
dissolved in the water and then the ketone added. Into this mixture the
bromine was allowed to run slowly while the solution was stirred and kept
at a temperature of from 30° to 40° C. The time required for the addition of
the bromine was about 48 hrs. When the reaction was complete, the oil was
drawn off into an iron vessel and stirred with magnesium oxide in the
presence of a small amount of water in order to neutralize the free acid. It
was then separated and dried with calcium chloride. At this point a sample
of the material was taken and tested. The product was distilled to tell how
much of it boiled over below 130° when methylethyl ketone had been used.
If less than 10 per cent distilled over, the bromination was considered to be
satisfactory. If, however, a larger percentage of low boiling material was
obtained, the product was submitted to further bromination. The material
obtained in this way was found on analysis to contain slightly less than the
theoretical amount of monobromoketone.
It was finally transferred by suction or by pressure into tank-wagons. At
first lead-lined tanks were used, but later it was found that tanks made of
iron could be substituted. In order to take care of the small amount of
hydrobromic acid, which is slowly formed, a small amount of magnesium
oxide was added to the material. The amount of the oxide used was

approximately in the proportion of 1 part to 1000 parts of ketone. When the
magnesium oxide was used, it was found that the bromoketone kept without
appreciable decomposition for about 2 months. The yield of the product
from 580 kg. of acetone (10 kg.-mol. wts.) was 1,100 kg. The yield from
720 kg. of methylethyl ketone (10 kg.-mol. wts.) was 1,250 kg.

Halogenated Esters

The use of ethyl iodoacetate was advocated at a time when the price of
bromine seemed prohibitive. Because of the relative price of bromine and
iodine under ordinary conditions, it is not likely that it would be commonly
used. However, it is an efficient lachrymator and is more stable than the
halogenated ketones, so that on a smaller scale it might be advisable to use
it.
It is prepared by the reaction of sodium iodide upon an alcoholic
solution of ethyl chloroacetate. It is a colorless oil, boiling at 178-180° C.
(69° C. at 12 mm.) and having a density of about 1.8. It is very much less
volatile than bromoacetone, having a vapor pressure of 0.54 mm. of
mercury at 20° C. Ethyl iodoacetate is about one-third as toxic as
bromoacetone, but has about the same lachrymatory value.

Aromatic Halides

“Benzyl bromide” was also used during the early part of the war,
usually mixed with bromoacetone. The material was not pure benzyl
bromide, but the reaction product of bromine upon xylene, and should
perhaps be referred to as “xylyl bromide.”
Pure benzyl bromide is a colorless liquid, boiling at 198-199° C., and
having an odor reminiscent of water cress and then of mustard oil. The war
gas is probably a mixture of mono- and dibromo derivatives, boiling at 210-
220° C., and having a density at 20° C. of 1.3. The mixture of benzyl and
xylyl bromides used by the Germans was known as “T-Stoff,” while the
mixture of 88 per cent xylyl bromide and 12 per cent bromoacetone was
called “Green T-Stoff.”

As in the case of the halogenated acetones, it is necessary to use lead
lined shell for these compounds. Enamel and glass lined shell may be used
and give good results. While they are difficult of manufacture, satisfactory
methods were being developed at the close of the war.
“T-Stoff” may be detected by the nose in concentrations of one part in
one hundred million of air, and will cause profuse lachrymation with one
part in a million. It is a highly persistent material and may last, under
favorable circumstances, for several days. While it is relatively non-toxic,
French troops were rendered unconscious by it during certain
bombardments in the Argonne in the summer of 1915.
A number of derivatives of the benzyl halides have been tested and
some have proven to be very good lachrymators. The difficulty of their
preparation on a commercial scale has made it inadvisable to use them, and
especially inasmuch as bromobenzyl cyanide has proven to be such a
valuable compound.

Bromobenzyl Cyanide

Bromobenzyl cyanide is, chemically, α-bromo-α-tolunitrile, or phenyl-
bromo-acetonitrile, C₆H₅CHBrCN. It is prepared by the action of
bromine upon benzyl cyanide.
Benzyl cyanide is prepared by the action of sodium cyanide upon a
mixture of equal parts of 95 per cent alcohol and benzyl chloride. The
benzyl chloride in turn is obtained by the chlorination of toluene at 100°.
The material must be fairly pure in order that the benzyl cyanide reaction
may proceed smoothly. The cyanide is subjected to a fractional distillation
and that part boiling within 3 degrees (the pure product boils at 231.7° C.)
is treated with bromine vapor mixed with air. It has been found necessary to
catalyze the reaction by sunlight, artificial light or the addition of a small
amount of bromobenzyl cyanide.
The product obtained from this reaction, if the hydrobromic acid which
is formed is carefully removed by a stream of air, is sufficiently pure for use
as a lachrymator. It melts from 16 to 22° C., while the pure product melts at
29° C. It cannot be distilled, even in a high vacuum. It has a low vapor
pressure and thus is a highly persistent lachrymator.

Bromobenzyl cyanide is about as toxic as chlorine, but is many times as
effective a lachrymator as any of the halogenated ketones or aromatic
halides studied. It has a pleasant odor and produces a burning sensation on
the mucous membrane.
Like the other halogen containing compounds, lead or enamel lined
shell are necessary for preserving the material any length of time. In all of
this work the United States was at a very marked disadvantage. While the
Allies and the Germans could prepare substances of this nature and use
them in shell within a month, the United States was sure that shell filled at
Edgewood Arsenal probably would not be fired within three months. This
means that much greater precautions were necessary, both as to the nature
of the shell lining and as to the purity of the “war gas.”
The question of protection against lachrymatory gases was never a
serious one. During the first part of the war this was amply supplied by
goggles. Later, when the Standard Respirator was introduced, it was found
that ample protection was afforded against all the lachrymators. Their
principal value is against unprotected troops and in causing men to wear
their masks for long periods of time.
The comparative value of the various lachrymators mentioned above is
shown in the following table:
Bromobenzyl cyanide 0.0003
Martonite 0.0012
Ethyl iodoacetate 0.0014
Bromoacetone 0.0015
Xylyl bromide 0.0018
Benzyl bromide 0.0040
Bromo ketone 0.011
Choroacetone 0.018
Chloropicrin 0.019
The figures give the concentration (milligram per liter of air) necessary
to produce lachrymation. The method used in obtaining these figures is
given in Chapter XXI.

CHAPTER VIII
CHLOROPICRIN
During the spring of 1917, strange reports came from the Italian front
that the Germans were using a new war gas. This gas, while it did not seem
to be very poisonous, had the combined property of being a lachrymator
and also of causing vomiting. Large number of casualties resulted through
the men being forced to remove their masks in an atmosphere filled with
lethal gases. The gas had the additional and serious disadvantage of being a
very difficult one to remove completely in the gas mask. The first American
masks were very good when chlorine or phosgene was considered but were
of no value when chloropicrin was used.
One of the interesting facts of chemical warfare is that few if any new
substances were discovered and utilized during the three years of this form
of fighting. Chlorine and phosgene were well known compounds. And
likewise, chloropicrin was an old friend of the organic chemist. So much so,
indeed, that several organic laboratories prepared the compound in their
elementary courses.
Chloropicrin was first prepared by the English chemist, Stenhouse, in
1848, by the action of bleaching powder upon a solution of picric acid. This
was followed by a careful study of its physical and chemical properties, few
of which have any connection with its use as a poison gas. The use of picric
acid as an explosive made it very desirable that other raw materials should
be used. Chloroform, which is the ideal source theoretically (since
chloropicrin is nitro-chloroform, Cl₃CNO₂), gave very poor yields. While it
may be prepared from acetone, in fair yields, acetone was about as valuable
during the war as was picric acid. Practically all the chloropicrin used was
prepared from this acid as the raw material.

Manufacture

In the manufacture of chloropicrin the laboratory method was adopted.
This consisted simply in passing live steam through a mixture of picric acid

and bleaching powder. The resulting chloropicrin passes out of the still with
the steam. There was a question at first whether a steam jacketed reaction
vessel should be used, and whether stirrers should be introduced. Both types
were tested, of which the simpler form, without steam jacket or stirrer,
proved the more efficient.

Fig. 27.—Interior of Chloropicrin Plant.

The early work was undertaken at the plant of the American Synthetic
Color Company at Stamford, Connecticut. Later a large plant was
constructed at Edgewood Arsenal. At the latter place ten stills, 8 by 18 feet,
were erected, together with the necessary accessory equipment. The
following method of operation was used:
The bleach is mixed with water and stirred until a cream is formed. This
cream is then pumped into the still along with a solution of calcium picrate
(picric acid neutralized with lime). When the current of live steam is

admitted at the bottom of the still, the temperature gradually rises, until at
85° C. the reaction begins. The chloropicrin passes over with the steam and
is condensed. Upon standing, the chloropicrin settles out, and may be drawn
off and is then ready for filling into the shell. The yield was about 1.6 times
the weight of picric acid used.

Properties

Chloropicrin is a colorless oil, which is insoluble in water, and which
can be removed from the reaction by distillation with steam. It boils at 112°
C. and will solidify at -69° C. At room temperature it has a density of 1.69
and is thus higher than chloroform (1.5) or carbon tetrachloride (1.59). At
room temperature it has a vapor pressure of 24 mm. of mercury. It thus lies,
in persistency, between such gases as phosgene on the one hand, and
mustard gas on the other, but so much closer to phosgene that it is placed in
the phosgene group.
Chloropicrin is a very stable compound and is not decomposed by
water, acids or dilute alkalies. The reaction with potassium or sodium
sulfite, in which all the chlorine is found as potassium or sodium chloride,
has been used as an analytical method for its quantitative determination.
The qualitative test usually used consists in passing the gas-air mixture
through a heated quartz tube, which liberates free chlorine. The chlorine
may be detected by passing through a potassium iodide solution containing
starch, or by the use of a heated copper wire gauze, when the characteristic
green color is obtained.
An interesting physiological test has also been developed. The eye has
been found to be very sensitive to chloropicrin. The gas affects the eye in
such a way that its closing is practically involuntary. A measurable time
elapses between the instant of exposure and the time when the eye closes.
Below 1 or 2 parts per million, the average eye withstands the gas without
being closed, though considerable blinking may be caused. Above 25 parts,
the reaction is so rapid as to render proper timing out of the question. But
with concentrations between 2 and 25 parts, the subject will have an
overpowering impulse to close his eye within 3 to 30 seconds. The time
may be recorded by a stop watch and from the values thus determined a
calibration curve may be plotted, using the concentration in parts per

million and the time to zero eye reaction. Typical figures are given below. It
will be noted that different individuals will vary in their sensitivity, though
the order is the same.

Conc. A B
p.p.m. Seconds Seconds
20.0 4.0 5.0
15.0 5.4 5.4
10.0 7.5 7.5
7.5 9.0 10.0
5.0 13.0 15.0
2.5 18.0 30.0

Fig. 28.—Calibration Curve of Eyes for Chloropicrin.

Protection

Because of the stability of chloropicrin, the question of protection
resolves itself into finding an absorbent which is very efficient in removing

the gas from air mixtures. Fortunately such an agent was found in the
activated charcoal used in the American gas mask. The removal of the gas
appears to take place in two stages. In the first, the gas is adsorbed in such a
way that the long-continued passage of air does not remove it. In the
second, the gas is absorbed, and this, really excess gas, is removed by pure
air passing over the charcoal. The relation of these two factors has an
important bearing on the quality of charcoal to be used in gas masks. It
appears that up to a certain point an increase of the quality is desirable:
beyond this, it is of doubtful value.
Unlike phosgene, chloropicrin is absorbed equally well at all
temperatures. Moisture on the other hand has a very decided effect. It
appears that charcoal absorbs roughly equivalent weights of chloropicrin
and of water; the presence of water in the charcoal thus displaces an
approximately equal amount of chloropicrin.
In the study of canisters it has been found that the efficiency time is
approximately inversely proportional to the concentration. Formulas have
been calculated to express the relation existing between concentration and
life of the canister, and also between the rate of flow of the gas and the life.
While water seems to have a decidedly marked effect upon the life of a
canister, this is not true of other gases, and the efficiency of the canister for
each gas is not decreased when used in a binary mixture.

Tactical Uses

Because of the high boiling point of chloropicrin it can only be used in
shell. The German shell usually contained a mixture of superpalite
(trichloromethyl chloroformate) and chloropicrin, the relative proportions
being about 75 to 25. These were called Green Cross Shell, from the
peculiar marking on the outside of the shell. Mixtures of phosgene and
chloropicrin (50-50) have also been used.
The Allies have used a mixture of 80 per cent chloropicrin and 20 per
cent stannic chloride (so-called N. C.). This mixture combines the
advantages of a gas shell with those of a smoke shell, since the percentage
of stannic chloride is sufficiently high to form a very good cloud. In
addition to this, it is believed that the presence of the chloride increases the

rate of evaporation of the chloropicrin. It has been claimed that the chloride
decreases the amount of decomposition of the chloropicrin upon the
bursting of the shell, but careful experiments appear to show that this
decomposition is negligible and that the stannic chloride plays no part in it.
This mixture was being abandoned at the close of the war.
This N. C. mixture has also been used in Liven’s projectors and in hand
grenades. The material is particularly fitted for hand grenades, owing to the
low vapor pressure of the chloropicrin, and the consequent absence of
pressures even on warm days. As a matter of fact, it was the only filling
used for this purpose, though later the stannic chloride was changed, owing
to the shortage of tin, to a mixture of silicon and titanium chlorides.
While chloropicrin is sufficiently volatile to keep the strata of air above
it thoroughly poisonous, it is still persistent enough to be dangerous after
five or six hours.

CHAPTER IX
DICHLOROETHYLSULFIDE
“MUSTARD GAS”
The early idea of gas warfare was that a material, to be of value as a war
gas, should have a relatively high vapor pressure. This would, of course,
provide a concentration sufficiently high to cause casualties through
inhalation of the gas-ladened air. The introduction of “mustard gas”
(dichloroethylsulfide) was probably the greatest single development of gas
warfare, in that it marked a departure from this early idea, for mustard gas
is a liquid boiling at about 220° C., and having a very low vapor pressure.
But mustard gas has, in addition, a characteristic property which, combined
with its high persistency, makes it the most valuable war gas known at the
present time. This peculiar property is its blistering effect upon the skin.
Very low concentrations of vapor are capable of “burning” the skin and of
producing casualties which require from three weeks to three months for
recovery. The combination of these properties removed the necessity for a
surprise attack, or the building up of a high concentration in the first few
bursts of fire. A few shell, fired over a given area, were sufficient to
produce casualties hours and even days afterwards.
Mustard gas, chemically, is dichloroethylsulfide (ClCH₂CH₂)₂S. The
name originated with the British Tommy because the crude material first
used by the Germans was suggestive of mustard or garlic. Various other
names were given the compound, such as “Yellow Cross,” from the shell
markings of the Germans; “Yperite,” a name used by the French, because
the compound was first used at Ypres; and “blistering gas,” because of its
peculiar effect upon the skin.

Historical

It seems probable that an impure form of mustard gas was obtained by
Richie (1854) by the action of chlorine upon ethyl sulfide. The substance
was first described by Guthrie (1860), who recognized its peculiar and

powerful physiological effects. It is interesting in this connection to note
that Guthrie studied the effect of ethylene upon the sulfur chlorides, since
this reaction was the basis of the method finally adopted by the Allies.
The first careful investigation of mustard gas, which was then only
known as dichloroethylsulfide, was carried out by Victor Meyer (1886).
Meyer used the reaction between ethylene chlorhydrin and sodium sulfide,
with the subsequent treatment with hydrochloric acid. All the German
mustard gas used during 1917 and 1918 was apparently made by the use of
these reactions, and all the early experimental work of the Allies was in this
direction.
Mustard gas was first used as an offensive agent by the Germans on
July 12-13, 1917, at Ypres. According to an English report, the
physiological properties of mustard gas had been tested by them during the
summer of 1916. The Anti-Gas Department put forward the suggestion that
it should be used for chemical warfare, but at that time its adoption was not
approved. This fact enabled the English to quickly and correctly identify the
contents of the first Yellow Cross dud received. It is not true, as reported by
the Germans, that the material was first diagnosed as diethylsulfide.
The tactical value of mustard gas was immediately recognized by the
Germans and they used tremendous quantities of it. During ten days of the
Fall of 1917, it is calculated that over 1,000,000 shell were fired, containing
about 2,500 tons of mustard gas. Zanetti states that the British gas casualties
during the month following the introduction of mustard gas were almost as
numerous as all gas casualties incurred during the previous years of the war.
Pope says that the effects of mustard gas as a military weapon were indeed
so devastating that by the early autumn of 1917 the technical advisers of the
British, French, and American Governments were occupied upon large scale
installations for the manufacture of this material.

Preparation and Manufacture

The analysis of the first German shell indicated that the mustard gas
contained therein had been prepared by the method published by Victor
Meyer (1886) and later used by Clark (1912) in England. It was natural,
therefore, that attention should be turned to the large scale operation of this
method.

The following operations are involved: Ethylene is prepared by the
dehydration of ethyl alcohol. The interaction of hypochlorous acid (HClO)
and ethylene yields ethylene chlorhydrin, ClCH₂CH₂OH. When this is
treated with sodium sulfide, dihydroxyethyl sulfide forms, which, heated
with hydrochloric acid, yields dichloroethyl sulfide. Chemically, the
reactions may be written as follows:
CH₃CH₂OH = CH₂ : CH₂ + H₂O
CH₂ : CH₂ + HClO = HOCH₂CH₂Cl
2HOCH₂CH₂Cl + Na₂S = (HOCH₂CH₂)₂S + 2NaCl
(HOCH₂CH₂)₂S + 2HCl = (ClCH₂CH₂)₂S + 2H₂O
Without going into the chemistry of this reaction, which is thoroughly
discussed by Gomberg[18] (see also German Manufacture), it may be said
that this “procedure proved to be unsuitable for large scale production”
(Dorsey). As Pope remarks, “That he (the German) should have been able
to produce three hundred tons of mustard gas per month by the large scale
installation of the purely academic method (of Meyer) constitutes indeed ‘a
significant tribute to the potentialities represented by the large German fine
chemical factories.’” It is true that a great deal of experimental work was
carried out by the Allies on this method, but further study was dropped as
soon as the Pope method was discovered.
The first step in advance in the manufacture of mustard gas was the
discovery that ethylene would react with sulfur dichloride. While American
chemists were not very successful in their application of this reaction, either
in the laboratory or the plant, it was apparently, according to Zanetti, the
only method used by the French (the only one of the Allies that
manufactured and fired mustard gas). The plant was that of the Société
Chimique des Usines du Rhone and was started early in March, 1918, with
a production of two to three tons a day. In July it was producing close to
twenty tons a day. The plant was being duplicated at the time of the
Armistice, so that probably in December, 1918, the production of mustard
gas by the dichloride process would have reached about 40 tons. Zanetti
points out, however, that the process involved complicated and costly
apparatus and required considerable quantities of carbon tetrachloride as a

solvent. It is for this reason that the Levinstein process would have been a
tremendous gain, had the war continued.
About the end of January, 1918, Pope and Gibson, in a study of the
reaction originally used by Guthrie, found that the action of ethylene upon
sulfur chloride (S₂Cl₂) at 60° yielded mustard gas and sulfur:
2CH₂ : CH₂ + S₂Cl₂ = (CH₂ClCH₂)₂S + S
The reaction at this temperature caused the separation of sulfur; this
occurred after the product stood for some time or immediately if it was
treated with moist ammonia gas. While this process was put into
commercial operation, both in England and America, it offered considerable
difficulty from an operating standpoint. The sulfur would often separate out
and block the inlet tubes (ethylene). While it is comparatively easy to
remove the mustard gas from the separated sulfur by decantation, a certain
amount always remains with the sulfur. It is almost impossible to
economically remove this, and its presence adds to the difficulty of
removing the sulfur from the reactors; the men engaged in this operation
almost always become casualties.

Fig. 29.—The Levinstein Reactor
as Installed at Edgewood Arsenal.

It was especially important, therefore, when Green discovered that, if
the reaction was carried out at 30°, the sulfur did not settle out but remained
in “pseudo solution” in the mustard gas (Pope) or as a loose chemical
combination of the monosulfide (mustard gas) with an atom of sulfur
(Green). This material has all the physiological activity of the pure
monosulfide, while the enormous technical difficulties of handling
separated sulfur are entirely obviated by this method of manufacture. To
carry out the reaction Levinstein, Ltd., devised the Levinstein “reactor.” The
apparatus is shown in Fig. 29. The process consists essentially in bringing
together sulfur chloride and very pure ethylene gas in the presence of crude
mustard gas as a solvent at a temperature ranging between 30-35° C. A
supply of unchanged monochloride is constantly maintained in the reacting
liquid until a sufficiently large batch is built up. Then the sulfur
monochloride feed is discontinued and the ethylene feed continued until

further absorption ceases. By controlling the ratio of mustard gas to
uncombined monochloride, the reaction velocity is so increased that the
lower temperature may be used.
The product thus obtained is a pale yellow liquid which deposits no
sulfur and requires no further treatment. It is ready for the shell filling plant
at once. The obvious advantage of this method led to its adoption in all
American plants started for the manufacture of mustard gas (Edgewood,
Cleveland and Buffalo).

Ethylene

It was known from the work of certain French chemists that in the
presence of such a catalyst as kaolin, ethyl alcohol is dehydrated at an
elevated temperature to ethylene. The process as finally developed by
American chemists consisted essentially in introducing mixtures of alcohol
vapor and steam, in the ratio of one to one by weight, into an 8-inch iron
tube with a 3-inch core, in contact with clay at 500-600° C. The use of
steam rendered the temperature control more uniform and thus each unit
had a greater capacity of a higher grade product. The gaseous products were
removed through a water-cooled surface condenser. One unit of this type
had a demonstrated capacity of 400 cubic feet per hour of ethylene, between
92 and 95 per cent pure, while the conversion efficiency (alcohol to
ethylene) was about 85 per cent. The Edgewood plant consisted of 40 such
units. This would have yielded sufficient ethylene to make 40 tons of
mustard gas per 24-hour day.
The English procedure consisted in the use of phosphoric acid, absorbed
onto coke. An American furnace was designed and built which gave 2,000
cubic feet per hour of ethylene, with a purity of 98 to 99 per cent. This
furnace was not used on a large scale, because of the satisfactory nature of
the kaolin furnaces.

Fig. 30.—Experimental Installation for the Production
of Ethylene by Kaolin Procedure.
Capacity 400-600 cu. ft. Ethylene per hr.

Sulfur Chloride

Since chlorine was prepared at Edgewood, it was logical that some of
this chlorine should be utilized in the preparation of sulfur chloride. The
plant constructed consisted of 30 tanks (78 inches in diameter and 35 feet
long), each capable of producing 20,000 pounds of monochloride per day.
The tanks are partially filled with sulfur and chlorine passed in. The
reaction proceeds rapidly with sufficient heat to keep the sulfur in a molten
condition. If the chlorine is passed in too rapidly, the heat generated may be
sufficient to boil off the sulfur chloride formed. Hence water pipes are
provided so that a supply of cold water may be sprayed upon the tanks,
keeping the temperature within the proper limits.

Fig. 31.—Row of Furnaces for the Preparation of Ethylene.

In the manufacture of one ton of mustard gas, about one ton of sulfur
chloride and a little less than half a ton of ethylene (12,640 cubic feet) are
required.

German Method of Manufacture[19]

Fig. 32.—Preparation of Ethylene at
Badische Anilin und Soda Fabrik. 60 units.

“Preparation of Ethylene—The gas was prepared by
passing alcohol vapor over aluminum oxide at a
temperature of 380° to 400°. The details of the
construction of one of the furnaces are given in Figs. 32
and 33. The furnaces were very small and sixty units
were needed to furnish the amount of gas required. The
tubes containing the catalyzer were made of copper and
were heated in a bath of molten potassium nitrate. It was
stated that the catalyzer was made according to the
directions of Ipatieff, and that its life was from 10 to 20
days. The gas produced was washed in the usual form of
scrubber. The yield of ethylene was stated to be about 90
per cent of the theoretical.

Fig. 33.—Ethylene Production at
Badische Anilin und Soda Fabrik. 1 unit.

Fig. 34.—Chlorhydrin reaction kettle at
Badische Anilin und Soda Fabrik. 16 units.

“Preparation of Ethylene Chlorhydrin—The
reaction was carried out in a cylindrical tank resting on
its side. The tank was furnished with a stirrer and was
insulated by means of cork in order to prevent the
transfer of heat from the atmosphere to the inside.
Enough chloride of lime was introduced into the tank to
furnish 500 kg. of available chlorine, together with 5 cu.
m. of water. At first, about 20 cu. m. of carbon dioxide
were led into the mixture, next ethylene, and later carbon
dioxide and ethylene simultaneously. The rate of
absorption of ethylene was noted and when it slackened,
more carbon dioxide was added. Fuller details as to the
addition of the two gases were not given as it was stated
that it was a matter of judgment on the part of the
workman who was carrying out the operation. The
reaction should be carried out at as low a temperature as
possible, but it was found impossible to work below 5°
with the apparatus employed in this factory. The
temperature during the reaction varied between 5° and
10°. In order to maintain this temperature, the solution
was constantly pumped from the apparatus through a coil
which was cooled by brine. When ethylene was no longer
absorbed and there was an excess of carbon dioxide
present, the solution was tested for hypochlorous acid.
The time required for the introduction of ethylene was
between 2 and 3 hrs.
“The contents of the apparatus were passed through a
filter press by means of which the calcium carbonate was
removed. The solution thus obtained contained from 10
to 12 per cent of ethylene chlorhydrin. It was next
distilled with steam and a distillate collected which
contained between 18 and 20 per cent of chlorhydrin. The
yield of chlorhydrin was from 60 to 80 per cent of that
calculated from the ethylene used.

Fig. 35.—Mustard Gas Manufacture at Leverkusen.
Layout for Chlorination of Thiodiglycol.

“Preparation of Dihydroxyethylsulfide—To prepare
the hydroxysulfide, the theoretical quantity of sodium
sulfide, either in the form of the anhydrous salt or as
crystals, was added to the 18 to 20 per cent solution of
chlorhydrin. After the addition of the sulfide, the mixture
was heated to about 90° to 100°. It was then pumped to
an evaporator, and heated until all the water was driven
off. The glycol was next filtered from the salt which
separated, and distilled in a vacuum. The yield of glycol

was about 90 per cent of the theoretical, calculated from
the chlorhydrin.
“Preparation of Dichlorethylsulfide—The
thiodiglycol was taken from the rail to two large storage
tanks and thence drawn by vacuum direct to the reaction
vessel. Each reaction vessel was placed in a separate
cubicle ventilated both from above and below and fitted
with glass windows for inspection. The vessels
themselves were made of 1¼ in. cast iron and lined with
10 mm. lead. They were 2.5 m. high and 2.8 m. in
diameter. These tanks were jacketed so that they could be
heated by water and steam, and the reaction was carried
out at 50°. The hydrochloric acid coming from the main
pipe was passed through sulfuric acid so that the rate
could be observed, and passed in by means of 12 glass
tubes of about 2 cm. diameter. The rate of flow was
maintained at as high a rate as possible to procure
absorption. The vapors from the reaction were led from
the vessel through a pipe into a collecting room, and then
through a scrubber containing charcoal and water,
through a separator, and then, finally, into the chimney.
These exhaust gases were drawn off by means of a fan
which was also connected with the lower part of the
chamber in which the reaction vessels were set, so that all
the gases had to pass through the scrubber before going
to the chimney. When the reaction was completed, the oil
was removed by means of a vacuum, induced by a water
pump, into a cast iron washing vessel.
“The hydrochloric acid layer was removed to a
stoneware receiver, also by vacuum. A glass enabled the
operator to avoid drawing oil over with the acid. The pan
was fitted with a thermometer to the interior as well as to
the jacket. For testing the material during reaction,
provision was made for drawing some up by vacuum to a
hydrometer contained in a glass funnel. The final test at
this point read 126° Tw. Another portion could be drawn

up to a test glass and hydrochloric acid passed through it
in full view. A float contained in a glass outer tube served
to show the level of the liquid in the vessel. The pans in
which the operation is carried on, as well as those
employed for washing and distilling the product, were of
a standard pattern employed in many other operations in
the works.
“The washer consisted of a cast iron vessel, lead
lined, and was 2.5 m. in diameter, 2 m. deep, and fitted
with a dome cover and stirring gear. Lead pipes served
for the introduction of sodium carbonate solution and
water. Similar pipes were fitted for drawing these off by
means of a vacuum. A manhole on the cover, with a flat
top, was fitted with light and sight glasses to which were
fitted a small steam coil for keeping them clear. The
washed oil is drawn off to a distillation still, which is a
cast iron vessel homogeneously lead coated, 1.5 m. in
diameter and 2 m. deep, fitted with a lead heating coil
and connected through a spiral lead condenser and
receiver to a vacuum pump. The water is distilled from
the oil at a pressure of from 62 to 70 mm. absolute
pressure. When dried, the oil is sent by vacuum to a
mixing vessel, similar in most respects to the washing
vessel, in which it is mixed with an appointed quantity of
solvent, which, in this factory, was usually chlorobenzene
but occasionally carbon tetrachloride. The relative
quantities varied with the time of year, and instructions
were sent from Berlin on this point. Thence the mixture
was passed to a storage tank and into tank-wagons.”

American Method of Manufacture

The Chemical Warfare Service investigated carefully the three methods
(German, French, and English) and finally adopted the Levinstein process.
The following discussion is taken from a report originally made during
construction, Sept., 1918.

The Levinstein reactor consisted of a jacketed and lead-lined vessel or
steel tank, 8 feet 5 inches in diameter and 14 feet tall. The reactor contained
1,400 feet of lead pipe (outside diameter 2⅜ inches), made up into five
coils, giving a total cooling surface of 1,200 square feet. The finished
charge of such a reactor is 12 tons.
Ethylene was introduced through lead injectors, of which there were 16,
each suspended from its own opening in the top and hanging so that the end
of the injector tube was 12 inches from the bottom of the reactor. The
nozzle of the injector was ³/₁₆ inch outside diameter and ethylene was
introduced through it at 40 pounds pressure.
In starting the reaction, enough sulfur chloride was introduced into the
reactor to cover the central nozzles. Ethylene was now introduced, and as
the reaction proceeded sulfur chloride was added in sufficient quantities to
give a high rate of reaction. Brine or cold water was introduced through the
cooling coils and jacket to keep the reacting temperature at 35° C.
When the charge was completed, the ethylene was turned off so that
only a small amount bubbled through the nozzles and the charge syphoned
off to the settling tank. These were constructed of iron, 8 feet in diameter
and 19 feet tall. They were provided with iron coils by which the liquid may
be cooled down, or the sulfur, which precipitates in the bottom, melted. The
tank was large enough to hold six complete charges of mustard gas and all
the sulfur from these charges was allowed to accumulate before removal of
the sulfur. The supernatant mustard gas was drawn off from above this
sulfur to storage tanks.
Among the factors which influence the reaction are the following:
A temperature of over 60° C. in lead will decompose the product slowly
when sulfur chloride is present.
The presence of iron decomposes the product rapidly at a temperature of
50° C. and probably at a considerably lower temperature.
The purity of the product is dependent upon the time of reaction. There
is always a slow reaction between the mustard gas and sulfur chloride, and
because of this the charge should be completed in 8 hours.
In general the more sulfur that comes out of the solution, the better is
the product. Temperature has a marked effect on the separation of sulfur. In

order to entirely remove the sulfur from the product it was the custom to
increase the temperature at the close of the reaction from 55° to 70° C. This,
however, caused plugging of the lines and the reactor.

Properties

Dichloroethylsulfide (mustard gas) is a colorless, oily liquid, which has
a faint mustard odor. The pure material is said to have an odor very
suggestive of that of water cress. While the odor is more or less
characteristic, it is possible to have extremely dangerous amounts of the gas
in a neighborhood without being detected through its odors. It still seems to
be an open question whether mustard gas paralyzes the sense of smell. One
can find opinions on both sides.
Mustard gas boils at 215°-217° C. at atmospheric pressure, so that it is
at once seen to be a very persistent gas. It distills without decomposition at
this temperature but is best purified by vacuum distillation, or by distillation
with steam. A still for the vacuum distillation of mustard gas has been
described by Streeter.[20]
Mustard gas melts, when pure, at 13° to 14° C. (The ordinary summer
temperature is 20°-25° C.). The ordinary product, as obtained from the
“reactor,” melts from 9°-10° C. In order that the product in the shell might
be liquid at all temperatures, winter as well as summer, the Germans added
from 10 to 30 per cent of chlorobenzene, later using a mixture of
chlorobenzene and nitrobenzene and still later pure nitrobenzene. Carbon
tetrachloride has also been used as a means of lowering the melting point.
Many other mixtures, such as chloropicrin, hydrocyanic acid,
bromoacetone, etc., were tested, but were not used. The effect on the
melting point of mustard gas is shown in the following table:
Melting point of Mustard gas Mixtures
Per Cent Carbon
Chloropicrin Chlorobenzene
Added Tetrachloride
0 13.4° C. 13.4° C. 13.4° C.
10 9.8 8.4 9.8
20 6.3 6.4 6.6

Per Cent Carbon
Chloropicrin Chlorobenzene
Added Tetrachloride
30 2.6 -1.0 3.1
The mustard gas as finally made by the United States contained about
17 to 18 per cent sulfur in solution. The gas was then put in shell and fired
without the addition of any solvent. In actual practice this impure product
seemed even more powerful in causing casualties than equal quantities of
the pure mustard gas. Accordingly no redistilling as originally contemplated
was actually carried out.
The specific gravity of mustard gas at 20° is 1.2741. The solid material
has a slightly higher value, being 1.338 at 13°. Its vapor pressure at room
temperature is very low; at 20° this value has been found to be about 0.06
mm. of mercury.
Mustard gas is practically insoluble in water, less than 0.1 per cent
forming a saturated solution. The reports that a 1 per cent solution could be
obtained did not consider the question of hydrolysis. Mustard gas is freely
soluble in all the ordinary organic solvents, such as ligroin, alcohol, ether,
chloroform, acetic acid, chlorobenzene, etc. In case the solvent is miscible
with water, dilution throws out the product as an oil.

Chemical Properties

Mustard gas is very slowly decomposed by water, owing to its very
slight solubility. The products are dihydroxyethylsulfide and hydrochloric
acid:
(ClCH₂CH₂)₂S + 2H₂O = (HOCH₂CH₂)₂S + 2HCl
Certain sulfonated oils accelerate the rate of hydrolysis, both by
increasing the rate of solution and the solubility of the mustard gas. Alkalies
also increase the rate of hydrolysis. Oxidizing agents destroy mustard gas.
This reaction was made use of practically in that solid bleaching powder
was early introduced as a means of destroying mustard gas in the field. (Fig.
9.)

Chlorinating agents (chlorine, sulfur dichloride, etc.) rapidly transform
mustard gas into an inactive (non-blistering) substance. Sulfur dichloride
was a valuable reagent in both laboratory and works in “cleaning up”
mustard gas. This reaction also explains why the early attempts to prepare
mustard gas by the interaction of ethylene and sulfur dichloride were
unsuccessful. Mustard gas is probably formed, but is almost immediately
chlorinated by the excess of sulfur dichloride. Sulfur chloride on the other
hand has no effect on mustard gas. Chloramine-T and Dichloramine-T (the
valuable therapeutic agents introduced by Dakin and Carrel for treatment of
wounds) also react with mustard gas. For this reason they were advocated
as treatment for mustard gas burns. But as we will see later, they were not
altogether successful.

Detection

At first the only method of detecting mustard gas was through the sense
of smell. It was then believed that concentrations which could not be
detected in this way were harmless. Later this proved not to be the case, and
more delicate methods had to be devised. In the laboratory and in the field
these tests were not very satisfactory, because most of them depended upon
the presence of chlorine, and the majority of the war gases contained
chlorine or one of the other halogens. The Lantern Test depended upon the
accumulation of the halogen upon a copper gauze and the subsequent
heating of the gauze in a Bunsen flame. This test could be made to detect
one part of mustard gas in ten million parts of air. Another field detector
devised by the Chemical Warfare Service consisted in the use of selenious
acid. Here again the lack of specificity is apparent, for while certain
halogen compounds did not give the test, arsine and organic arsenicals gave
a positive reaction and often in a shorter time than mustard gas.

Fig. 36.—Field Detector for Mustard Gas.

The Germans are said to have had plates covered with a yellow
composition which had the property of turning black in the presence of
mustard gas. These plates were lowered into the bottom of recently captured
trenches and if, after a few minutes, they turned black, the presence of
mustard gas was suspected. It is also stated that the characteristic yellow
paint on the olive of the mustard gas shell had the same composition, and
was useful in detecting leaky shell. According to a deserter’s statement,
however, reliance upon this test resulted in casualties in several instances.
A white paint has also been reported which turned red in the presence of
mustard gas. This color change was not characteristic, for tests made by our
Army showed that other oils (aniline, turpentine, linseed) were found to
produce the same effect.
The Chemical Warfare Service was able to develop an enamel and an oil
paint which were very sensitive detectors of mustard gas. Both of these
were yellow and became dark red in contact with mustard gas. The change
was practically instantaneous. The enamel consisted of chrome yellow as
pigment mixed with oil scarlet and another dye, and a lacquer vehicle,
which is essentially a solution of nitrocellulose in amyl acetate. One gallon

of this enamel will cover 946,500 sq. cm., or a surface equivalent to a band
3 cm. wide on 12,500 seven cm. shell.
The paint was composed of a mixture of 50 per cent raw linseed oil and
50 per cent Japan drier, with the above dye mixture added to the required
consistency. In contact with liquid mustard gas, this changes to a deep
crimson in 4 seconds. Furthermore, in contact with arsenicals, this paint
changes to a color varying from deep purple to dark green, the color change
being almost instantaneous and very sensitive, even to the vapors of these
compounds. Other substances have no effect upon the paint.
For field work, however, nothing was found equal to the trained nose,
and it is questionable if any of the mechanical means described will be used
in the field.

Physiological Action

One of the most interesting phases of mustard gas is its peculiar
physiological action. This has been studied extensively, both as relates to
the toxicity and to the skin or blistering effect.

Toxicity

When one considers the high boiling point of mustard gas, and its
consequent low vapor pressure, he is likely to conclude that such a
substance would be of comparatively little value as a toxic or poison gas.
While it is true that an important part of the military value of mustard gas
has been because of its vesicant properties, the fact still remains that it is
one of our most toxic war gases. The following comparison with a few of
the other gases indicates this:
Mg. per Liter
Mice Dogs
Mustard gas 0.2 0.05
Phosgene 0.3 ···
Hydrocyanic acid 0.2 0.1
Chloropicrin 1.5 0.8

Mg. per Liter
Mice Dogs
··· 3.0
When an animal is exposed to the vapors of mustard gas in high
concentration, it subsequently shows a complexity of symptoms, which may
be divided into two classes:
(1) The local effects on the eyes, skin and respiratory tract. These are
well recognized and consist mainly of conjunctivitis and superficial
necrosis of the cornea; hyperemia, œdema and later, necrosis of the skin,
leading to a skin lesion of great chronicity; and congestion and necrosis of
the epithelial lining of the trachea and bronchi.
(2) The systemic effects due to the absorption of the substance into the
blood stream, and its distribution to the various tissues of the body.
The most striking observation about the symptoms of mustard gas
poisoning is the latent period which elapses after exposure before any
serious objective or subjective effects are noted. The developments of the
effects are then quite slow, unless very high superlethal doses have been
inhaled.
At first it was a very serious question whether or not the temporary
blindness resulting from mustard gas would not be permanent. Later, as the
depth and seriousness of some of the body burns became well known, it
was a seven-day wonder that no permanent blindness occurred.
The reason seems to be largely a mechanical one. The constant winking
of the eyelids apparently washes the mustard gas off the eyeball and carries
it away so that not enough remains to burn to the depth necessary to cause
permanent blindness.
Due to the very slight concentrations ordinarily encountered in the field,
resulting from a very slow rate of evaporation, the death rate is very low,
probably under 1 per cent among the Americans gassed with mustard during
the war.
If, on the other hand, the gas be widely and very finely dispersed by a
heavy charge of explosive in the shell, the gas is very deadly. In such cases
the injured breathe in minute particles of the liquid and thus get hundreds of

times the amount of gas that would be inhaled as vapor. This so-called
“high explosive mustard gas shell” was a German development in the very
last months of the war. Its effects were great enough to make it certain that
in the future large numbers of these shell will be used.
The similarity of the symptoms and pathological effects after the
inhalation of large amounts of the vapor and those following an injection of
an olive oil or water solution of mustard gas led Marshall and his associates
to conclude that in high concentrations mustard gas is absorbed through the
lungs. A further bit of evidence consists in the isolation of the hydrolysis
product, dihydroxyethylsulfide, in the urine of animals poisoned by
inhalation of mustard gas. This product is not toxic and is not responsible
for the effects of mustard gas. Hydrochloric acid, however, does produce
very definite effects upon the animal and may cause death.
From these facts Marshall[21] has proposed the following mechanism of
the action of mustard gas:
“Dichlorethylsulphide is very slightly soluble in
water and very freely soluble in organic solvents, or has a
high lipoid solubility or partition coefficient. It would,
therefore, be expected to penetrate cells very readily. Its
rapid powers of penetration are practically proven by its
effects upon the skin. Having penetrated within the living
cell, it would undoubtedly hydrolyze. The liberation of
free hydrochloric acid within the cell would produce
serious effects and might account for the actions of
dichlorethylsulphide. To summarize, then, the mechanism
of the action of dichlorethylsulphide appears to be as
follows:
“1. Rapid penetration of the substance into the cell by
virtue of its high lipoid solubility.
2. Hydrolysis by the water within the cell, to form
hydrochloric acid and dihydroxyethylsulphide.
3. The destructive effect of hydrochloric acid upon
some part or mechanism of the cell.

“Although hydrochloric acid does not penetrate cells
readily and is easily neutralized by the buffer action of
the fluids of the body, we might expect by flooding the
body with large quantities of acid to produce some of the
characteristic effects of mustard gas. Stimulation of the
respiratory center is a well known effect of acid.
Convulsions and salivation may be produced by injection
of hydrochloric acid and we have been able to produce
slowing of the heart by rapid injection of this acid.
“The delayed action of mustard gas might be
explained by the formation of some compound with some
constituent of the blood. However, blood taken from dogs
which had been poisoned with mustard gas and were
exhibiting typical symptoms at the time, injected into
normal dogs produced no effect. Serum treated in vitro
with mustard gas and allowed to stand and then injected
into a dog, produced no effect. The fluid which is formed
in the vesicle and blebs produced by the application of
mustard gas to the skin produces no mustard gas effects.”
In studying the toxicity of mustard gas for dogs, it was observed that a
concentration of 0.01 mg. per liter could be tolerated indefinitely. If this
value is considered as a threshold value, and subtracted from the toxicity
values for varying periods of time, it is found that there is a definite relation
between the toxic concentration and the time of exposure. This is expressed
by the formula
(C - 0.01)t = K
where C is the concentration observed for a given time t. K has the
approximate value of 1.7, where t varies between 7.5 and 480 minutes.

Vesicant Action

In addition to its toxicity mustard gas is highly important because of its
peculiar irritating effect upon the skin. Its value is seen when we realize that
one part in 14,000,000 is capable of causing conjunctivitis of the eye and
that one part in 3,000,000 and possibly one part in 5,000,000 will cause a

skin burn in a sensitive person on prolonged exposure. According to
Warthin, the lesions produced by mustard gas are those of a chemical, not
unlike hydrochloric acid, but of much greater intensity. The pathology of
these lesions has been carefully studied and fully described by Warthin and
Weller in their book on The Pathology of Mustard Gas. Our observations
will therefore be confined to certain striking features of the vesicant action
of this substance.

Variation in Susceptibility of the Skin

Every worker who has worked with mustard gas has noticed that some
individuals are much more susceptible to skin burns from this substance
than are others. Marshall made a study of 1282 men at Edgewood Arsenal,
using a 1 per cent and a 0.01 per cent solution of mustard gas in paraffin oil.
A small drop of these solutions was applied to the skin of the forearm of the
subject and the arm allowed to remain uncovered for about 10 minutes. The
presence or absence of a positive reaction is indicated by the appearance or
absence of erythema 24 hours later. The results were as follows:
1% 0.01% % of Total
Positive Positive 3.3
Positive Negative 55.3
Negative Negative 41.4
The test made on 84 negroes gave the following results:
1% 0.01% % of Total
Positive Positive 0.0
Positive Negative 15.0
Negative Negative 78.0
Questionable Negative 7.0
“It is seen from the above tables that negroes as a
race, have a much more resistant skin than white men. No
negro of the 84 examined reacted to the 0.1 per cent
solution, and of course none would react to a more dilute
one. About 10 per cent of white men react to the 0.1 per
cent solution, while 2 to 3 per cent react to the 0.01 per

cent solution or are hypersensitive. About 78 per cent of
the negroes fail to react to the 1 per cent solution, while
only 20 to 40 per cent of the white race do not show a
reaction.”

Fig. 37.

The same individual may also show variations in susceptibility and this
has also been studied by Marshall.
“The effect of exercise and sweating was
investigated. A number of individuals were given vapor
burns (one to five minutes exposure) and then exercised
until in a profuse sweat, and then the same exposure to
vapors made. In all cases the burn produced after
exercising was more severe. Sweating produced by
having the subjects place their feet in hot water, produced

the same increase in susceptibility. That the moisture on
the skin produced by sweating is at least partly, if not
entirely, responsible for the increased susceptibility, was
shown in the following way: An area of the forearm was
kept moist for a few minutes with wet cotton. The sponge
was then removed and two vapor tests made, one over the
moist area and one over normal, dry skin. In all cases the
moist burn was the more severe, in one, producing a
blister where the control did not.
“The skin of different areas of the body is
undoubtedly somewhat different in its susceptibility. All
our tests have been applied to the forearm. The hands are
considerably more resistant than the forearm. Tests made
by the oil method on the forearm, chest, and back,
however, indicate very little difference in susceptibility of
these areas. The skin in the neighborhood of old burns
has been shown to be more susceptible.
“In general, the same individual does not become
more susceptible to skin burns from continued exposure
to the vapor. The great number of tests which have been
made on the same individual at different times and under
the same conditions, indicate a remarkable constancy in
reaction. A series of men who were tested at various
times during a period of four months, revealed slight
changes from time to time in some of the men. No man
who originally reacted to only the 1 per cent solution ever
reacted to the 0.01, and likewise, no man who originally
reacted to the 0.01 ever failed to react to the 0.1 per cent.
“Susceptibility of skin of animals. The paraffin oil test
was used on a number of animals and indicated that
differences in susceptibility exist in different species and
in different individuals of the same species.”

Percentage Positive to
Number
Species 1 Per 0.1 Per 0.01 Per
Tested
Cent Cent Cent
Horse 1 100 100 100
Dog 91 83 35 0
Goat 11 55 36 0
Rat 10 30 20 0
Mouse 7 70 14 0
Rabbit 2 100 0 0
Guinea-pig 12 33 0 0
Monkey 9 22 0 0
The horse appears to be the most sensitive and the monkey and guinea-
pig the most resistant species, while the dog would seem to have a
sensitivity as near man as any of the species studied. No animal has yet
been found which will give a blister from the application of mustard gas.
Smith, Clowes and Marshall[22] have studied the mechanism of
absorption by the skin. They find that it is quite evident that the mustard gas
is at first rapidly taken up by some element on, or adjacent to, the surface of
the skin and for two to three minutes it may be completely removed, and for
ten to fifteen minutes partially removed by prolonged washing With an
organic solvent, and to a lesser extent with soap and water.
An interesting phenomenon is observed when the untreated normal skin
of one subject is impressed for five minutes upon an area of skin of another
subject, which has been exposed previously to the vapors of mustard gas.
Under these circumstances both donor and recipient may develop burns
(due to the transposition of the poison from one skin to another), the
intensity of which will vary according to the circumstances and the
respective sensitiveness of the participants. The degree of transposition is
most strikingly observed in the intensity of the burn on the donor’s arm. If
two similar exposures are made on the arm of a sensitive man, and one of
these burns is treated, so to speak, by contact for five minutes, with the skin
of a resistant man, the treated burn will be markedly less severe than the
control, in some cases being entirely prevented. If, however, the recipient is
equally sensitive to or more sensitive than the donor, the burns on the latter

will exhibit far less difference. Both treatments may be effected at once,
using two recipients, one more, and the other less, resistant than the donor.
In such a case the burn brought into contact with the more resistant skin
will be the less severe.
Similarly, if a sensitive individual impresses his arm alternately against
burns of the same concentration and exposure on a resistant and sensitive
man, the recipient receives a more severe burn from the sensitive than from
the resistant man.
This indicates that the skin of a resistant individual exhibits a greater
affinity or capacity for mustard gas than that of a sensitive one. There is an
actual partition of the gas between the two skins, with an evident tendency
to establish an equilibrium in which the larger portion of the gas will remain
in that skin which possesses the greater capacity for it.
“A tentative explanation of this phenomenon can be
made as follows. A three phase system is involved—the
air over the skin surface constitutes the outer phase; some
fatty or keratinous elements of the skin, the central phase;
and a cellular portion of the skin the inner phase. The
central phase is rich in lipoids and poor in water, while
the inner phase is rich in water and poor in lipoids. After
exposure to the vapors of dichloroethylsulphide the
central phase is the absorbing agent and tends to establish
equilibrium with the other two phases. On account of the
lipoid nature of the central phase no damage is produced
here because the compound is not hydrolyzed. On its
passage from the central to the inner phase hydrolysis
takes place within the cell and damage results when a
sufficient concentration of hydrochloric acid is attained.
The outer phase is constantly being freed from vapor by
diffusion and convection currents, so more and more can
evaporate from the central phase. The susceptibility of an
individual depends on the relative power of the central
phase to hold the poison in an inactive form (not
hydrolyzed) and prevent its entry into the inner phase at a
sufficient velocity to result in the formation of a toxic
concentration. We do not attempt to localize the central or

inner phases with any definite structure of the skin. As
mustard is known to penetrate the sebaceous ducts the fat
here might form one phase and the epithelial lining
another.”

Tactical Use of Mustard Gas

As before stated, mustard gas, like most other materials used in war,
was discovered in peace. Indeed, Victor Meyer in 1886 worked out fairly
completely its dangerous characteristics. Like phosgene and chlorine used
before it, the materials for its production were available in considerable
quantities through the manufacture of components either for dyes or
photographic chemicals.
Mustard gas, besides being highly poisonous, has so many other
important qualities as to have given it the designation during the war of the
“king of gases.” That broad distinction it still holds. Its introduction at
Ypres, on the night of July 12, 1917, changed completely the whole aspect
of gas warfare and to a considerable extent the whole aspect of warfare of
every kind. It is highly poisonous, being in that respect one of the most
useful of all war gases. It produces no immediate discomfort. It has a
considerable delay action. It burns the body inside or out, wherever there is
moisture. Eyes, lungs and soft parts of the body are readily attacked. It
lingers for two or three days in the warmest weather, while in cold, damp
weather it is dangerous for a week or ten days, and in still colder weather
may be dangerous for a month or longer whenever the weather warms up
sufficient to volatilize the liquid. It is only slowly destroyed in the earth,
making digging around shell holes dangerous for weeks and months and in
some cases possibly a year or more.
The Germans first used it simply to get casualties and interfere with or
break up the threatened heavy attacks by the British on the Ypres salient.
While not stopping the inauguration of these attacks in the fall of 1917, the
German use of mustard gas was so effective as to delay the beginning of
those attacks for at least two weeks and thus gain valuable time for the
Germans, besides causing serious casualties with consequent partial break
up of companies, regiments and divisions in the English Army.

The German used his mustard gas throughout the fall of 1917 and the
winter of 1917 and 1918, as above stated, to produce casualties, to destroy
morale, to break up units, and to interfere with operations generally. During
that time, however, he developed a more scientific use and when he started
his big offensives in March, April, May and June, 1918, he used mustard
gas before the battles to cause losses, break up units and destroy morale,
and also during the progress of battles to completely neutralize strong
points which he felt he did not want to attempt to take by direct assault.
Perhaps the most noted case of this was at Armentières in April, when he
deluged the city to such an extent that mustard gas is said to have actually
run in the streets. So effective was this gassing that not only did the British
have to withdraw from the city but the Germans could not enter it for more
than two weeks. It, however, enabled the Germans to take the city with
practically no loss of life. There were numerous other cases on a smaller
scale where mustard gas was used in the same way.
On account of its persistence it has been generally referred to as a
defensive gas and for that purpose it is incomparable. The use of sufficient
quantities of mustard gas will almost certainly stop the occupation of areas
by the enemy and probably even stop his crossing them. It also enables
strong points which it is not desired to attack to be completely neutralized,
—that is, made so unhabitable that the area must be evacuated.
A use that was proposed toward the end of the war, and that will
undoubtedly be made of the gas in the future, is to have it planted in drums
in the ground and exploded when an enemy is attempting to advance. This
would be a highly economic way to distribute great quantities of the
material at the moment and in the place most heeded. It has even been
proposed, and this would seem entirely feasible, to sprinkle certain of these
areas with mustard gas by means of sprinklers attached to drums or even
tanks mounted on trucks.
Just before the Armistice the German made another development in the
use of mustard gas. Instead of the ordinary amount of explosive, which only
fairly opened up the shell and allowed the liquid to escape, he filled nearly
30 per cent of the total space of the shell with high explosive. This
completely broke up the shell and distributed the greater part of the liquid
mustard gas in the form of a fine spray. This spray, when breathed, proved
extremely deadly, as might be expected from the fact that when in the form

of minute particles one can draw into the lungs in a single breath one
hundred times or more the amount that he would get of pure gas.
Since mustard gas has such a delay action and is effective in such small
concentrations it can be used very effectively in small calibre guns, as the
75 mm. or 3-inch. Furthermore, since it lasts for two or three days at the
very least, a small number of guns can keep a very large area neutralized
with the gas. With phosgene and similar non-persistent gases that volatilize
almost completely upon the burst of the shell it is necessary to build up a
high concentration immediately. The exact opposite is true of mustard gas.
Mustard gas can be fired very slowly with the certain knowledge that all
shells fired at one moment will be effective when the next is fired, though
twelve hours or more may intervene between the first and last firing. Thus,
while with phosgene a large number of guns are needed for a gas attack,
with mustard gas the number can be reduced to one-tenth or even less.
Mustard gas may be in the future and has been in the past used safely in
hand grenades because of its very low vapor tension, whereby the pressure
at ordinary temperatures is exceedingly low. This has an important bearing
on cylinders and other containers for shipping mustard gas, that is, they
need be only strong enough to be safe against handling and not to withstand
the high pressure encountered with phosgene or chlorine cylinders.
In the future, mustard gas will be used in all the ways above stated and
undoubtedly in many more. It can be fired in large quantities upon strong
points to force their evacuation. It can be fired on the flank of attacking
armies for protection against counter-attacks. It can be fired against the
enemy artillery at all times to silence them and stop their firing. It was thus
used by the Americans in the Argonne against the enemy on the east bank of
the Meuse River, this river separating the American and German armies. It
was extremely effective in stopping the enemy’s artillery. The high
explosive mustard gas shell, not only because of its persistency but because
of its quick deadliness, can be fired singly and be depended upon to do its
work wherever there be men or animals. One of the greatest uses will be by
simple sprinkling from aeroplanes.
The future will see mustard gas used at nearly all times with a certain
quantity of a powerful lachrymator or tear gas. This is for the reasons, as
stated in the beginning, that mustard gas causes no immediate discomfort
and has no objectionable smell. Accordingly, if the battle be critical, men

may continue to fight from four to eight hours in a mustard gas atmosphere
without masks. It is true the casualties will be high with a high death rate.
Nevertheless, this period of time might enable the artillery to do such
effective work as to completely stop an attack. If, however, at the instant
mustard gas firing is begun a number of powerful lachrymatory shells are
sent over, the immediate wearing of the mask is forced. The enemy is then
subject to all the burning effects of mustard gas as well as the discomfort of
long wearing of the mask.
It may confidently be expected that further developments in the use of
mustard gas will be made, as well as further developments in methods of
throwing it upon the enemy or of bursting shell containing it in his midst.

CHAPTER X
ARSENIC DERIVATIVES
Since arsenic is well known as an insecticide in the form of lead
arsenate, arsenic acid etc., and in pharmacy, specially in the form of
salvarsan and neosalvarsan, it is not surprising that the Germans should
have endeavored to discover an arsenic derivative which would be of value
from the point of view of chemical warfare. Very early in the war persistent
rumors were circulated that the Germans were to use arsine. These rumors
led to the use of sodium permanganate in the canister, but as far as is
known, no arsine was actually used. Another suggestion which received
considerable attention from American workers was the use of arsenides,
which might decompose under the influence of the atmospheric moisture
with the liberation of arsine. Calculation of the amount of arsenide
necessary to establish a lethal concentration of arsine showed, however, that
there was no possibility of using the material on the field.
Because of the use of arsenic trichloride in the manufacture of organic
arsenic compounds, a method of preparation was developed from arsenic
trioxide and sulfur chloride or hydrogen chloride. It was also shown
experimentally that the phosgene of the tail gas of phosgene plants might be
converted into arsenic trichloride by reaction with arsenic trioxide.
Charcoal is the catalyzer of this reaction.
Arsenic trichloride is also of interest because it was one of the
constituents of the mixture vincennite, early used by the French. This was a
mixture of hydrocyanic acid, stannic chloride, arsenic trichloride and
chloroform. While extensively used at first, it was gradually replaced by
phosgene.
Arsenic triflouride was also prepared by the action of sulfuric acid upon
a mixture of calcium flouride and arsenic trioxide. The compound is very
easily decomposed by the moisture of the air, and furthermore is not very
toxic.

Organic arsenic derivatives are the most important compounds from the
military point of view. The first substance used was diphylchloroarsine, a
white solid, which readily penetrated the canister and caused sneezing. This
was used alone, and in solution in phenyl dichloroarsine. Later methyl and
ethyl dichloroarsines were introduced.

Fig. 38.—Apparatus for the Manufacture of
Methyldichloroarsine.

Methyldichloroarsine

The Germans apparently used ethyldichloroarsine because they had no
suitable method for the preparation of methyl dichloroarsine, which is a
more satisfactory material. The Chemical Warfare Service developed the
following method of preparation of the methyl derivative. Sodium arsenite

(Na₃AsO₃) is prepared by dissolving arsenic trioxide in sodium hydroxide
solution. The action of methyl sulfate at 850 C. gives disodium methyl
arsenite, Na₂CH₃AsO₃. Sulfur dioxide reduces the arsenite to methyl arsine
oxide, CH₃AsO, which is then reacted with hydrochloric acid to give
methyl dichloroarsine. The final product is distilled from the mixture and
condensed. This material costs from two to two and a half dollars per pound
for chemicals (war prices).
Methyldichloroarsine is a colorless liquid of powerful burning odor,
which boils at 132° C. It is somewhat soluble in water and is soluble in
organic solvents. The specific gravity is 1.838 at 20° C. The vapor pressure
at 25° was found to be 10.83 mm. mercury. Not only is the material toxic
but it has remarkable vesicant properties, comparing favorably with
mustard gas in this respect.
Ethyldichloroarsine, which was used by the Germans, was prepared by
the method given above, using ethyl sulfate, but the yield was never over 20
per cent. In general this has properties similar to the methyl derivative.

Diphenylchloroarsine

The best known of the arsenicals, however, is diphenylchloroarsine or
sneezing gas. Although this is an old compound (having been prepared by
German chemists in 1885), there was no method for its preparation on a
large scale when, first introduced into chemical warfare. It was finally
discovered that the interaction of triphenyl arsine with arsenic trichloride
was fairly satisfactory and a plant was erected for its manufacture.
When pure, diphenylchloroarsine is a colorless solid, melting at 44°.
Because of this, it was always used in solution in a toxic gas or in a shell
which contained a large amount of explosive so that on the opening of the
shell the material would be finely divided and scattered over a wide
territory.
Its value lay in the fact that the fine particles readily penetrated the
ordinary mask and caused the irritation of the nose and throat, which
resulted in sneezing. This necessitated the perfection of special smoke
filters to remove the particles, after which the other toxic materials were
removed by the absorbent in the canister.

It causes sneezing and severe burning sensations in the nose, throat and
lungs in concentrations as slight as 1 part in 10 million. In higher
concentrations, say 1 in 200 to 500 thousand it causes severe vomiting.
While neither of these effects are dangerous or very lasting, still higher
concentrations are serious, as in equal concentrations diphenylchloroarsine
is more poisonous than phosgene.
Various other arsenical chemicals were developed in the laboratory, but
with one or two exceptions they were not as valuable as
diphenylchloroarsine and methyldichloroarsine and were therefore
discarded.

German Methods for Manufacturing
Arsenicals[23]

Diphenylchloroarsine

“This substance (Blue Cross) was a famous gas of the
Germans and was made in large quantities. The method
used by the Germans was different from the one worked
out by the Allies, and on account of the fact that the
German method could be carried out without specially
designed apparatus and required as raw materials
substances readily obtainable, it was probably preferable.
It is doubtful, however, whether the Allies would have
made this gas, for as the result of its use no fatalities were
reported. The German process consisted in preparing
phenylarsenic acid by condensing benzene diazonium
chloride with sodium arsenite. The acid was next reduced
by sulfur dioxide to phenylarsenous acid, which was, in
turn, condensed with the diazonium compound to form
diphenylarsenic acid. This acid was reduced to
diphenylarsenous oxide, which with hydrochloric acid
yielded diphenylchloroarsine. The chemical equations for
the reactions will make clearer the steps involved.

= C₆H₅AsO₃Na₂ + NaCl
C₆H₅N₂Cl + Na₃AsO₃
+ N₂
C₆H₅AsO₃Na₂ + 2HCl = C₆H₅AsO₃H₂ + 2NaCl
C₆H₅AsO₃H₂ +
= C₆H₅AsO₂H₂ + H₂SO₄
SO₂+H₂O
C₆H₅N₂Cl + (C₆H₅)₂AsO₂Na +
=
C₆H₅AsO₂Na₂ NaCl + N₂
(C₆H₅)₂AsO₂Na + HCl = (C₆H₅)₂AsO₂H + NaCl
2(C₆H₅)₂AsO₂H + 2SO₂ [(C₆H₅)₂As]₂O +
=
+ H₂O 2H₂SO₄
[(C₆H₅)₂As]₂O + 2HCl = 2(C₆H₅)₂AsCl + H₂O.
“The entire process was carried out at Höchst. The
method used at Höchst was as follows: In preparing the
diazonium solution, 3 kg.-mols of aniline were dissolved
in 3000 liters of water and the theoretical quantity of
hydrochloric acid. The temperature of the solution was
reduced to between 0° and 5° and the theoretical amount
of sodium nitrite added. The reaction was carried out in a
wooden tank of the usual form for the preparation of
diazonium compounds. A solution of sodium arsenite was
prepared which contained 20 per cent excess of oxide
over that required to react with the aniline used. The
arsenous oxide was dissolved in sodium carbonate, care
being taken to have enough of the alkali present to
neutralize all of the acid present in the solution of the
diazonium salt. To the solution of the sodium arsenite
were added 20 kg. of copper sulfate dissolved in water,
this being the amount required when 3 kg.-mols of
aniline are used. The solution of the diazonium
compound was allowed to flow slowly into the solution
of the arsenite while the temperature was maintained at
15°. The mixture was constantly stirred during the
addition which requires about 3 hrs. After the reaction
was complete, the material was passed through a filter
press in order to remove the coupling agent and the tar

which had been formed. Hydrochloric acid was next
added to the clear solution to precipitate phenylarsenic
acid, the last portions of which were removed by the
addition of salt.
“The phenylarsenic acid was next reduced to
phenylarsenous acid by means of a solution of sodium
bisulfite, about 20 per cent excess of the latter over the
theoretical amount being used. For 100 parts of arsenic
acid, 400 parts of solution were used. The reaction was
carried out in a wooden vessel and the mixture stirred
during the entire operation. A temperature of 80° was
maintained by means of a steam coil. Phenylarsenous
acid separated as an oil. The aqueous solution was
decanted from the oil, which was dissolved in a solution
of sodium hydroxide, 40° Bé. The solution of the sodium
salt of phenylarsenous acid was treated with water so that
the resulting solution had a volume of 6 cu. m. when 3
kg.-mols of the salt were present. Ice was next added to
reduce the temperature to 15° and a solution of benzene
diazonium chloride, prepared in the manner described for
the first operation, was slowly added. After the coupling,
diphenylarsenic acid was precipitated by means of
hydrochloric acid. The acid was removed by means of a
filter press and dissolved in hydrochloric acid, 20° Bé.
For one part of diphenylarsenic acid, 3 parts of
hydrochloric acid were used. Into this solution was
passed 5 per cent excess of sulfur dioxide over that
required for the reduction. The sulfur dioxide used was
obtained from cylinders which contained it in liquid
condition.
“The reduction was carried out in an iron tank lined
with tiles and a temperature of 80° was maintained.
About 8 hrs. were required for the reaction. The
diphenylarsenic acid on reduction by the sulfur dioxide
was converted into diphenylarsenous oxide which, in the
presence of the hydrochloric acid, was converted into

diphenylchloroarsine, which separated as an oil. The oil
was next removed and heated in the best vacuum
obtainable until it was dry and free from hydrochloric
acid. The compound melted at 34°. It was placed in iron
tanks for shipment. The yield of diphenylchloroarsine
calculated from the aniline used was from 25 to 30 per
cent of the theoretical. No marked trouble was observed
in handling the materials and no serious poisoning cases
were reported.

Diphenylcyanoarsine

“This compound was prepared by treating diphenylchloroarsine with a
saturated aqueous solution of potassium or sodium cyanide.
(C₆H₅)₂AsCl + NaCN = (C₆H₅)₂AsCN + NaCl.
Five per cent excess of the alkaline cyanide was used. The reaction was
carried out at 60° with vigorous stirring. The yield was nearly theoretical.

Ethyldichloroarsine

“This compound was prepared at Höchst from ethylarsenous oxide
which was obtained from the Badische Anilin und Soda Fabrik.
“Preparation of Ethylarsenous Oxide—The compound was prepared
by treating sodium arsenite with ethyl chloride under pressure. The
resulting sodium salt of ethylarsenic acid was converted into the free acid
and reduced by sulfur dioxide. The ethylarsenous acid formed in this way
lost water and was thereby transformed into ethylarsenous oxide. The
reactions involved are as follows:
C₂H₅Cl + Na₃AsO₃ = C₂H₅AsO₃Na₂ + NaCl
C₂H₅AsO₃Na₂ + 2 HCl = C₂H₅AsO₃H₂ + 2 NaCl
C₂H₅AsO₃H₂ + SO₂ + H₂O = C₂H₅AsO₂H₂ + H₂SO₄
2C₂H₅AsO₂H₂ = (C₂H₅As)₂O + H₂O.

“The ethyl chloride used in the preparation was in part made in this
factory, and in part received from other sources. As ethyl chloride is an
important product used in peace time, it is not, therefore, essentially a war
product and its preparation was not described.
“In preparing the solution of sodium arsenite, one molecular weight of
arsenous oxide was dissolved in a solution containing 8 molecular weights
of sodium hydroxide. The solution of the base was prepared from a 50 per
cent solution of sodium hydroxide to which enough solid alkali was added
to make the solution a 55 per cent one. In one operation 660 kg. of arsenous
oxide were used. For 100 parts of arsenous oxide, 130 parts of ethyl
chloride were used, this being the theoretical amount of the latter.
“The reaction was carried out in a steel autoclave of about 300 liters
capacity. The temperature was maintained at between 90° and 95°. The
ethyl chloride was pumped in, in 3 or 4 portions, and the pressure in the
autoclave was kept at from 10 to 15 atmospheres. The several portions of
ethyl chloride were introduced at intervals of about 1½ hrs. During the
entire reaction, the contents of the autoclave were vigorously stirred. After
all the ethyl chloride had been added, the material was stirred from 12 to 16
hrs., at the end of which time the pressure had fallen to about 6
atmospheres. The excess of ethyl chloride and the alcohol formed in the
reaction were next distilled off. At this point a sample of the solution was
drawn off for testing. This was done by determining the amount of arsenite
present in the solution. If not more than 20 per cent of sodium arsenite had
not reacted, the preparation was considered satisfactory. Water was then
added to the contents of the autoclave in sufficient amount to dissolve the
solid material. The product was next drawn over into a tank and neutralized
with sulfuric acid. It was then treated with sulfur dioxide gas until there was
an excess of the latter present. The mixture was then heated to about 70°
when the ethylarsenous oxide precipitated as a heavy oil. This was readily
separated and shipped without further purification. The yield of
ethylarsenous oxide, from arsenic oxide, was from 80 to 82 per cent of a
product which contained about 93 per cent of pure ethylarsenous oxide.
“Preparation of Ethyldichloroarsine—The compound was prepared
by treating ethylarsenous oxide with hydrochloric acid. The reaction is as
follows:

C₂H₅AsO + 2HCl = C₂H₅AsCl + H₂O.
The operation was carried out in an iron kettle lined with lead, which
was cooled externally by means of water and which was furnished with a
lead covered stirrer. To the kettle, which contained from 500 to 1000 kg. of
hydrochloric acid left over from the previous operation, were added 4000
kg. of ethylarsenous oxide. The gaseous hydrochloric acid was next led in.
The kettle was kept under slightly diminished pressure in order to assist in
the introduction of hydrochloric acid. The temperature during the reaction
must not rise above 95°. When the hydrochloric acid was no longer
absorbed and was contained in appreciable quantities in the issuing gases,
the operation was stopped. This usually occurred at the end of from one to
two days. The product of the reaction was drawn off by means of a water
pump and heated in a vacuum until drops of oil passed over. The residue
was passed over to a measuring tank and finally to tank-wagons made of
iron. The yield of the product was practically the theoretical.
On account of the volatility of the compound and its poisonous
character, the apparatus in which it was prepared was surrounded by an
octagonal box, the sides of which were fitted with glass windows. Through
this chamber a constant supply of air was drawn. This was led into a
chimney where the poisonous vapors were burned. The gases given off
during the distillation of the product were passed through a water scrubber.”

“Lewisite”

The one arsenical which created the most discussion during the War,
and about which many wild stories were circulated, was “Lewisite,” or as
the press called it, “Methyl.” Its discovery and perfection illustrate the
possibilities of research as applied to Chemical Warfare, and points to the
need of a permanent organization to carry on such work when the pressure
of the situation does not demand such immediate results.
The reaction of ethylene and sulfur chloride, which led to the
preparation of mustard gas, naturally led the organic chemists to investigate
the reaction of this gas and other unsaturated hydrocarbons, such as
acetylene, upon other inorganic chlorides, such as arsenic, antimony and tin.
There was little absorption of the gas, either at atmospheric or higher

pressures, and upon distilling the reaction product, most of the gas was
evolved, showing that no chemical reaction had taken place. However,
when a catalyser, in the form of aluminium chloride, was added, Capt.
Lewis found that there was a vigorous reaction and that a highly vesicant
product was formed. The possibilities of this compound were immediately
recognized and the greatest secrecy was maintained regarding all the details
of preparation and of the properties of this new product. At the close of the
War, this was considered one of the most valuable of Chemical Warfare
secrets, and therefore publication of the reactions involved were withheld.
Unfortunately or otherwise, the British later decided to release the material
for publication, and details may be found in an article by Green and Price in
the Journal of the Chemical Society for April, 1921. It must be emphasized
that the credit for this work belongs, not to these authors, but to Capt. W.
Lee Lewis and the men who worked with him at the Catholic University
branch of the American University Division (the Research Division of the
C. W. S.).
On a laboratory scale, acetylene is bubbled through a mixture of 440
grams of anhydrous arsenic trichloride and 300 grams of anhydrous
aluminium chloride. Absorption is rapid and much heat is developed. After
six hours, about 100 grams of acetylene is absorbed. The reaction product
was dark colored and viscid, and had developed a very powerful odor,
suggestive of pelargoniums. Attempts to distill this product always led to
violent explosions. (It may be stated here that Lewis was able to perfect a
method of distillation and separation of the products formed, so that pure
materials could be obtained, with little or no danger of explosion.) The
English chemists therefore decomposed the product with ice-cold
hydrochloric acid solution of constant boiling point (this suggestion was the
result of work done by Lewis). The resulting oil was then distilled in a
current of vapor obtained from constant boiling hydrochloric acid and
finally fractionated into three parts.
The first product obtained consist in the addition of one acetylene to the
arsenic trichloride molecule, and, chemically, is chlorovinyldichloroarsine,
CHCl: CH·AsCl₂, a colorless or faintly yellow liquid, boiling at 93° at a
pressure of 26 mm. A small quantity, even in very dilute solution, applied to
the skin causes painful blistering, its virulence in this respect approaching
that of mustard gas. It is more valuable than mustard gas, however, in that it

is absorbed through the skin, and as stated on page 23, three drops, placed
on the abdomen of a rat, will cause death in from one to three hours. It is
also a very powerful respiratory irritant, the mucous membrane of the nose
being attacked and violent sneezing induced. More prolonged exposure
leads to severe pain in the throat and chest.
The second fraction (β, β′-dichlorodivinylchloroarsine) is a product
resulting from the addition of two acetylene molecules to one arsenic
trichloride, and boils at 130° to 133° at 26 mm. It is much less powerful as a
vesicant than chlorovinyldichloroarsine, but its irritant properties on the
respiratory system are much more intense.
The third fraction, β, β′, β″-trichlorotrivinylarsine, (CHCl: CH)₃As, is
a colorless liquid, boiling at 151° to 155° at 28 mm., which solidifies at 3°
to 4°. It is neither a strong vesicating agent nor a powerful respiratory
irritant. At the same time, its odor is pungent and most unpleasant and it
induces violent sneezing.

CHAPTER XI
CARBON MONOXIDE
Carbon monoxide, because of its cheapness, accessibility and ease of
manufacture, has been frequently considered as a possible war gas.
Actually, it appears never to have been used intentionally for such purposes.
There are several reasons for this. First, its temperature of liquefaction at
atmospheric pressure is -139° C. This means too high a pressure in the
bomb or shell at ordinary temperatures. Secondly, the weight of carbon
monoxide is only slightly less than that of air, which keeps it from rolling
into depressions, dugouts and trenches, as in the case of ordinary gases, and
also permits of its rather rapid rise and dissipation into the surrounding
atmosphere. A third reason is its comparatively low toxic value, which is
only about one-fifth that of phosgene. However, as it can be breathed
without any discomfort, and as it has some delay action, its lack of
poisonous properties would not seriously militate against its use were it not
for the other reasons given.
It is, nevertheless, a source of serious danger both in marine and land
warfare. Defective ventilation in the boiler rooms of ships and fires below
decks, both in and out of action, are especially dangerous because of the
carbon monoxide which is produced. In one of the naval engagements
between the Germans and the English, defective high explosive shell, after
penetrating into enclosed portions of the ship, evolved large quantities of
carbon monoxide and thus killed some hundreds of men. On shore, machine
gun fire in enclosed spaces, such as pill boxes, and in tanks, liberates
relatively large quantities of carbon monoxide. Similarly, in mining and
sapping work, the carbon monoxide liberated by the detonation of high
explosives constitutes one of the most serious of the difficulties connected
with this work and necessitated elaborate equipment and extensive military
training in mine rescue work.
The removal of carbon monoxide from the air is difficult because of its
physical and chemical properties. Its low boiling point and critical
temperature makes adequate adsorption at ordinary temperatures by the use

of an active absorbent out of the question. Its known insolubility in all
solvents similarly precludes its removal by physical absorption.
After extensive investigation two absorbents have been found.[24] The
first of these consists in a mixture of iodine pentoxide and fuming sulfuric
acid, with pumice stone as a carrier. Using a layer 10 cm. deep and passing
a 1 per cent carbon monoxide air mixture at the rate of 500 cc. per minute
per sq. cm. cross section, a 100%-90% removal of the gas could be secured
for two hours at room temperature and almost as long at 0° C. The reaction
is not instantaneous, and a brief induction period always occurs. This may
be reduced to a minimum by the addition of a little iodine to the original
mixture.
The sulfur trioxide given off is very irritating to the lungs, but by the
use of a layer of active charcoal beyond the carbon monoxide absorbent,
this disadvantage was almost completely eliminated. However, sulfur
dioxide is slowly formed as a result of this adsorption and after prolonged
standing or long-continued use of the canister at a high rate of gas flow
gives serious trouble.
Considerable heat is given off in the reaction and a cooling attachment
was required. The most satisfactory device was a metal box filled with
fused sodium thiosulfate pentahydrate, which absorbed a very considerable
amount of the heat.
Still a further disadvantage was the fact that the adsorbents became
spent by use, even in the absence of carbon monoxide, since it absorbed
enough moisture from the air of average humidity in several hours, to
destroy its activity.
The difficulties mentioned were so troublesome that this absorbent was
finally supplanted by the more satisfactory oxide absorbent described
below.

Fig. 39.—Diagram of Carbon Monoxide Canister, CMA3.

The metallic oxide mixture was the direct result of an observation that
specially precipitated copper oxide with 1 per cent silver oxide was an
efficient catalyst for the oxidation of arsine by oxygen. After a study of
various oxide mixtures, it was found that a mixture of manganese dioxide
and silver oxide, or a three component system containing cobaltic oxide,
manganese dioxide and silver oxide in the proportion of 20:34:46 catalyzed
the reaction of carbon monoxide at room temperature. The studies were
extended and it was soon found that the best catalysts contained active
manganese dioxide as the chief constituent. This was prepared by the
reaction between potassium permanganate and anhydrous manganese
sulfate in the presence of fairly concentrated sulfuric acid. It also developed
that the minimum silver oxide content decreased progressively as the

number of components increased from 2 to 4. The standard catalyst
(Hopcalite) finally adopted for production consisted of 50 per cent
manganese dioxide, 30 per cent copper oxide, 15 per cent cobaltic oxide
and 5 per cent silver oxide. The mixture was prepared by precipitating and
washing the first three oxides separately, and then precipitating the silver
oxide in the mixed sludge. After washing, this sludge was run through a
filter press, kneaded in a machine, the cake dried and ground to size. While
it is not difficult to obtain a product which is catalytically active, it requires
a vigorous control of all the conditions and operations to assure a product at
once active, hard, dense and resistant as possible to the deleterious action of
water vapor.

Fig. 40.—Tanks and Press for Small Scale Manufacture
of Carbon Monoxide Absorbent.

Hopcalite acts catalytically and therefore only a layer sufficiently deep
to insure close contact of all the air with the catalyst is needed. One and a

half inches (310 gm.) were found ample for this purpose.
The normal activity of Hopcalite requires a dry gas mixture. This was
secured by placing a three-inch layer of dry granular calcium chloride at the
inlet side of the canister.
Because of the evolution of heat, a cooling arrangement was also used
in the Hopcalite canisters.
The life of this canister was the same irrespective of whether its use was
continuous or intermittent. The higher the temperature the longer the life
because Hopcalite is less sensitive to water vapors at higher temperatures.
Since, if the effluent air was sufficiently dried, the Hopcalite should
function indefinitely against any concentration of carbon monoxide, the life
of the canister is limited solely by the life of the drier. Therefore the net
gain in weight is a sure criterion of its condition. After many tests it was
determined that any canister which had gained more than 35 grams above
its original weight should be withdrawn. The canisters, at the time of
breakdown, showed a gain in weight varying between 42 and 71 grams,
with a average of 54 grams. It is really, therefore, the actual humidity of the
air in which the canister is used that determines its life.

Fig. 41.—Navy Head Mask and Canister.

CHAPTER XII
DEVELOPMENT OF THE GAS MASK
While in ordinary warfare the best defense against any implement of
war is a vigorous offense with the same weapon, Chemical Warfare presents
a new point of view. Here it is very important to make use of all defensive
measures against attack. Because of the nature of the materials used, it has
been found possible to furnish, not only general protection, but also
continuous protection during the time the gas is present.
The first consideration in the protection of troops against a gas attack is
the provision of an efficient individual protective appliance for each soldier.
The gas attack of April 22, 1915 found the Allies entirely unprepared and
unprotected against poisonous gas. While a few of the men had the presence
of mind to protect themselves by covering their faces with wet cloths, the
majority of them became casualties. Immediately steps were taken to
improvise protective devices among which were gags, made with rags
soaked in water or washing soda solution, handkerchiefs filled with moist
earth, etc. One suggestion was to use bottles with the bottom knocked off
and filled with moist earth. The breath was to be taken in through the bottle
and let out through the nose; but as bottles were scarce and few of them
survived the attempt to get the bottom broken off, the idea was of no value.
The first masks were made by the women of England in response to the
appeal by Lord Kitchener; they consisted of cotton wool wrapped in muslin
or veiling and were to be kept moist with water, soda solution or hypo.

English Masks

The Black Veiling Respirator. The first form of the English mask is
known as the Black Veiling respirator and consisted of cotton waste
enclosed in a length of black veiling. The waste was soaked in a solution of:
Sodium thiosulphate 10 lbs.
Washing soda 2.5 lbs.

Glycerine 2 lbs.
Water 2 gals.
The glycerine was put in to keep the respirator moist, thus obviating the
need for dipping before use.

Fig. 42.—Early Gas Protection.

The respirator was adjusted over the mouth and nose, the cotton waste
being molded to the shape of the face and the upper edge of the veiling
pulled up so as to protect the eyes. These respirators were used in the
attacks of May 10th and 12th, 1915 and were reasonably efficient against
the low concentration of chlorine then used; they were difficult to fit exactly
to the face, which resulted in leakage. The cotton waste often became
lumpy and had to be shredded out or discarded.
The Hypo Helmet. The next development of the British protection was
the so-called Hypo helmet. This is said to have resulted from the suggestion
of a Canadian sergeant that he had seen a German pulling a bag over his
head during a gas attack. It consisted of a flannel bag soaked in the same

solution as was used for the veiling respirator and was fitted with a pane of
mica as a window. The helmet was tucked down inside the jacket which
was then buttoned up tightly around the neck. As may be seen from Figure
43, this would not prove very satisfactory with the American type of
uniform.
This helmet had many advantages over the veiling respirator but the
window often became cracked or broken from the rough treatment in the
trenches. Later the mica was replaced by celluloid and still later by glass
eyepieces set in metal rings. These were very effective against chlorine in
the field.
The P and PH Helmets. During the summer of 1915 it became evident
that phosgene-chlorine mixtures would be used in gas attacks and it was
therefore necessary to provide protection against this. The hypo helmet,
which offered no protection against phosgene, was soaked in an alkaline
solution of sodium phenolate (carbolic acid) containing glycerine, and with
this new form of impregnation was called the P helmet. It protected against
300 parts of phosgene in a million of air. Since this solution attacks flannel,
two layers of flannelette were used. The helmet was further improved by
the addition of an expiratory valve, partly to prevent the man from
breathing any of his own breath over again and partly to prevent the
deterioration of the alkali of the mask by the carbon dioxide of the expired
air.
The protection was later further increased by the addition of
hexamethylenetetramine, and this mask is known as the PH helmet. This
increased the protection to 1,000 p.p.m.
The early types of helmet offered no protection against lachrymators.
For this purpose goggles were used, the later types of which had glass
eyepieces and were fitted around the eyes by means of rubber sponge.
While intended for use only after a lachrymatory bombardment, the troops
frequently used them during and after an ordinary gas attack when the mask
should have been worn. Consequently they were withdrawn.
The PH helmet was unsatisfactory because of the following reasons:

(1) It was warm and stuffy in summer;
(2) It deteriorated upon exposure to air;

(3) It was incapable of further development;
(4) It had a peculiar odor and, when wet, frequently
burned the foreheads of the men;
(5) It offered practically no protection against lachrymators.

Fig. 43.—Method of Wearing
the P. H. Helmet

Fig. 44.—Early Type of Standard
(British) Box Respirator (S. B. R.)

Box Respirator. The increasing concentration of gas from cylinder
attacks and the introduction of shell, with such gases as chloropicrin and
superpalite, led, early in 1916, to very definite and constructive efforts on
the part of the British to increase the protection offered by the mask. The
result was a “polyvalent” respirator of the canister type (the Standard Box
Respirator). This mask was probably the result of experience with oxygen
apparatus in mine rescue work. The lines on which this canister was
modeled involved the use of a canister filled with highly sensitive absorbent
charcoal mixed with or alternating in layers with oxidizing granules of
alkaline permanganate. It was the result of innumerable experiments, partly
conducted in France but mostly in England under the direction of the late
Lieut. Col. Harrison, who was almost entirely responsible for the wonderful
production of this respirator.

The respirator (Figure 44) consisted of the canister mentioned above,
which is attached by a flexible tube to a facepiece or mask. The facepiece is
made of rubberized fabric and fits the face so that there is little or no
leakage. This is secured by means of tape and elastic bands which fit over
the head. The nose is closed by means of clips, which are wire springs with
rubbered jaws covered with gauze (Fig. 45). Breathing is done through a
mouthpiece of rubber; the teeth close on the rubber tabs and the rubber
flange lies between the teeth and the lips. The expired air finds exit through
a rubber flutter valve in an angle tube just outside the mask. This
arrangement furnishes a double line of protection; if the face piece is
punctured or torn, gas-containing air cannot be breathed as long as the
noseclip and mouthpiece are in position.
The early English canister was packed with 675 cc. of 8-14 mesh war
gas mixture, 40 per cent of which was wood charcoal and 60 per cent
reddish brown soda-lime granules. The metal dome at the bottom of the can
was covered with a thin film of cotton. At two-thirds of the distance to the
top was placed a paper filter and a heavy wire screen which differs from our
heavy screen in that it is more loosely woven. The mixture was covered
with a cotton filter pad and a wire screen, over which was placed the wire
spring.
The use of this mask ensures that all the air breathed must enter the
lungs through the canister. This air passage is entirely independent of leaks
in the facepiece, due either to a poor fit about the face or to actual leakage
(from a cut or tear) of the fabric itself. The facepiece is readily cleared of
poison gases which may leak in. This is accomplished by taking a full
inspiration, releasing the noseclip, and exhaling through the nose, which
forces the air out around the edges of the facepiece.
On the other hand, this type of mask possesses a number of very
obvious disadvantages, particularly from a military point of view:
The extreme discomfort of the facepiece. This discomfort arises from a
number of causes certain of which are inherent in this type of mask, among
them being: (a) the noseclip, (b) the mouthpiece, and (c) the lack of
ventilation within the facepiece chamber.
Aside from the actual physical discomfort of the noseclip and
mouthpiece, which becomes intense after long periods of wearing, this

combination forces upon the wearer an unnatural method of respiration to
which it is not only difficult to become accustomed, but which also causes
extreme dryness of the throat. The mouthpiece greatly increases salivation
and as swallowing is rather more difficult with the nose closed, this adds
another extremely objectionable feature.

Fig. 45.—Interior of S. B. R., Showing
Cotton Wrapped Noseclips.

Fig. 46.—French M-2 Mask.

The lack of ventilation in the facepiece chamber entraps the heat
radiating from the face and retains the moisture which is constantly
evaporating from the skin. This moisture condenses on the eyepieces, and
even if cleared away by the use of a so-called anti-dimming paste, usually
makes vision nearly impossible.

French Masks

M-2 Mask. The early protection of the French Army was obtained from
a mask of the type M-2 (Fig. 46).
This mask consists of a number of layers of muslin impregnated with
various absorbent chemicals. A typical mask was made up of 20 layers of
cheesecloth impregnated with Greasene and 20 layers impregnated with
Complexene. These solutions were made up as follows:

Complexene: 39.0 lbs. Hexamethylenetetramine
37.5 lbs. Glycerine
27.5 lbs. Nickel sulfate (NiSO₄·7 H₂O)
11.8 lbs. Sodium carbonate (Na₂CO₃)
Water

Greasene: 107.0 lbs. Castor oil
81.0 lbs. Alcohol (95%)
10.7 lbs. Glycerine (90%)
3.1 lbs. Sodium hydroxide (NaOH)
This mask fits the face tightly and as a consequence the inhaled air can
be obtained only by drawing it through the pores of the impregnated fabric.
There is no outlet valve. The exhaled air makes its escape through the
fabric. The eyepieces are made of a special non-dimming celluloid. The
mask is protected from rain by a flap of weather proof fabric, which also
protects the absorbent chemicals from deterioration.
At the beginning of the war the United States experimented
considerably with the French mask. Several modifications of the
impregnating solutions were suggested, as well as methods of application.
One of these was to separate the components of the complexene solution
and impregnate two separate layers of cloth; this would make a three-layer
mask. In view of the phosgene which was in use at that time, the following
arrangement was suggested:

20 layers of hexamethylenetetramine,
10 layers of nickel sulfate-sodium carbonate,
10 layers of greasene.

This arrangement was more effective than the original French mask and
offered the following protection when tested against the following gases
(concentration 1 to 1,000, rate 30 liters per minute):
Phosgene 65 minutes
Hydrocyanic acid 60 minutes
Chlorine 60 minutes

Fig. 47.—Interior View
of M-2 Mask.

Fig. 48.—French Artillery Mask,
Tissot Type.

Tissot Mask. The French deserve great credit for their development of
the Tissot type mask. This was first issued to artillerymen, stretcher bearers,
and certain other special classes of soldiers to furnish them with protection
and yet enable them to work with greater efficiency because of the decrease
in resistance to breathing. The mask (Fig. 48) resembles the British box
respirator in that it consists of a canister and rubber facepiece, but differs in
that the mouthpiece and noseclip are lacking. The inhaled air enters the
mask from two tubes which open directly under the eyepieces and allow the
air to sweep across them. This removes, by evaporation, the condensed
moisture of the breath from the eyepieces, which otherwise would obstruct
the vision. The circulation of the fresh air in the mask also removes and
dilutes lachrymatory gases which may filter through the mask. The exhaled
air escapes through a simple outlet valve. This type of mask is
advantageous because:

(1) The facepiece is tight and comfortable.
(2) The eyepieces do not become dimmed.
(3) There is no difficulty in speaking.
(4) Salivation is eliminated because of the absence of the
mouthpiece.
(5) It is generally more comfortable than the box respirator.

This mask, however, was made of thin rubber of great flexibility which,
while affording a perfect fit, did not possess sufficient durability to
recommend it as the sole defense of the wearer.
The canister is markedly different from all other canisters described in
this chapter in that a highly hygroscopic chemical absorbent is used. An
approximate determination showed about 70 per cent sodium hydroxide.
The use of caustic soda in the canister is made possible by the intermixing
of steel wool with the granules of caustic. A layer of absorbent having the
appearance of vegetable charcoal is placed at the top of the canister.
The canister has the shape of a rectangular prism 8 × 6½ × 2½ inches;
and, owing to the use of steel wool, is large in proportion to the weight of
absorbent contained. Valves are supplied which prevent exhalation through
the canister. When not in use the opening in the bottom of the canister is
plugged with a rubber stopper to protect the absorbents from moisture. The
canister is carried against the body and is connected to the facepiece with a
flexible rubber-fabric tube.
A. R. S. Mask (Appareil Respiratoire Special). One of the latest types
of French mask is the so-called A. R. S. mask, which is based upon, or at
least resembles closely, the German mask. This is a frame mask made from
well rubberized balloon material, provided on the inside with a lining of
oiled or waxed linen and fitted with a drum which is screwed on. The mask
is provided with eyepieces of cellophane, fastened by metal rings into
rubber goggles, which are sewed in the mask. A metal mouth-ring is tied in
the mask with tape. This ring is placed somewhat higher than in the German
mask, in this way reducing the harmful space under the mask. An inlet and
outlet valve is placed in the mouth-ring; the first is of mica while the other,
which is in direct communication with the interior of the mask, is of rubber.
On the inside of the mask, in front of the valves, a baffle is sewed in,
whereby the inhaled air is forced to pass in front of the eyepieces to prevent

dimming and, at the same time, condensed vapor is prevented from entering
the valves.

Fig. 49.—French A. R. S. Mask.

The mask or head straps are arranged in the same way as on the latest
M-2 mask, i.e., one elastic band is placed across the top of the head and the
other across the back; the two are joined by an elastic. Below these two
straps is an adjustable elastic neck band. The drum is made of metal similar
in shape to the German drum and fits in the mouth-ring by means of a
thread. It is made tight by a rubber ring as in the German mask. The thread
differs from that on the German mask, making an interchange of canisters
impossible. The canister or drum includes a bottom screen, springs and wire
screens between the layers. It is closed by a perforated bottom. There are
three layers. On the top is a thin layer of absorbent cotton. Beneath this is a

central layer of charcoal, which is a little finer than the German charcoal.
The lower layer consists of soda-lime, mixed with charcoal and zinc oxide
and moistened with glycerine.

German Mask

The early type of German mask probably served as the model for the
French A. R. S. mask. The facepiece was made of rubber, which was later
replaced by leather because of the shortage of rubber. The following is a
good description of a typical German facepiece:
“The facepiece of the German mask was made of one piece of leather,
with seams at the chin and at the temples, giving it roughly the shape of the
face. The leather was treated with oil to make it soft and pliable, also to
render it impervious to gases. The dressed surface was toward the inside of
the mask. A circular steel plate, 3 inches in diameter, was set into the
facepiece just opposite the wearer’s nose and mouth, with a threaded socket
into which the drum containing the absorbents screwed. A rubber gasket
(synthetic?) held in place by a sort of pitch cement, secured a gas-tight joint
between the drum and the facepiece. There were no valves, both inhaled
and exhaled air passing through the canister. The eyepieces were inserted by
means of metal rims with leather washers, and were in two parts: (a) a
permanent exterior sheet of transparent material (‘cellon’) resembling
celluloid, and (b) an inner removable disc which functioned as an anti-
dimming device. This latter appeared to be of ‘cellon’ coated on the side
toward the eye with gelatin, and was held in position by a ‘wheel’ stamped
from thin sheet metal, which screwed into the metal rim of the eyepiece
from the inside. The gelatin prevented dimming by absorbing the moisture,
but wrinkled and blistered and became opaque after a few hours’ use, and
could not be changed without removing the mask. The edge of the facepiece
all around was provided with a bearing surface consisting of a welt of finely
woven cloth about one inch wide sewed to the leather. In some instances
this welt was of leather of an inferior grade. The edge of the facepiece was
smoothed over by a coat of flexible transparent gum, probably a synthetic
compound.”

Fig. 50.—German Respirator.

Fig. 51.—The German Respirator

1. Smoke Filter Extension.
2. Canister.
3. Ring for Protecting Eye Piece.
4. Anti-dimming Disc Envelope.
5. Carrying Case.
6. Cloth Wallet for Extra Canister (1918).
7. Can for Extra Canister (1916).
8. Assembled Respirator.
9. Face Piece.
10. Anti-dimming disc.

German Canister. The general appearance of the canister (Sept., 1916
Type) is that of a short thick cylinder slightly tapered and having at the
smaller end a threaded protrusion or neck by which it is screwed onto the
facepiece. The cylinder is about 10 cm. in diameter and about 5 cm. in

length. In the canister are three layers of absorbents of unequal thickness
separated by disks of fine mesh metal screen. The canister is shipped in a
light sheet iron can 10 cm. in diameter and 8 cm. high. The can is
shellacked and is lined with paper packing board. The container is made air-
tight by sealing with a strip of adhesive tape.

Fig. 52.—Cross Section of 1917 and 1918 German Canisters.

Absorbents.
Absorbent. Composition. Weight. Volume.
1917. No. 1. Chemical Absorbent. 66 gr. 105 cc.
No. 2. Impregnated Charcoal. 36 gr. 85 cc.
No. 3. Chemical Absorbent. 15 gr. 45 cc.
1918. No. 1. Impregnated Charcoal. 58 gr. 185 cc.
No. 2. Chemical Absorbent. 29 gr. 45 cc.

Total Volume of Absorbents, 1917, 235 cc. = 14.3 cu. in.
1918, 230 cc. = 14.0 cu. in.
Total Weight of Absorbents, 1917, 117 gr.
1918, 87 gr.
Volume of Air Space above Absorbents = 50 cc. = 3.1 cu. in.

Body. The body of the canister is made of sheet metal (probably iron),
which is protected on the outside with a coat of dark gray paint and on the
inside with a japan varnish. For ease in assembling the sides of the canister
have a gentle taper, and are formed so as to supply a seat for each of the
follower rings. The protrusion or neck has about six threads to the inch, the
pitch of the screw being 4 mm. The lower part of the body is rolled so as to
give a finished edge, and the upper part of the cylinder is grooved to receive
the top support.
The first screen is double, consisting of a coarse top screen five to six
mesh, per linear inch, and immediately below, a finer screen of 30-40 mesh,
per linear inch. The top support is a rigid ring of metal with two cross arms,
which give added, strength to the ring and support to the screens. It springs
into a groove at the top of the body and forms the support for the contents
of the canister. Both screens are made of iron wire and the top support is
made of iron (probably lightly tinned).
The second screen, which separates the second and third absorbents, is
double, consisting of two disks of 30-40 mesh iron screen. Both screens are
held in place by a follower ring.
The third screen is single, but otherwise it is exactly similar to the
second screen. It serves to keep separate the layers of absorbents No. 1 and
No. 2.
The fourth screen (30-40 mesh) is made of iron wire and is held to the
bottom support by six cleats which are punched from the body of the
support. The bottom support is simply a flanged iron cover for the bottom
of the canister. It is punched with 79 circular holes each 4 mm. in diameter
and is painted on the outside to match the body of the canister. The screen
and the inside of the bottom support or cover are coated with a red paint.

American Mask

At the entrance of the United States into the war, three types of masks
were available: the PH helmet, the British S. B. R. and the French M-2
masks. Experiments were made on all three of these types, and it was soon
found that the S. B. R. offered the greatest possibilities, both as regards
immediate protection and future development. During the eighteen months

which were devoted to improvement of the American mask, the facepiece
underwent a gradual evolution and the canister passed through types A to L,
with many special modifications for experimental purposes. The latest
development consisted in an adaptation of the fighting mask to industrial
purposes. For this reason a rather detailed description of the construction of
the facepiece and of the canister of the respirator in use at the close of the
war (R. F. K. type) may not be out of place. The mask now adopted as
standard for the U. S. Army and Navy is known as the Model 1919
American mask, with 1920 model carrier, and will be described on page
225.

Fig. 53.—Diagrammatic Sketch of
Box Respirator Type Mask.

Facepiece. The facepiece of the R. F. K. type Box Respirator is made
from a light weight cotton fabric coated with pure gum rubber, the finished

fabric having a total thickness of approximately ¹/₁₆ inch. The fit of the
facepiece is along two lines—first, across the forehead, approximately from
temple to temple; second, from the same temporal points down the sides of
the face just in front of the ears and under the chin as far back as does not
interfere with the Adam’s apple. In securing this fit, the piece of stock for
the facepiece is died out of the felt and pleated up around the edges to
conform to this line. After this pleating operation, the edges of the fabric are
stitched to a binding frame similar to a hat-band made up of felt or
velveteen covered with rubberized fabric. All the stitching and joints in the
facepiece are rendered gas-tight by cementing with rubber cement. This
facepiece is made in five sizes ranging from No. 1 to No. 5, with a large
majority of faces fitted by the three intermediate sizes, 2, 3, 4.
Harness. The function of the harness is to hold the mask on the face in
such a way as to insure a gas-tight fit at all points. Because of the great
variations in the conformation of different heads, this problem is not a
simple one. Probably, the simplest type of harness, as well as the one which
is theoretically correct, consists of a harness in which the line of fit across
the forehead is extended into an elastic band passing around the back of the
head, while the line of fit around the side of the face and chin is similarly
extended into another elastic tape passing over the top of the head; these
should be held in place by a third tape, preferably non-elastic, attached to
the mask at the middle of the forehead and to the middle points of the other
tapes at a suitable distance to hold them in their proper positions.
The discomfort of the earlier types of harness has been remedied, in a
large measure, by the development of a specially woven elastic web which,
for a given change in tension, allowed more than double the stretch of the
commercial weaves. There is still much room for valuable work in
developing a harness which will combine greater comfort and safety. The
following points should always be observed in harness design:
(1) The straps should pull in such a direction that as large a component
as possible of the tension of the strap should be available in actually holding
the mask against the face.
(2) The number of straps should be kept to a minimum in order to avoid
tangling and improper positioning when put on in a hurry by an
inexperienced wearer.

Eyepieces. One of the most important parts of the gas mask, from the
military point of view, is the eyepiece. The primary requirement of a good
eyepiece is that it shall provide a minimum reduction in clarity of vision
with a maximum degree of safety to the wearer. The clarity of vision may
be affected in one of several ways: (1) by abrasion of the eyepieces under
service conditions; (2) irregularities in the surface and thickness of the
eyepiece, causing optical dispersion; (3) absorption of light by the eyepiece
itself; (4) dimming of the eyepieces due to condensation of moisture
radiating from the face or in the exhaled air.
Three types of eyepieces were used but by the end of the war the first
two types had been abandoned.
(1) Ordinary celluloid.
(2) Various hygroscopic forms of celluloid, known as non-dimming
eyepieces.
(3) Various combinations of glass and celluloid, known as non-
breakable eyepieces.
Celluloid was used first, due to its freedom from breakage. It is not
satisfactory because it is rapidly abraded in use, turns yellow, thus
increasing its light absorption, has relatively uneven optical surfaces and
becomes brittle after service.
The various forms of non-dimming lenses function by absorbing the
water which condenses on their surfaces, either by combining individual
drops into a film which does not seriously impair vision, by transmitting it
through the surface and giving it off on the exterior or by a combination of
these mechanisms. With the exception that they are non-dimming, they are
open to all the objections of the celluloid eyepiece and, as a matter of fact,
were never tried out in the field.
The so-called non-breakable eyepieces are formed by cementing
together a layer of celluloid between two layers of glass.[25] This results in
an almost perfect eyepiece. Any ordinary blow falling upon such an
eyepiece does no more than crack the glass, which remains attached to the
celluloid coating. Except in extreme cases, the celluloid remains unbroken
and there is relatively slight danger of a cracked eyepiece of this sort
leaking gas.

In the matter of flying fragments, the type of eyepiece consisting of a
single layer of celluloid and glass with the celluloid placed next to the eye,
has probably a slight advantage over the type in which there is glass on both
sides. However, the superior optical surface of the latter type, coupled with
its greater freedom from abrasion of the surface led to the adoption of this
type known as “triplexin” in the mask produced in the later part of the
American manufacturing program. It should be pointed out in connection
with this type of eyepiece that it is possible to make it as perfect optically as
desired by using the better grades of glass. While the optical properties of
these eyepieces undoubtedly suffer somewhat with age, due to the
discoloration of the celluloid, it can be safely said that this material, located
as it is between the layers of glass and relatively little exposed to
atmospheric conditions, will probably be far less affected in this way than is
the ordinary celluloid eyepiece.

Fig. 54.—American Box Respirator,
Showing Improved Rubber Noseclip.

The position of the eyepiece is very important; the total and the
binocular fields of vision should be kept at a maximum.
Nose clip. The noseclip is probably the most uncomfortable feature of
the types of mask used during the War. While a really comfortable nose pad
is probably impossible, the comfort of the clip was greatly improved by
using pads of soft rubber and springs giving the minimum tension necessary
to close the nostrils.
Mouthpiece. The design of the mouthpiece should consider the size and
shape of the flange which goes between the lips and teeth; this should be
such as to prevent leakage of gas into the mouth and should reduce to a
minimum any chafing of the gums. The opening through the mouthpiece is
held distended at its inner end by a metallic bushing to prevent its collapse,
if, under stress of excitement, the jaws are forced over the flange and
closed. Rubber has proved a very satisfactory material for this part of the
facepiece.
Flexible Hose. The flexible hose leads from the angle tube to the
canister. This should combine flexibility, freedom from collapse, and
extreme physical ruggedness. These specifications are met successfully by
the stockinette-covered corrugated rubber hose. The angular corrugations
not only give a high degree of flexibility but are extremely effective in
preventing collapse. The flexibility gained by this construction is not only
lateral but also longitudinal; a hose having a nominal length of 10 inches
functions successfully between lengths of 8 and 12 inches. The covering of
stockinette, which is vulcanized to the rubber in the manufacturing process,
adds materially to the mechanical strength by preventing incipient tears and
breaks.
Exhalation Valve. The exhalation valve allows the exhaled air to pass
directly to the outside atmosphere. (This valve is not found on the German
mask.) This valve has the following advantages:
(1) It tends to reduce very materially the dead air space in the mask.
(2) It prevents deterioration of the absorbent on account of moisture and
carbon dioxide of the expired air.
(3) It reduces the back pressure against expiration, since it is
unnecessary to breathe out against the resistance of the canister.

The disadvantage, which may under certain conditions be very serious,
is that, if for any reason the valve fails to function properly, inspiration will
take place through the valve. It can be readily seen that any failure of this
nature will allow the poisonous atmosphere to be drawn directly into the
lungs of the wearer.
The type of valve generally used is shown in Fig. 55, which shows one
of these valves mounted and unmounted. While it is rather difficult to give a
clear description of its construction, the valve may be considered as a
flattened triangular sack of rubber, whose altitude is two or three times the
base and from which all three corners have been clipped, each giving
openings into the interior of the sack. The opening at the top is slipped over
the exhalation passage of the angle tube, and the air passes out through the
other two corners. Closure is obtained by the combination of two factors,—
first, the difference in atmospheric pressure, and second, the tension due to
mounting a section which has been cured in the flat over an elliptical
opening.

Fig. 55.—American Type Exhale Valve,
Mounted and Unmounted.

In order to protect the flutter valve from injury and from contact with
objects which might interfere with its proper functioning, the later types of
valve were provided with a guard of stamped sheet metal.

Canisters

During the development of the facepiece, as discussed above, the
American canister underwent changes in design which have been
designated as A to L. These changes were noted by the different colored
paints applied to the exterior of the canister.
Type A canister was exactly like the British model then in use, except
that it was made one inch longer because it was realized that the early
absorbents were of poor quality. The canister was made of beaded tin plate
and was 18 cm. high. The area of the flattened oval section was 65 sq. cm.
In the bottom was a fine wire dome 3.4 cm. high. The valve in the bottom
was integral with the bottom of the container, there being no removable
plug for the insertion of the check valve. The absorbents were held in place
by a heavy wire screen on top and by two rectangular springs.

Fig. 56.—American Canister, Type A.

Inhaled air entered through the circular valve at the bottom of the
canister, passed through the absorbents and through a small nipple at the
top.
The filling consisted of 60 per cent by volume of wood charcoal,
developed by the National Carbon Co., and 40 per cent of green soda lime,
developed and manufactured by the General Chemical Company, Easton,
Pa. The entire volume amounted to 660 cc. The early experiments with this
volume of absorbent showed that ⅖ soda-lime was the minimum amount
that could be used and still furnish adequate protection against the then
known war gases. It was, therefore, decided to use ⅖ soda-lime and ⅗
charcoal by volume and this proportion has been adhered to in all of the
later types of canisters. It is interesting to note that these figures have been
fully substantiated by the later experimental work on canister filling.

The charcoal and soda-lime were not mixed but arranged in five layers
of equal volume, each layer, therefore, containing 20 per cent of the total
volume. The layers were separated by screens of crinoline. At the top was
inserted a layer of terry cloth, a layer of gray flannel, and two steel wire
screens. The cloth kept the fine particles of chemicals from being drawn
into the throat of the person wearing the mask.
This canister furnished very good protection against chlorine and
hydrocyanic acid and was fairly efficient against phosgene, but it was
useless against chloropicrin. These canisters were never used at the front,
but served a very useful purpose as experimental canisters and in training
troops.
It was soon found that better protection was obtained if the absorbents
were mixed before packing in the canister. This procedure also simplified
the method of packing and was used in canister B and following types.
Among other changes introduced in later types were: The integral valve was
replaced by a removable check valve plug which enabled the men in the
field to adjust the valve in case it did not function properly. The mixture of
charcoal and soda-lime was divided into three separate layers and these
separated by cotton pads. The pads offered protection against stannic
chloride smokes but not against smokes of the type of sneezing gas. The
green soda-lime was replaced by the pink granules. In April, 1918, the mesh
of the absorbent was changed to 8 to 14 in place of 6 to 14.
About July 1, 1918, the authorities were convinced by the field forces of
the Chemical Warfare Service that the length of life of the chemical
protection of the standard H canister (the type then in use) was excessive
and that the resistance was much too high. Type J was therefore adopted,
July 27, 1918. In this the volume of the absorbent was reduced from 450 cc.
to 300 cc. It was packed in two layers, ⅔ in the bottom and ⅓ in the top.
One pad was placed between the layers and one on top. This change gave a
lowering of the resistance of 27 per cent (to 2.5 inches) at a sacrifice of 50
per cent of the length of life of the canister, but not of protection during the
shortened life. Type L differed from this only in having 325 cc. of
absorbent, a change made to decrease leakage about the top cotton pad.

Fig. 57.—U. S. Army Canister, Type J.

The following table shows the relative efficiency of various canisters:
U. S., British, French,
p. p. m. German
Type H S. B. R. A. R. S.
Chloropicrin 1000 770 17 2 43
Phosgene 2500 85 54 5 16
Hydrocyanic acid 500 70 90 — 10
Mustard gas 100 1800 — 35 195
The figures represent time in minutes till the first traces of gas begin to
come through.

Fig. 58.—Type J Canister and Contents.

Manufacture

The following description of the manufacture of the gas mask at the
Long Island plant is taken from an article by Col. Bradley Dewey[26]:
“Incoming Inspection—A thorough 100 per cent inspection was made of
each part before sending it to the Assembly Department. The inspectors
were carefully chosen and were sent to a school for training before they
were assigned to this important work. Every feature found to be essential to
the manufacture of a perfect gas mask was carefully checked.
“The incoming inspection of the flexible rubber hose leading from the
canister to the facepiece can be taken as an illustration. Each piece of hose
was given a visual inspection for buckles or blisters in the ends or in the
corrugations; for cuts, air pockets, or other defects on the interior; for loose
seams where fabric covering was cemented to the rubber tube; for weaving
defects in the fabric itself; and for careless application of the cement.

Special tests were conducted for flexibility, as a stiff hose would produce a
strain on the soldier’s mouth; for permanent set to insure that the hose was
properly cured; for the adhesion of the fabric covering to the hose; and for
kinking when the hose was doubled on the fingers. Finally each piece was
subjected to a test for leaks under water with a pressure of 5 lbs. per sq in.
“Each eyepiece and the three-way metal connection to the facepiece
were subjected to a vacuum test for leakage. The delicate exhalation valve
was carefully examined for defects which would be liable to cause leakage.
Fabric for the facepiece was given a high-tension electrical test on a special
machine developed at the plant to overcome the difficulty met in the
inspection of this most important material. It was of course necessary that
the facepiece fabric be free from defects but just what constituted a defect
was the source of much discussion. The electrical test eliminated all
personal views and gave an impartial test of the fabric. The machine
consisted of two steel rolls between which a potential difference of 4,000
volts was maintained; the fabric was led through the rolls and wherever
there was a pinhole or flaw the current arced through and burned a clearly
visible hole.
“Preliminary Facepiece Operations—Blanks were died out from the
facepiece fabric in hydraulic presses. Each face blank was swabbed to
remove bloom and the eye washers were cemented about the eyeholes. The
pockets for holding the noseclips were also cemented to the blanks. The
bands which formed a gas-tight seal of the mask about the face were died
out from rubberized fabric to which a felt backing was attached. The
harness consisting of elastic and cotton tapes was also sewed together at
this point.
“Facepiece Operations—The sewing machine operations were next
performed. First the died out blanks were pleated to form the facepiece. The
operator had to register the various notches in the blank to an accuracy of ¹/
₃₂ in. and to locate the stitches in some cases as closely as ¹/₆₄ in. The band
was next sewed to the periphery of the facepiece after which the harness
was attached. The stitches on the outside of the facepiece were covered with
liquid dope, which filled the needle holes and made the seams gas-tight.
“In addition to the inspection of each operation, the completed facepiece
was submitted to a control inspection to discover any defects that might

escape the attention of the inspectors on the various operations.
“Assembly Operations—The facepieces were now ready for assembly
and were sent for insertion of the eyepieces, which was done in specially
designed automatic presses. The eyepieces had to be carefully inserted so
that the facepiece fabric extended evenly around the entire circumference.
“Before manufacture began on a large scale, the most satisfactory
method of conducting each assembly operation was worked out and the
details standardized, so that operators could be quickly and efficiently
trained. No detail was considered too small if it improved the quality of the
mask. The assembly operations proceeded as follows:
“The exhalation valve was first joined to the three-way metal tube
which formed the connection between the facepiece, flexible hose, and
mouthpiece. Each valve was then tested for leakage under a pressure
difference of a one inch head of water. No valve was accepted which
showed leakage in excess of 10 cc. per min. under these conditions.
“The metal guard to protect the exhalation valve was next assembled,
followed by the flexible hose. The three-way tube was then assembled to
the facepiece by means of a threaded connection and the rubber mouthpiece
attached. To illustrate the attention to details the following operation may be
cited:
“The contact surfaces between each rubber and metal part were coated
with rubber cement before the parts were assembled. The connection was
then tightly wired, care being taken that none of the turns of wire should
cross and finally the wire was covered with adhesive tape so that no sharp
edges would be exposed.
“The masks, completely assembled except for the canisters, were
inspected and hung on racks on specially designed trucks which prevented
injury in transit, and were delivered to the Finishing Department.
“Canister Filling—Meanwhile the canisters were being filled, in
another building.
“The chemicals were first screened in such a way that the fine and
coarse materials were separated from the correctly sized materials. They
were then carried on a belt conveyor to the storage bins, whence they were
fed by gravity through pipes to various mixing machines. A special mixing

machine was developed to mix the carbon and granules in the proper
proportions for use in the canister. The mixed chemicals were then led to
the canister-filling machines. There was a separate mixing machine for each
filling machine, of which there were eighteen in all.
“The can-filling department was laid out in six units. Each unit had a
capacity of 20,000 cans per day. A system of double belt conveyors was
installed to conduct empty canisters to the machines and carry away the
filled ones.
“Each filling operation was carefully inspected and special stops were
placed on the belt conveyors so that a canister could not go to the next
operation without having been inspected. Operators and inspectors were
stationed on opposite sides of the belt. The chemicals were placed in the
canister in three equal layers which were separated by pads of cotton
wadding. The first layer was introduced from the filling machine (which
delivered automatically the proper volume of chemicals), the canister was
shaken to pack the chemicals tightly, the cotton baffle inserted, the second
layer of chemicals introduced and so forth. On top of the top layer of
chemicals were placed a wire screen and a specially designed spring which
held the contents of the canister securely in place. The metal top was then
fitted and securely soldered.
“Each canister was tested under water for possible leaks in joints or
soldering, with an air pressure of 5 lbs. per sq. in. A test was also made for
the resistance which it offered to breathing, a rate of flow of air through the
canister of 85 liters per min. being maintained and the resistance being
measured in inches of water.
“The filled canisters were then painted a distinctive color to indicate the
type of filling.
“Finishing Department—In the finishing department, the filled
canisters, were conducted down the middle of the finishing tables and
assembled to masks.

Fig. 59.

“The finished masks were then inspected, placed in unit boxes, ten to a
box, and returned for the final inspection.
“Final Inspection—Final inspection of the completely assembled masks
was as rigid as could be devised, and was closely supervised by army
representatives. Only the most painstaking, and careful women were
selected for this work and the masks were examined in every detail to
discover any defect that might have escaped previous inspection. Finally,
each mask was inspected over a bright light in a dark booth for small
pinholes which the ordinary visual inspection might not have detected.
“As a check on the quality on the final inspectors’ work a reinspection
of 5 per cent of the passed masks was conducted. Where it was found that a

particular inspector was making numerous mistakes, her eyes were
examined to see whether it was due to faulty eyesight or careless work.
Masks containing known defects were purposely sent to these inspectors to
determine whether they were capable of continuing the inspection work. In
this way the desired standard was maintained.
“A daily report of the final inspection was sent back to each of the
assembly departments involved so that defects might be eliminated
immediately and the percentage of rejects kept as low as possible.
“After the final inspection the masks were numbered, packed in
knapsacks, and the filled knapsacks placed in packing cases, twenty-four to
a case.”

Tissot Mask

The French, as has already been pointed out, early recognized that
certain classes of fighting men, as the artillerymen, needed the maximum of
protection with the minimum decrease in efficiency. The result of this was
the Tissot Mask. Before the United States entered the war, the British
standard box respirator had reached a greater degree of perfection, with far
greater ruggedness and portability. It was therefore adopted as the American
standard. At the time of the invention of the British box respirator and
practically up to the time the United States entered the war, masks were
worn only during the sporadic gas attacks then occurring and only for a
brief period at a time. As the war progressed, the men were compelled to
wear their masks for much longer periods (eight hours was not uncommon).
It was then seen that more comfort was needed, even at the expense of a
little safety.
The principle of the Tissot mask was correct so far as comfort was
concerned, since it did away with the irritating mouthpiece and noseclip,
but the chief danger in the French mask arose from the fact that the
facepiece was made of thin, pure gum rubber. The Research Division,
together with the Gas Defense Division, developed two distinct types of
Tissot masks. The first of these was the Akron Tissot, the second the Kops
Tissot. The best features of these have been combined in the 1919 Model.

Fig. 60.—American Tissot Mask,
Early Type.

Fig. 61.—American Tissot Mask,
Interior View.

1919 Model American Mask

Facepiece. This facepiece is made of rubberized stockinet about one-
tenth inch in thickness. The stockinet is on the outside only and is for the
purpose of strengthening and protecting the rubber which is of very high
grade. The facepiece is died out as a single flat piece from the stockinet
which is furnished in long rolls. The die is of such shape that when the
facepiece is sewed there is but one seam, and that between the angle tube
opening and the edge under the chin. This seam is sewed with a zigzag
stitch with the stockinet sides flat together. The seam is then stretched over
a jig, so as to form a flat butt joint. This seam is then cemented with rubber
cement and taped, inside and out, to make it thoroughly gas-proof.

The eyepiece openings are of oval shape with the longer axes horizontal
and considerably smaller than the finished eyepieces. The eyepieces being
circular, the cloth is stretched to accommodate them, giving the necessary
bulge to keep the cloth and metal of the eyepieces away from the face. The
harness has three straps on each side. Instead of the single strap over the top
of the head, two straps lead from directly over the eyes, both being made of
elastic the same as the other straps. All six straps are brought together
around a pad of felt and cloth about 2½ × 3½ inches at the back of the head.
This pad makes the harness much more comfortable.
The rubberized stockinet is reinforced on the inner or rubber side with
thin bits of cloth at all points where the straps are sewed on. The strap
across the temples just above the ears is sewed at two points, one about one-
half inch from the edge and the other about two inches from the edge. This
is for the purpose of helping press the cloth against the temples, thereby
adding to the gas-tightness for those heads that have a tendency to be
hollow at the temples. The lower strap is just above the chin and is for the
purpose of giving gas-tightness in that vicinity. All of the straps except the
two over the top of the head are attached to the pad with buckles, and are
thus capable of exact adjustment.
The eyepieces are of triplex glass in metal rings with rubber gaskets. In
pressing the rings home, the rubberized stockinet is turned and held
securely so that there is no possibility of pulling them out. The angle tube
containing the outlet valve and the connection to the corrugated tube
connecting with the canister is the same as with the latest model R. F. K.
mask. The only difference as regards the corrugated tube is that a greater
length is needed with the new carrier under the left shoulder. The total
length of the tube for this model is about 24 inches. On the inside of the
facepiece and connected to the angle tube inlet is a butterfly baffle of
rubber, so arranged that the incoming air is thrown upward and over the
eyepieces, thus keeping them clear no matter how much the exertion or
what the temperature, except in certain rare cases when the temperature is
down at zero F. or below.

Fig. 62.—1919 Model American Mask.

Canister

The canister is radically different from the canisters used in the R. F. K.
and earlier types. In the first place, it is longer, the total length finished
being 8 inches. It has two inlet valves at the top end protected by a tin cover
instead of the single inlet valve at the bottom of the earlier types. The two
inlet valves are each ⅝ inch in diameter and are made up of square flat
valves on the end of a short rubber tube. The rubber tube is fitted over a
short metal tube. Gas-tightness is obtained both by the pressing of the valve
against the round edge of the metal tube and by the pressure of the edges

against each other. These valves, while delicate, are proving very
satisfactory, and being simply check valves to prevent the air going back
through the canister, they are not vital. In case of failure, the eyepieces
would fog somewhat and the dead air space be increased by that held in the
inlet tube.
The canister consists really of two parts—an outer casing that is solid
and an inner perforated tin casing. Around the perforated tin is fitted a filter
of wool felt ³/₁₆ of an inch in thickness. This wool felt is very securely
fastened by turning operations to solid pieces of tin, top and bottom, so that
no air can get into the chemicals without passing through the filter. Thus the
air coming through the inlet valves at the top circulates around the loosely
fitting outside corrugated case to all parts of the filter and after passing
through the filter continues through the perforations of the tin into the
charcoal and soda-lime granules.
The chemicals are packed around a central wedge-shaped tube
extending about two-thirds the length of the can. The wedge is enlarged at
the top and made circular where it passes through the top of the can to
connect with the corrugated tube. The wedge-shaped inner piece is made of
perforated tin and is covered with thin cloth to prevent dust from the
chemicals passing into the tube and thus into the lungs. The cans are filled
from the bottom and are subjected to two mechanical jarring operations in
order to settle the chemicals thoroughly before the spring which holds them
in place is added. The outer tin cap protecting the inlet valves has two
openings on each side but none at the ends of the canister.

Fig. 63.—1919 Model American Mask
after Adjustment.

The carrier is a simple canvas case nearly rectangular, about one foot
wide and 15 inches in length. The width is just sufficient at the back to hold
the canister and the front part to hold the extra length of corrugated tube
and the facepiece. There are two straps, one passing over the right shoulder
and the other around the body. The one passing over the right shoulder has
two “V” shaped seams at the top so as to change the direction of the strap
over the shoulder in order that it will pull directly downward instead of
against the neck. The flap closing the case opens outward.

It has the usual automobile curtain fasteners. A secondary fastener at the
top of the opening is arranged so that when the tube is adjusted to the
proper length and the mask is adjusted to the face of the wearer, the flap can
be buttoned tightly over the corrugated tube and held tightly. This prevents
water from entering the case.
Figures 62 and 63 show the position of the carrier both with the
facepiece in the carrier and after adjustment. It will be noted that the carrier
does not interfere with the pack nor with anything on the front of the body.
The left arm hangs almost entirely natural over the case. It has been
thoroughly tried out by the Infantry, Cavalry, Artillery and Special Gas
Troops and adopted as eminently satisfactory.

Special Canisters

Navy. The early Navy canister is a drum much like the German canister.
The container is a slightly tapered metal cylinder, 9 cm. in diameter at the
bottom. The most satisfactory filling for this drum consists of two layers, 98
cc. in each, of a standard mixture of charcoal and soda-lime, separated by
cotton wadding pad. The filling is 6-20 mesh, instead of 8-14 mesh. A later
type is shown in Figure 41.
Carbon Monoxide. This canister is discussed in Chapter XI.
Ammonia. Ammonia respirators were needed by the Navy and also by
the workmen in refrigeration plants. Early protection was obtained by the
use of pumice stone impregnated with sulfuric acid. This had many
disadvantages, such as the amount of heat evolved, the caustic fumes
produced, high resistance and corrosion of the canister. To overcome these,
the “Kupramite” canister was developed. The filling consists of pumice
stone impregnated with copper sulfate. Pumice stone, 8 to 14 mesh, and
technical copper sulfate are placed in an evaporating pan in the ratio of one
part by weight CuSO₄·5H₂O to 1.5 parts pumice, and the whole is covered
with sufficient water to dissolve the salt at boiling temperature. The mixture
is then boiled down with constant stirring until crystallization takes place on
the pumice and the crystals are nearly dry. The pumice thus treated is then
removed from the dish, spread out and allowed to dry in the air. The fines
are then screened out on a 14-mesh sieve. Care must be taken in the

evaporating process that the absorbent is still slightly moist when taken
from the pan.

Fig. 64.—Early Type Navy Mask.
Contains noseclip and mouthpiece.

In packing the standard Army canister with kupramite a layer of
toweling is placed on top of the absorbent to filter out any fine particles
which might be drawn up from the absorbent, and the whole is held in place
by the usual heavy wire screen and spring. This method of packing is to be
used with the present mouthpiece type of army mask. If the new Tissot type
mask is used, a modification of the packing is desirable in order to
eliminate the trouble due to moisture given off by the absorbent during

service condensing on the eyepieces of the mask and thus impairing the
vision of the wearer. To remedy this defect a 1-in. layer of kupramite at the
top of the canister is replaced by activated charcoal or silica gel, preferably
silica gel. This decreases the humidity of the effluent air sufficiently to
prevent dimming of the eyepieces. If charcoal is used, a 2-8 cotton pad
(Eastern Star Furrier Co., Pawtucket, R. I.) is substituted for the toweling in
order to remove charcoal dust. The canister complete weighs about 1.7 lbs.

Fig. 65.—Ammonia Canister—“Kupramite.”

A canister containing 45 cu. in. of this material will protect a man
breathing at rest for at least 5 hours against 2 per cent ammonia and for 2½
hours against 5 per cent ammonia. Its advantages are large capacity and
activity, negligible heat of absorption, and cheapness.

Physiological Features of the Mask

For some time after the introduction of gas warfare, the gases used were
of the so-called non-persistent type. Under these conditions it was necessary

to wear the mask for only relatively short periods, after which the cloud
dissipated. With the increasing use of gas and the introduction of the more
persistent gases, particularly mustard gas, it not only became necessary to
wear the mask for long periods of time but also to do relatively heavy
physical work, such as serving artillery, when wearing the mask.

Fig. 66.—Ammonia Mask,
Showing Relative Size of Canister.

Under these conditions, it became evident that the wearing of the mask
caused a very great reduction in the military efficiency of the soldier. The
reasons for this reduction in efficiency have been made the subject of
extensive research by a group of the foremost physiologists and
psychologists of the country. As a result of their work, the causes
contributing to this reduction in efficiency may be grouped about the
following main factors:
(1) The physical discomfort of the mask arising from causes such as
pressure on the head and face, due to improperly fitting facepieces and
harness, the noseclip, and the mouthpiece.
(2) Abnormal conditions of vision, due to poor optical qualities in eye
pieces and restrictions of vision, both as to total field and binocular field.
(3) Abnormal conditions of respiration, among them being (a) the
unnatural channels of respiration caused by wearing the box respirator, (b)
increase in dead air space in respiratory circuit, and (c) the increase in
resistance to both inhalation and exhalation, the last two mentioned being
present to a greater or less degree in all types of mask.
Of these general subdivisions the various phases of the first two are so
evident that no further discussion will be given. The effects of the changed
conditions of respiration are, however, less obvious, and it may be of
interest to present in a general way the results of the research along this
line, particularly as regards the harmful effects of increasing the resistance
and dead air space in the respiratory tract above the normal.
The function of respiration is to supply oxygen to and remove carbon
dioxide from the blood as it passes through the lungs. This interchange of
gases takes place in the alveoli, a myriad of thin-walled air sacs at the end
of the respiratory tract where the air is separated by a very thin membrane
through which the gases readily pass. The volume and rate, or in other
words, the minute-volume, of respiration is automatically controlled by the
nerve centers in such a way that a sufficient amount of air is supplied to the
lungs to maintain by means of this interchange a uniform percentage of its
various constituents as it leaves the lungs. It will be readily seen therefore,
that anything which causes a change in the composition of the air presented
to the blood in the alveoli will bring about abnormal conditions of
respiration.

Inasmuch as the gaseous interchange between the lungs and the blood
takes place only in the terminal air sacs it follows that, at the end of each
respiration, the rest of the respiratory tract is filled with air low in oxygen
and high in carbon dioxide, which on inspiration is drawn back into the
lungs, diluting the fresh air. The volume of these passages holding air which
must be re-breathed is known as the anatomical dead air space.
Similarly, when a mask is worn the facepiece chamber and any other
parts of the air passage common to inspiration and expiration become
additional dead air space contributing a further dilution of oxygen content
and contamination by carbon dioxide of the inspired air in addition to that
occasioned by the anatomical dead space, which of course, is always
present and is taken care of by the functions normally controlling
respiration.
Major R. G. Pearce who directed a large amount of the research along
this line, sums up the harmful effects of thus increasing the dead air space
as follows:
1. Interpretation from the physiological standpoint:
(a) A larger minute-volume of air is required when breathing through
dead air space. This, interpreted on physiological grounds, means that the
carbon dioxide content of the arterial blood is higher than normal. The level
to which the content of carbon dioxide in the arterial blood may rise is
limited. Anything which wastefully increases the carbon dioxide level of the
blood decreases the reserve so necessary to a soldier when he is asked to
respond to the demand for exercise which is a part of his daily life.
(b) A larger minute-volume of air must be pulled through the canister,
which offers resistance proportional to the volume of air passing through it.
If resistance is a factor of harm, dead air space increases that harm, since
dead air space increases the volume of air passing through the canister.
(c) As will be noted below, the effect of resistance is a tendency to
decrease the minute-volume of air breathed. Dead air space increases the
minute-volume. Accordingly, if breathing is accomplished against
resistance and through a large volume of dead air space, the volume of air
breathed is reduced more in proportion to the actual needs of the body than
when breathing against resistance without the additional factor of dead

space; this, again, causes the level of carbon dioxide in the blood and
tissues to be raised to a higher level than normal, and thus again there is
some reserve power wasted.
2. Interpretation from the standpoint of the canister.
The life of the canister depends on the volume of the gas-laden air
passed through it. The dead space increases the minute-volume of air passed
through the canister and, therefore, shortens its life.
Physiologically, the reason for the harmful effects of breathing
resistance is more involved:
“The importance of resistance to breathing lies in: (1)
the effect on the circulation of the blood, and (2) the
changes in the lung tissue, which seriously interfere with
the gas exchange between the outside air and the blood.
Data have been presented to draw attention to the
seriousness of resistance to inspiration. In these reports, it
was suggested that the deleterious effects on the body
consist in changes in the blood pressure, increased work
of the right side of the heart, and an increase in the blood
and lymph content of the lungs. Resistance also decreases
the minute-volume of air breathed and thereby increases
the percentage of carbon dioxide in the expired air. The
foregoing changes are all deleterious.
“Although the chief problem of resistance in gas
mask design concerns inspiration, nevertheless resistance
to expiration is an important factor. The expired air of the
lungs contains carbon dioxide for which means of escape
must be provided. The expiratory act is more passive than
the inspiratory act, and resistance to expiration is,
therefore, more keenly felt than resistance to inspiration.
It is then imperative that the exhale valve be so arranged
as to allow for the escape of the entire amount of air
during the time of expiration with the least possible
resistance. The data of the laboratory indicate that
seldom, if ever, do expiratory rates rise above a velocity
of 150 to 175 per minute. The effect of resistance to

exhalation upon the vital organs of the body is not
dissimilar to that of inspiration.”

CHAPTER XIII
ABSORBENTS[27]
The absorbents used in both the British and American gas mask canister,
which afforded a degree of protection far superior to that of any other allied
or enemy nation except Germany, consisted of a mixture of charcoal and
soda-lime, as described in the preceding chapter. In general, a gas mask
absorbent must have certain requirements. These are: absorptive activity,
absorptive capacity, versatility, mechanical strength, chemical stability, low
breathing resistance, ease of manufacture and availability of raw materials.
Absorptive activity, or a very high rate of absorption, is one of the more
important properties of a satisfactory absorbent. A normal man when
exercising violently breathes about 60 liters of air per minute, and since
inhalation occupies but slightly more than half of the breathing cycle, the
actual rate at which gas passes through the canister during inhalation is
about 100 liters per minute. Calculated on the basis of the regular army
canister, this corresponds to an average linear air velocity of about 80 cm.
per second. On the average, therefore, a given small portion of the air
remains in contact with the gas absorbent for only about 0.1 second.
Besides this, the removal of the toxic material must be surprisingly
complete. Though the concentration entering the canister may occasionally
be as high as one half per cent, even the momentary leakage of 0.001 per
cent (ten parts per million) would cause serious discomfort and the
prolonged leakage of smaller amounts would have serious results in the
case of some gases. The activity of the present gas mask charcoal is shown
by the fact that it will reduce a concentration of 7000 parts per million of
chloropicrin to less than 0.5 part per million in less than 0.03 second.
Of equal importance is the absorptive capacity. That is, the absorbent
must be able to absorb and hold large amounts of gas per unit weight of
absorbent. Its life must be measured in days against ordinary concentrations
of gas. It is further necessary that the gas be held firmly and not in any
loose combination which might give up minute traces of gas when air is, for

long periods of time, breathed in through a canister which has previously
been exposed to gas.
The absorbents used must be of a type which can be relied upon to give
adequate protection against practically any kind of toxic gas (versatility).
The need of this is apparent when the difficulty of having separate canisters
for various gases is considered, as well as the difficulty in rapidly and
accurately identifying the gases and the possible introduction of new and
unknown gases. Fortunately, practically all of the toxic gases are very
reactive chemically or have relatively high boiling points and can therefore
be absorbed in large amounts by charcoal.
Absorbents must be mechanically strong in order to retain their
structure and porosity under conditions of transport and field use. Further,
they must not be subject to abrasion for the production of a relatively small
amount of fines would tend to plug the canister or to cause channels
through which the gas would pass without being absorbed.
Since the canister is filled several months before it is first used in the
trenches, and since the canister may be used over a period of months before
it is discarded, it is obviously the ultimate activity and capacity (not the
initial efficiency) which determines the value of an absorbent. It must
therefore have a very considerable degree of chemical stability. By this is
meant that the absorbent itself is not subject to chemical deterioration, that
it does not react with carbon dioxide, that it does not disintegrate or become
deliquescent even after being used and that it has no corrosive action on the
metal container.
In a good general absorbent there must be a proper balance between its
various essential qualities, and hence the most suitable mixture will
probably always be a compromise.

Charcoal

The fact that charcoal would condense in its pores or adsorb certain
gases, holding them firmly, had been known for a long time.[28] In general,
it was known that so-called animal charcoal was the best for decolorizing
sugar solutions, that wood charcoal was the best for adsorbing gases and
that coke had very little adsorbing or decolorizing power. No one knew the

reason for these facts and no one could write a specification for charcoal.
The ordinary charcoal used in the scientific laboratory was cocoanut
charcoal, since Hunter had discovered more than fifty years ago that this
was the best charcoal for adsorbing gases.

Raw Materials[29]

The first charcoal designed to offer protection against chlorine and
phosgene was made by carbonizing red cedar. Since this had little value
against chloropicrin, attention was turned to cocoanut shell as the source of
raw material. This charcoal fulfilled the above conditions for a satisfactory
absorbent better than any other form tested. It must not be supposed,
however, that investigation of carbon stopped with these experiments. In the
search for the ideal carbon, practically almost every hard vegetable
substance known was tested. Next to cocoanut shells, the fruit pits, several
common varieties of nuts abundant in the United States, and several tropical
nuts (especially cohune nuts), were found to make the best carbon. Pecan
nuts, and all woods ranging in hardness from iron wood down to ordinary
pine and fir, were found to be in the second class of efficiency. Among other
substances tested were almonds, Arabian acorns, grape seeds, Brazil nut
husks, balsa, osage orange, Chinese velvet bean, synthetic carbons (from
coal, lamp-black, etc.), cocoa bean shell, coffee grounds, flint corn, corn
cobs, cotton seed husks, peanut shells and oil shale. While many of these
substances might have been used in an emergency, none of them would
produce carbon as efficient, volume for volume, as that of the cocoanut
shell and other hard nuts.
Some idea of the scale of charcoal production may be seen from the
requirement for cocoanut shells. When we first began to build masks our
demands for carboniferous materials ranged from 40 to 50 tons a day of raw
material; by the end of the war, we were in need of a supply of 400 tons of
cocoanut shells per day. This demand would absorb the entire cocoanut
production of tropical America five times over. (The total production of
cocoanuts in Central America, the West Indies and the Caribbean Coast of
South America amounted to 131,000,000 nuts annually, equal to a supply of
75 tons of shells daily.) It was equal to one-tenth of the total production of
the Orient, which amounted to 7,450,200,000 nuts annually. This large

demand always made a reserve supply of charcoal material practically
impossible. The “Eat More Cocoanut” campaign started by the Gas Defense
more than doubled the American consumption of cocoanut in a brief space
of time and in October, 1918, with the help of importation of shell, we
averaged about 150 tons of shells per day, exclusive of the Orient.
The first heating of cocoanut shells to make charcoal reduces their
weight 75 per cent. It was evident, therefore, that we could more
economically ship our oriental supply in the form of charcoal produced on
the other side of the Pacific Ocean. A charcoal plant was established in the
Philippine Islands and agents were sent to all parts of the Oriental countries
to purchase enormous supplies of shells. While the work was only gaining
momentum when the Armistice was signed, the plant actually shipped 300
tons of cocoanut shell carbon to the United States and had over 1000 tons
on hand November 11, 1918.
In the search for other tropical nuts, it was found that the cohune or
corozo nut was the best. These nuts are the fruit of the manaca palm tree.
They grow in clusters, like bananas or dates, one to four clusters to a tree,
each cluster yielding from 60 to 75 pounds of nuts. They grow principally
on the west coast of Central America in low, swampy regions from Mexico
to Panama but are also found along the Caribbean coast. The chief virtue of
the cohune nut from the charcoal point of view was its extreme thickness of
shell; this nut is 3 inches or more in length and nearly 2 inches in diameter
but the kernel is very small. Four thousand tons per month were being
imported at the time of the Armistice. A disadvantage in the use of cohune
nuts was that their husks contained a considerable amount of acid which
rotted the jute bags and also caused the heaps of nuts to heat in storage.
A third source of tropical material was in the ivory nuts used in
considerable quantities in this country by the makers of buttons. There is a
waste of 400-500 tons per month of this material, which was used after
screening out the dust. This material is rather expensive, because it is
normally used in the manufacture of lactic acid.
Another great branch of activity in securing carbon supplies was
concerned with the apricot, peach and cherry pits and walnut shells of the
Pacific Coast. A nation-wide campaign on the part of the American Red
Cross was started on September 13, 1918. Between this time and the

Armistice some 4,000 tons of material were collected. Thus the slogan
“Help us to give him the best gas mask” made its appeal to every person in
the United States.

A Theory of Charcoal Action

It has been pointed out that the first charcoal was made from red cedar.
While this was very satisfactory when tested against chlorine, it was of no
value against chloropicrin. In order to improve the charcoal still further it
was desirable to have some theory as to the way charcoal acted. It was
generally agreed that fine pores were essential. The functioning of charcoal
depends upon its adsorptive power and this in turn upon its porosity. The
greater the ratio of its surface to its mass, that is, the more highly developed
and fine grained its porosity, the greater its value. Another factor, however,
seemed to play a rôle. As a pure hypothesis, at first, Chaney assumed that
an active charcoal could only be secured by removing the hydrocarbon
which he assumed to be present after carbonization. Being difficultly
volatile, these hydrocarbons prevent the adsorption of other gases or vapors
on the active material. To prove this, red cedar charcoal was heated in a
bomb connected with a pump which drew air through the bomb. Although
the charcoal had been carbonized at 800°, various gases and vapor began to
come off at 300°, and when cooled, condensed to crystalline plates.
This experiment not only proved the existence of components
containing hydrogen in the charcoal, but also showed that one way of
removing the hydrocarbon film on the active carbon was to treat with an
oxidizing agent.
In the light of the later experimental work Chaney feels that there are
two forms of elementary carbon—“active” and “inactive”; the active form
is characterized by a high specific adsorptive capacity for gas while the
inactive form lacks this property. In general the temperature of formation of
the active form is below 500-600° C. The form is easily attacked by
oxidizing agents—while the latter is relatively stable. The combination of
active carbon with an adsorbed layer or layers of hydrocarbon is known as
“primary” carbon. Anthracite and bituminous coal are native primary
carbons, while coke contains a considerable amount of inactive carbon,
resulting from the decomposition of hydrocarbon during its preparation.

Preparation of Active Charcoal

“On the basis of the above discussion, the preparation of active charcoal
will evidently involve two steps:
“First.—The formation of a porous, amorphous base carbon at a
relatively low temperature.
“Second.—The removal of the adsorbed hydrocarbons from the primary
carbon, and the increase of its porosity.
“The first step presents no very serious difficulties. It involves, in the
case of woods and similar materials, a process of destructive distillation at
relatively low temperatures. The deposition of inactive carbon, resulting
from the cracking of hydrocarbons at high temperatures, must be avoided.
The material is therefore charged into the retorts in thin layers, so that the
contact of the hydrocarbon vapors with hot charcoal is avoided as much as
possible. Furthermore, most of the hydrocarbon is removed before
dangerous temperatures are reached. A slight suction is maintained to
prevent outward leaks, but no activation by oxidation is attempted, as this
can be carried on under better control and with less loss of material in a
separate treatment.

Fig. 67. Dorsey Reactor
for Activating Cocoanut Charcoal with Steam.

“The second step, that is, the removal of the absorbed hydrocarbons
from the primary carbon, is a much more difficult matter. Prolonged
heating, at sufficiently high temperatures, is required to remove or break up
the hydrocarbon residues. On the other hand, volatilization and cracking of
the hydrocarbons at high temperatures is certain to produce an inactive form
of carbon more or less like graphite in its visible characteristics, which is

not only inert and non-adsorbent, but is also highly resistant to oxidation.
The general method of procedure which has yielded the best results, is to
remove the adsorbed hydrocarbons by various processes of combined
oxidation and distillation, whereby the hydrocarbons of high boiling points
are broken down into more volatile substances and removed at lower
temperatures, or under conditions less likely to result in subsequent
deposition of inactive carbon. Thin layers of charcoal and rapid gas currents
are used so that contact between the volatilized hydrocarbons and the hot
active charcoal may be as brief as possible. In this way cracking of the
hydrocarbons at high temperature, with consequent deposition of inactive
carbon, is largely avoided.
“While the removal of the hydrocarbons by oxidation and distillation is
the main object of the activation process, another important action goes on
at the same time, namely, the oxidation of the primary carbon itself. This
oxidation is doubtless advantageous, up to a certain point, for it probably at
first enlarges, at the expense of the walls of solid carbon, cavities already
present in the charcoal, thus increasing the total surface exposed. Moreover,
the outer ends of the capillary pores and fissures must be somewhat
enlarged by this action and a readier access thus provided to the inner
portions of the charcoal. However, as soon as the eating away of the carbon
wall begins to unite cavities, it decreases, rather than increases, the surface
of the charcoal, and a consequent drop in volume activity, that is in the
service time, of the charcoal, is found to result.
“It is obvious, therefore, that conditions of activation must be so chosen
and regulated as to oxidize the hydrocarbons rapidly and the primary carbon
slowly. Such a differential oxidation is not easy to secure since the
hydrocarbons involved have a very low hydrogen content, and are not much
more easily oxidized than the primary carbon itself. Furthermore, most of
the hydrocarbons to be removed are shut up in the interior of the granule.
On the one hand, a high enough temperature must be maintained to oxidize
the hydrocarbons with reasonable speed; on the other hand, too high a
temperature must not be employed, else the primary carbon will be unduly
consumed. The permissible range is a relatively narrow one, only about 50
to 75°. The location of the optimum activating temperature depends upon
the oxidizing agent employed and upon other variables as well; for air, it

has been found to lie somewhere between 350 and 450°, and for steam
between 800 and 1000°.
“The air activation process has the advantage of operating at a
conveniently low temperature. It has the disadvantage, that local heating
and an excessive consumption of primary carbon occur, so that a drop in
volume activity results from that cause before the hydrocarbons have been
completely eliminated. As a consequence, charcoal of the highest activity
cannot be obtained by the air activation process.”
The steam activation process has the disadvantage that it operates at so
high a temperature that the regulation of temperature becomes difficult and
other technical difficulties are introduced. It has the advantage that local
heating is eliminated. The hydrocarbons can, therefore, be largely removed
without a disproportionate consumption of primary carbon. This permits the
production of a very active charcoal.
It has the further advantage that it worked well with all kinds of
charcoal. Inferior material, when treated with steam, gave charcoal nearly
as good as the best steam-treated cocoanut charcoal. Because of the
shortage of cocoanut, this was a very important consideration.

Fig. 68.—Section of Raw Cocoanut Shell.
Magnified 146½ diameters.

The air, steam and also carbon dioxide-steam activation processes have
all been employed on a large scale by the Chemical Warfare Service for the
manufacture of gas mask carbon.

Fig. 69.—Section of Carbonized Cocoanut Charcoal.
Magnified 146½ Diameters.

Fig. 70.—Two-Minute Charcoal not Activated.
Magnified 732 Diameters.
“The above considerations are illustrated fairly well
by the photo-micrographs shown in Figs. 68 to 71. Fig.
68 shows a section of the original untreated cocoanut
shell crosswise to the long axis of the shell. In it can be
seen the closely packed, thick-walled so-called ‘stone-
cells’ characteristic of all hard and dense nut shells. Fig.
69 is a photograph of a similar section through the same
cocoanut shell after it has been carbonized. As these
photographs are all taken with vertical illumination
against a dark background, the cavities, or voids, and
depressions all appear black, while the charcoal itself
appears white. It is clear from this photograph that much
of the original grosser structure of the shell persists in the
carbonized products. Figs. 70 and 71 are more highly
magnified photographs of a carbonized charcoal before
and after activation, respectively. As before, all the dark

areas represent voids of little or no importance in the
adsorptive activity of the charcoal, while the white areas
represent the charcoal itself. In Fig. 70 (unactivated) the
charcoal itself between the voids it seen to be relatively
compact, while in Fig. 71 (activated) it is decidedly
granular. This granular structure, just visible at this high
magnification (1000 diameters), probably represents the
grosser porous structure on which the adsorption really
depends. These photographs, therefore, show how the
porosity is increased by activation.”

Fig. 71.—31-Minute Steam Activated Charcoal.
Magnified 732 Diameters.

The great demand for charcoal, and the need for activating other than
cocoanut charcoal led to the development of the Dressler tunnel kiln, which
seemed to offer many advantages over the Dorsey type of treater.