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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 
 
 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 
 
IJQ. 
 
 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 follow- 
 ing 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 to-day. 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. 
 
 vii 
 
viii PREFACE 
 
 It should be explained that this is in no sense a complete 
 historical sketch of the development and personnel of the Chem- 
 ical 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 accomplish- 
 ments 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 pre- 
 sent 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 recog- 
 nize 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 construc- 
 tive criticisms. Many of the figures are reproduced by permis- 
 sion of the Journal of Industrial and Engineering Chemistry; 
 those showing the Nelson cell were furnished by the Samuel M. 
 Green Company. 
 
 Amos A. Fries, 
 Aug. 1, 1921. Clarence J. West. 
 
FOREWORD 
 
 After all peaceful means of settling disputes between nations 
 have been resorted to and have failed, war is often declared J)y 
 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 a'dversary 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 w^ould be more disastrous. 
 
 Notwithstanding the fact that gas was used in the World 
 War two years before the United States entered the fray, prac- 
 tically 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 
 
X FOREWORD 
 
 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 
 
 ^. Carbon Monoxide 190 
 
 (Xll. 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 
 
 JQQ^The Pharmacology of War Gases 353 
 
 /Hemical Warfare in Relation to Strategy and Tactics . . . 363 
 
 [II. ^HE Offensive Use of Gas 385 
 
 ^ 'Defense against Gas 405 
 
 ^^^,^EACE Time Uses of Gas. 427 
 
 !VI,--The Future of Chemical Warfare 435 
 
 Index 440 
 
CHEMICAL WARFARE 
 
 CHAPTER I 
 THE HISTORY OF POISON GASES ^ 
 
 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 Eng- 
 land, and by England rejected as too horrible to be entertained 
 even for use against an enemy." But the use of poison gases 
 is e ven,^JL an=«arlier-t)rigin"ttign 4to _ ai'tiel e-^alaiins. 
 
 The first recorded effort to overconie an enemy by the genera- 
 tion 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 Bclium, the Spartans saturated 
 wood with pitch and sulfur and burned it under the waPs 
 of these cities in the hope of choking the defenders and rendering 
 the assault less difficult. Similar jiscs-_ of-jKdsonous gases are 
 recor ded during the Middle AgesT In effect they^wefe 
 our modernlTmk baTTs, 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 
 ^Tbis chapter originally appeared in Science, Vol. 49, pp. 412-417 (1919). 
 
2 CHEMICAL WARFARE 
 
 appe8He<J ill th^ 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 cap- 
 tain 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; an^d, 
 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 super- 
 intend 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 
 
THE HISTORY OF POISON GASES 3 
 
 material, though first elevated by heat, soon fell to the ground, destroy- 
 ing 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 Sebas- 
 topol: 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 suffjcient. 
 
 " '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 
 
4 CHEMICAL WARFARE 
 
 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 Play- 
 fair 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 un- 
 doubtedly be produced ; but that those effects were so horrible that no 
 'l 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 im- 
 properly 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.^ 
 
 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 
 
 ^Popular Science Review, 3, 176 (1864). 
 
THE HISTORY OF POISON GASES 5 
 
 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 tliese things be? 1 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-skep^ than to let down 
 on them another host to break their ban^ tea^ tli^ir 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 thi s^ 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 sug- | 
 
6 CHEMICAL WARFARE 
 
 gested 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 iu 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 them- 
 selves 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 sup- 
 
 posed shells was equally uttered previously against fire-arms and tor- 
 I pedoes, although both are now employed without scruple. It is illogical 
 i 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 
 
 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 
 
THE HISTORY OF POISON GASES 7 
 
 penetrate through the narrow slits used for loopholes. The men 
 who were serving the machine guns or the cannon of the flanking 
 Avorks 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 fortifica- 
 tion. 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,^ 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- 
 niask 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 arrange- 
 ment, 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 
 ^ Trans. Boyal Scottish Soc. Arts, 4, Appendix O, 198 (1854). 
 
8 CHEMICAL WARFARE 
 
 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 deo- 
 dorizing 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 contem- 
 poraneously 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; more- 
 over, 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 effec- 
 tually as it does sulphuretted hydrogen or hydrosulphuret of ammonia, 
 and thus prevent their reaching and poisoning the blood. The intention 
 
THE HISTORY OF POISON GASES 9 
 
 accordingly is that those who are exposed to noxious vapors, or com- 
 pelled 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. Sten- 
 house's instrument during their intercourse with the sick. 
 
 "5. The longing for a short and decisive war has led to the inven- 
 tion 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, ^hen 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 prepara- 
 tion 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 w^as planning to poison their enemy 
 with a cloud of gas, and that the cylinders had already been 
 
 10 
 
MODERN DEVELOPMENT OF GAS WARFARE 11 
 
 installed in the trenches. No one listened^to^ the story, becau se, 
 first of all, the whole procedure seemed so impossible and also 
 because, in spite of the numerous examples of German bar- / 
 barity^ Jhe JEnglish 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 informa- 
 tion 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: i^^l 
 
 = — ^^^K^. 
 
 "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 gi'ound and slowly move down wind towards them, the vapor 
 
 cHnging 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." " 
 
 IMs j)nlyjto_be expected t hat the first feeling-conneeted 
 with gas warfare wag. jine_ol harror. That side of it is very 
 thrillingly described by Rev. 0. S. Watkins in the MetJwdist 
 Recorder (London). After describing the bombardment of 
 tlie City of Ypres from April 20th to 22nd he relates that in 
 the midst of the uproar came the poison gas! 
 
 "Going into the open air for a few moments' relief from the 
 stifling atmosphere of the wards, our attention was attracted hy very 
 heavy firing to the north, where the line was held by the French. 
 Evidently a Jiot fight — and eagerly we scanned the country with our 
 
12 
 
 CHEMICAL WARFARE 
 
 <"• flj I 
 
MODERN DEVELOPMENT OF GAS WARFARE 13 
 
 field glasses hoiking to glean some knowledge of the progress of the 
 battle. Then we saw that which ahuost 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. 5iQ_iuman -^ 
 courage coul d 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 coparades. The impossible 
 was only too true. 
 
 ^ It was the most fiendish, wick ed t hing I have ever seen.' 
 
 J 
 
 ^ It must_be said here, however, that this w as true only 
 nccause 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. Medica l 
 records show that_o ut of e very, JOO Aniericans g assed less tha n 
 two died, and as far as records of four years show, very few 
 are permanently injured. O ut of every 100 American cas ualties 
 from all forms of warfare other than g as more than 25 
 per cent died, whilp from 2 to 5 por ^^^it morp arp main i(.^rl, 
 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 kil l. 
 
 Thus instead of gas warfare being the most horrible,Jt 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 ^ay 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 
 
 
14 CHEMICAL WARFARE 
 
 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 hexameth- 
 
 jylenetetramine. This helmet was used until the Standard Box 
 (Kespirator was developed by the late Lt. Col. Harrison. 
 
 Allies Adopt Gas 
 
 For a week or two the Allies were very hesitant about adopt- 
 ing 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 war- 
 fare, they realized there was no choice on their part and 
 that they had to retaliate in like manner. This^ jLecision was 
 reached in May of 1915. It was followed by the organization 
 of a Gas Service and intensive work on the part of chemists, 
 ^:«4^neers and physiologists. It was September 25, 1915, how- 
 eveV, before the English were in a position to render a gas 
 attacK. From then on the Service grew in numbers and in 
 impori^ance, whether viewed from the standpoint of research, 
 produc'L^ion, or field operations. 
 
 The iVllies of course adopted not only chlorine but phosgene 
 as well, si Qce both were cheap, easy of preparation and effective. 
 They felt during the early part of the War that they should 
 adopt a fjubstance 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 Avork was carried out 
 
MODERN DEVELOPMENT OF GAS WARFARE 15 
 
 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 mix- 
 tures 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 recommenda- 
 tion 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 sonie 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 w^ar-lhe mask 
 indefinitely, with an expenditure of shell far short of that 
 required ifjthe 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 valu- 
 able. So great is the harassing value of tear and irritant gases 
 
16 CHEMICAL WARFARE 
 
 that the next war will see them used in quantities approxi- 
 mating 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 bromoace- 
 tone are also well known lachrymators, though they are expen- 
 sive 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 ibdoacetate. This was used with or without 
 the addition of alcohol. Later the French developed bromo- 
 benzyl 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 im- 
 portant 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 
 
MODERN DEVELOPMENT OF GAS WARFARE 17 
 
 required and to the unusual activity behind the lines that became, 
 Avith 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 \^ 
 flaking 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 tliat the only thing neces- 
 sary 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 
 
18 CHEMICAL WARFARE 
 
 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 ^hell 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 AVar, 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 (in- 
 vented 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 pro- 
 jector 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. 
 
 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 
 
MODERN DEVELOPMENT OF GAS WARFARE 
 
 19 
 
 in the rear. The digging in of the projectors in No Man's 
 Land or very close to it was a dangerous and laborious under- 
 taking. The Americans early conceived the idea that pro- 
 jectors 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 
 
 
 ' mi '^"&^'^^-i''^dM^' 
 
 '' 
 
 ** ■ ?^• 
 
 Jfl^^^^^Hj 
 
 ^ 
 
 
 
 
 iCi 
 
 ^r % \ 
 
 
 
 
 
 
 *»* • 
 
 
 Fig. 2. — Livens' Projector. 
 
 The Type shown is an 18 cm. German Gas Projector, captured during the 2d Battle 
 
 of the Mar ne. 
 
 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 neces- 
 sary to so greatly scatter a large projector attack that the 
 
20 CHEMICAL WARFARE 
 
 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 arrange- 
 ment a projector attack could be prepared and launched in 
 two to four hours, depending upon the number of men avail- 
 able. 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 impos- 
 sible 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 rela- 
 tively 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 gradu- 
 ally fell off in number — the true poison gas shell taking their 
 place. Towards the end of 1915 Auld states that the Germans 
 
MODERN DEVELOPMENT OF GAS WARFARE 21 
 
 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 per- 
 sistent. In spite of the fact that American chemists were not 
 able to manufacture superpalite on a large scale, or at least 
 
 Fig. 3.- .Stokes' ^lortur. 
 
 SO successfully that it would compete in price with other Avar 
 gases, the Germans used large quantities of it, alone and 
 mixed with chloropierin, in shell of every caliber up to and 
 including the 15 cm. Howitzer. 
 
 Chloropicrin \ 
 
 The next gas to be introduced was chloropicrin, trichloro- 
 nitromethane or ''vomiting gas." It has been stated that 
 a mixture of chloropicrin (25 per cent) and chlorine (75 per 
 
22 CHEMICAL WARFARE 
 
 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 lachry- 
 matory, but it was mainly used because of its peculiar property 
 of causing vomiting when inhaled. Its value was further in- 
 creased 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 Ger- 
 mans 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 
 
 / 
 
MODERN DEVELOPMENT OF GAS WARFARE 23 
 
 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 suc- 
 cessful. 
 
 Lewisite 
 
 It is rather a peculiar fact that so few new chemical com- 
 pounds were used as war gases. Praxrdcally all X^e. substances 
 were well known to tbe^ organic, chemist .lQn^_bef ore 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 prop- 
 erties, 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. 
 
CHEMICAL WARFARE 
 
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MODERN DEVELOPMENT OF GAS WARFARE 
 
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28 CHEMICAL WARFARE 
 
 (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 thor- 
 oughly 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 
 
MODERN DEVELOPMENT OF GAS WARFARE 
 
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30 
 
 CHEMICAL WARFARE 
 
 TABLE III 
 German Shell 
 
 Name of Shell 
 
 Shell Filling 
 
 Nature of 
 Effect 
 
 B-shell [Ki shell (White B or BM)] 
 
 Bromoketone (B r o m o - 
 methylethyl ketone) 
 
 Lachrymator 
 
 Blue Cross 
 
 (a) Diphenylchloroarsine 
 (6) Diphenylcyanoarsine 
 (r) Diphenylchloroarsine, 
 Ethyl carbazol 
 
 
 
 Sternutator 
 
 C-shell (Green Cross) (White C) . . 
 
 Superpalite 
 
 Asphyxiant 
 
 D-shell (White D) 
 
 Phosgene 
 
 (o) SuperpaUte 
 (6) Phenyl carbylamine 
 chloride 
 
 Lethal 
 
 Green Cross 
 
 Asphyxiant 
 
 
 Green Cross 1 
 
 Superpalite 65%, 
 Chloropicrin 35% 
 
 Asphyxiant 
 
 
 Green Cross 2 
 
 Superpalite, 
 
 Phosgene, 
 
 Diphenylchloroarsine 
 
 
 
 Asphyxiant 
 
 Green Cross 3 (Yellow Cross 1) . . . 
 
 Ethyldichloroarsine, 
 Methyldibromoarsine, 
 Dichloromethyl ether 
 
 Asphyxiant 
 
 K-shell (Yellow) 
 
 Chloromethyl 
 
 chloroformate (Palite) 
 
 Lachrymator 
 AsphyTciant 
 
 T-shell (Black or green T) 
 
 Xylyl bromide, 
 Bromo ketone 
 
 Lachrymator 
 
 Yellow Cross 
 
 Mustard gas, 
 Diluent (CCI4, CfiHsCl, 
 CeHsNOa) 
 
 
 
 
 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. '* Offen- 
 sive 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 amal- 
 gamated 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 increas- 
 ing importance of the use of gas in the war (Auld)." 
 
 At once the accumulation of valuable information and ex- 
 perience 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 appre- 
 ciated. When the United States declared war on Germany 
 April 6, 1917, there were a few scattered observations on gas 
 
 31 
 
32 CHEMICAL WARFARE 
 
 warfare in various offices' of the different branches, but there 
 was no attempt at an organized survey of the field, while abso- 
 lutely 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 prepared- 
 ness was discussed, and especially the manner in which the 
 Bureau could be of most immediate assistance with its per- 
 sonnel 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 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 33 
 
 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 BuitcH's great 
 tact, his knowledge of every branch of research under investi- 
 gation 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 
 lal)oratory in Washington to co-ordinate the various activities 
 and also to considerably enlarge those activities under the 
 joint direction of tlie 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 otlier 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 Edge- 
 wood 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 
 
34 CHEMICAL WARFARE 
 
 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 Depart- 
 ment, 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 Over- 
 seas 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 per- 
 sonnel, inchiding 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 author- 
 ized 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 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 35 
 
 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 commis- 
 sioned 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 Sec- 
 tion. 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 activi- 
 ties, 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 direc- 
 tion 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 Colond W. J. Lyster 
 
 Proving Lt. Col. W. S. Bacon 
 
 Administration Brigadier General H. C. Newcomer 
 
 Gas and Flame Colonel E. J. Atkisson 
 
36 CHEMICAL WARFARE 
 
 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 regi- 
 ments 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 depart- 
 ment 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 ow^n 
 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 develop- 
 ment which has been sketched in the preceding pages. It is 
 not necessary to revicAV that, but the organization as of October 
 19, 1918 will be given: 
 
 Director Major General Wm. L. Sibert 
 
 Staff: 
 
 Medical Officer Colonel W. J. Lyster 
 
 Ordnance Officer Lt. Col. C. B. Thurnrael 
 
 British Military Mission Major .J. H. Brightman 
 
 A.ssistant Director Colonel H. C. N 
 
 ewcomer 
 
 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. 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 37 
 
 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 ii^dustries were enabled to retain, on deferred classi- 
 fication or on indefinite furlough, those skilled chemists with- 
 out 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 Sec- 
 tion was to secure the order from The Adjutant General, dated 
 May 28, 1918, that read: 
 
 "Owing to the needs of tlie mihtary 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 emj loved on chemical duties. . . ." 
 
 While this undoubtedly created a great deal of feeling 
 among the men who naturally were anxious to see actual fight- 
 ing 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, there- 
 
38 CHEMICAL WARFARE 
 
 fore, ordered back to the line, and 1,294 now placed in actual chemical 
 work. There were being held for further investigation of their qualifica- 
 tions on August 1, 1918, 432 men. The remaining 23 men were 
 unavailable for transfer, because they had already received their over- 
 seas 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 Govern- 
 ment 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 cir- 
 cumstances." 
 
 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 labora- 
 tories, 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 i. In Charge of Offense Problems 
 
 * Succeeded Dr. John Johnson who went to the National Research 
 Council. 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 39 
 
 Dr. Reid Hunt Advisor on Pharmacological Problems 
 
 Lt. Col. W. D. Bancroft In Charge of Editorial Work and Cata- 
 
 , lytic Research 
 
 Lt. Col. A. B. Lamb ^ In Charge of Defense Chemical Re- 
 search 
 Dr. L. W. Jones ^ In Charge of Offense Chemical Re- 
 search 
 
 Major A. C. Fieldner In Charge of Gas Mask Research 
 
 Major G. A. Richter In Charge of Pyrotechnic Research 
 
 Capt. E. K. Marshall ' In Charge of Pharmacological Re- 
 search 
 
 Dr. A. S. Loevenhart ' In Charge of Toxicological Research 
 
 Major R. C. Tolman In Charge of Dispersoid Research 
 
 Major W. S. Rowland * In Charge of Small Scale Manufacture 
 
 Major B. B. Fogler * In Charge of Mechanical Research 
 
 and Development 
 
 Captain G. A. Rankin In Charge of Explosive Research 
 
 Major Richmond Levering In Charge of Administration Section 
 
 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 .com- 
 pounds as seemed promising (Small Scale). 
 
 *At first Lt. Col. J. F. Norris was in charge of all chemical research. 
 About December, 1917, it was divided into Offense and Defense, and Lt. 
 Col. Lamb was placed in charge of Defense. When Col. Norris went to 
 England as Liaison Officer, Dr. Jones took his place. 
 
 " In the early organization of the Bureau of Mines, Dr. Yandall 
 Henderson was in charge of the Medical Sciences. Associated with him 
 were Dr. F. P. Underhill, in charge of Therapeutic Research; Major M. C. 
 Winternitz, in Charge of Pathological Research and Captain E. K. Marshall 
 in charge of Pharmacological Research. About May 1, 1918, Phar- 
 macological Research became so extensive that the Section was made into 
 two, with Marshall and Loevenhart in charge, while Dr. Hunt was appointed 
 special adviser on pharmacological problems. When the transfer to the 
 War Department was made, Henderson, Underhill, Winternitz and Marshall 
 were transferred to the Medical Division. 
 
 *Lt. Col. McPherson was formerly in charge, and was later transferred 
 to Ordnance. 
 
 " This Section was originally under H. H. Clark. Later it was split 
 into two, with Clark and Fogler in charge, and finally consolidated under 
 Fogler. 
 
.40 
 
 CHEMICAL WARFARE 
 
 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. 
 
 
 m 
 
 ^ t^*^i 
 
 
 ^3H 
 
 
 /^^Bl 
 
 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 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 41 
 
 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 inspira- 
 tion. 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, lachry- 
 matory 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 Sec- 
 tion ;. 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 tlie Pyrotechnic and Toxicological 
 Sections of the Research Division, to learn the effect when 
 shell loaded with the compound were fired from g-uns on a 
 range, with animals placed suitably in or near the trenches. 
 
42 CHEMICAL WARFARE 
 
 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 advan- 
 tages, 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 lachry- 
 matory. 
 
 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 char- 
 coal, soda lime, and the various mechanical parts of the mask, 
 such as the facepiece, elastics, eyepieces, mouthpiece, nose- 
 clip, hose, can, valves, etc. The story of the ''first twenty- 
 thousand" is very well told by Colonel Burrell.^ 
 
 ^J. Ind. Eng. Chem., 11, 93 (1919). 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 43 
 
 "The First Twenty Thousand 
 
 "About the first of May, 1917, Major L. P. Williamson, acting as 
 liaison oflficer 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 manu- 
 facturers, buckle makers, manufacturers of straps, rubber facepieces, 
 eyepieces, knapsacks, etc. The country w^as 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 Hard- 
 ware Company in St. Louis; facepieces by the Goodrich and Goodyear 
 Rubber Companies at Akron; canisters by the American Can Com- 
 pany; 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 imperme- 
 able 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 appre- 
 ciated at that time by any of the allies, that the gas mask really should 
 
44 CHEMICAL WARFARE 
 
 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 ijroteetion 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 infoimation to the develop- 
 ment 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 Develop- 
 ment 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 iff special in- 
 cendiary materials which were developed for bombs, shells, 
 darts and grenades, and which were later taken over by the 
 
^^^^IJE] 
 
 VELOPMENT OF CHEMICAL WARFARE SERVICE 45 
 
 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. Wlien we entered the war, chlorine, 
 phosgene and choloropicrin 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 diphenylchloro- 
 arsine 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 suc- 
 cessful 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, mag- 
 nesium arsenide, superpalite and bromobenzylcyanide. 
 
 The Chemical Defense Section, organized January, 1918, 
 was occupied with problems relating to protection, such as 
 charcoal, soaa lime, and special absorbents, eyepieces, smoke 
 filters, efficiency of absorbents, and special work with mustard 
 gas. 
 
46 CHEMICAL WARFARE 
 
 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 pen- 
 toxide 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 Sec- 
 tion 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 success- 
 fully as possible under the circumstances, but was dropped 
 when it appeared doubtful if under battlefield conditions of con- 
 centration and length of exposure, any ointment offered suffi- 
 cient 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 experi- 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 47 
 
 mentally, 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 'Svave 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 car- 
 ried 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. Exten- 
 sive studies were also carried out on gas shell linings, from 
 ^vhich 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 con- 
 
48 CHEMICAL WARFARE 
 
 struction 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 success- 
 fully 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 reaUy acted as an emer- 
 gency 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 diffi- 
 culties 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 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 49 
 
 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 pro- 
 duction : 5,692,000 completed gas masks, 3,614,925 of which were 
 
 Fig. 5. — The Defective Gas Mask. 
 
 Successfully us(;d by the Gas Defense Division to stimulate care in every part of the 
 operation of the manufacture of Gas Masks. 
 
 produced at the Long Island City Plant, while the remainder were 
 assembled at the Hero Manufacturing Company's Plant at Phila- 
 delphia, 377,881 horse masks, 191,388 dugout blankets, 2,450 pro- 
 tective suits and 1,773 pairs of gloves, 1,246 tons of protective oint- 
 ment, 45,906 gas warning signals (largely hand horns), 50,549 
 trench fans and many oxygen inhalators. 
 
 The story of the ''first twenty thousand" has already been 
 told on page 43. That these masks were far from satisfactory 
 
50 CHEMICAL WARFARE 
 
 is no reflection upon the men who made them. Even with 
 tlie standard design of the British as a pattern, it was impos- 
 sible 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 Manu- 
 facturing Company of Philadelphia undertook the work and 
 carried on. certain portions of it all through the War. Experi- 
 ence soon showed, however, that because oi 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 NoY. 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 inspec- 
 tion. The personnel was unique in that the authority was 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 51 
 
 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 manu- 
 factured 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 men- 
 tioned 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 produc- 
 tion, 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 build- 
 ing 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 writ- 
 ten, 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 com- 
 menced, requisitions were received for sample lots of oiled 
 mittens and oiled union suits as protection against mustard 
 
52 CHEMICAL WARFARE 
 
 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 valu- 
 able service in pointing out weaknesses of designs as develop- 
 ments 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 neu- 
 tralized 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 Develop- 
 ment 
 
 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 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICER 53 
 
 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 devel- 
 oped, 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 transporta- 
 tion 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 objec- 
 tions 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 equip- 
 ment 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 
 
54 
 
 CHEMICAL WARFARE 
 
 flH 
 
 a 
 
 ^ 
 
 
 
 u 
 
 > 
 
 < 
 
 fe 
 
 TS 
 
 o 
 
 O 
 
 
 o 
 
 Oi 
 
 
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 Qi 
 
 H 
 
 bU 
 
 
 T3 
 
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 W 
 
 t>- 
 
 1 
 
 O) 
 
 1 
 
 
 O 
 
 - 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 55 
 
 ** Gunpowder Reservation," but on May 4, 1918, the name was 
 officially changed to **Edgewood Arsenal." 
 
 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 Edge- 
 wood. 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 und-er 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 millon gallons of salt water and 
 another furnishing' two millions of fresh water daily were suc- 
 cessfully installed. Large power plants were built in connec- 
 tion 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 deriva- 
 tives 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: 
 
56 
 
 CHEMICAL WARFARE 
 
 Production, 
 Pounds 
 
 Shipped in 
 Bulk, Pounds 
 
 Chlorine : 
 
 Liquid 
 
 Gaseous 
 
 Chloropicrin 
 
 Phosgene 
 
 Mustard gas 
 
 Bromobenzyl cyanide . 
 White phosphorus .... 
 
 Tin tetrachloride 
 
 Titanium tetrachloride 
 
 5,446,000 
 2,208,000 
 5,552,000 
 3,233,070 
 1,422,000 
 10,000 
 2,012,000 
 2,012,000 
 362,000 
 
 2,976,000 
 
 3,806,000 
 840,000 
 380,000 
 
 342,000 
 212,000 
 
 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. More- 
 over, 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 com- 
 mercial 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 essen- 
 tial that the work of filling and closing the shell should be 
 
I 
 
 DEVELOPMENT OF CHEMICAL WARFARE SERVICE 57 
 
 clone 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 
 
 Fig. 7. — A Typical Shell-filling Plant at Edgewood Arsenal. 
 
 closing torque was obtained. The final results secured were 
 admirable, as is evidenced by the fact, reported by the Quarter- 
 master 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. 
 
 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 
 
58 
 
 CHEMICAL WARFARE 
 
 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 milli- 
 meters. The approximate amount of toxic gas required for 
 filling each type of shell (10.5 per cent void) is as follows: 
 
 Shell 
 
 Phosgene, 
 Pounds 
 
 N. C.,* 
 Pounds 
 
 Mustard Gas, 
 Pounds 
 
 75 mm 
 
 4 . 7 inch 
 
 1.32 
 
 4.27 
 
 11.00 
 
 22.00 
 
 30.00 
 
 1.75 
 
 6.20 
 
 15.40 
 
 30.30 
 
 1.35 
 4.20 ' 
 
 155 mm 
 
 8 inch 
 
 10.35 
 21.60 
 
 Livens 
 
 
 * N.C. is a mixture of 80 per cent chloropicrin and 20 per cent stannic 
 chloride. 
 
 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 follow- 
 ing figures, representing the number of shell, grenades, etc. 
 
 
 75 mm. Shell 
 
 
 
 
 Filled 
 
 Shipped 
 Overseas 
 
 Phosgene 
 
 2,009 
 427,771 
 155,025 
 
 
 N.C 
 
 300,000 
 150,000 
 
 Mustard gas 
 
 
 Livens Drum 
 
 Phosgene 
 
 25,689 
 
 18,600 
 
 
^^m- DEVI 
 
 DEVELOPMENT OF CHEMICAL WARFARE SERVICE 59 
 Grenades 
 
 White phosphorus 
 Tin tetrachloride . 
 
 440,153 
 363,776 
 
 224,984 
 175,080 
 
 Incendiary Drop Bomb 
 
 Mark I . .... 
 
 542 
 2,104 
 
 
 Mark II 
 
 
 
 
 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. 
 
60 CHEMICAL WARFARE 
 
 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. 
 Lt. Col. Edward M. Ellicott 
 Lt. Col. Wm. C. Gallowhur 
 {Lt. Col. Wm. McPherson 
 Major Adrian Nagelvoort 
 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. WiUiam 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 : 
 
 Commandmg 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 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 61 
 
 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 charter 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 
 bee 1 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 develop- 
 ment of a charcoal suitable for use in gas masks, and its manu- 
 facture. While the details will be given later, it may be men- 
 tioned 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, 
 
62 CHEMICAL WARFARE 
 
 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 absorp- 
 tive 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 con- 
 cerned 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 Edge- 
 wood 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 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 63 
 
 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 ship- 
 ment overseas ; and to prove gas shell, presumably perfect and 
 ready for shipment, to guard against any mechanical inaccura- 
 cies 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. 
 
64 CHEMICAL WARFARE 
 
 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 tvithin 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 correc- 
 tions for ranges, wind velocities, temperatures, ground condi- 
 tions, 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 dis- 
 guising gas bombardments. Gas shell can usually be dis- 
 tinguished by the small detonation on bursting. 
 
 Experiments were performed to determine the decomposi- 
 tion of various gases on detonation. The shell were fired at a 
 
I 
 
 DEVELOPMENT OF CHEMICAL WARFARE SERVICE 65 
 
 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 prob- 
 ably ever be the case in actual battle. These tests gave valu- 
 able 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 incon- 
 spicuous and arduous duty in the face of many local obstacles. 
 
 The Field Training Division of the Gas Defense Service 
 in the United States was organized in September, 1917, and 
 
66 
 
 CHEMICAL WARFARE 
 
 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 were sent to France, while the remainder. 
 
 DIVISIONAL GAS OFFICER 
 
 •i^ 
 
 i^. 
 
 ^4^. 
 
 1 - TRgNCM TAX 
 
 
 i— TEST BOTTLES 
 
 
 J — &A4 ouovta 
 
 ?' 
 
 < i»*oTtcrnrt t.'M »ooT,s 
 
 ^ 
 
 J_OVt«A.l.l. PROT-EtTIVf J.'J'-r 
 
 
 ^ - HCRie • MAin 
 
 
 -J - »<.l.*>XON 
 
 
 6 - r^uHt riTj 
 
 3 - BLf At M!N«r POV*DCR 
 
 ^ 
 
 ,0- I-ILINV CABlX.tr TORtMAmrl 
 
 
 YOU MAOt ME WHAT i AM TO-OAY 
 
 I HOPE YOURE 3ATlsnco 
 
 Fig. 8. 
 
 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 
 w.as often received due to lack of time, many men went into 
 action with no idea of what this training really meant. More- 
 over, an order that the gas officers should not go to France 
 
DEVELOPMENT OF CHEMICAL WARFARE SERVICE 67 
 
 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 assign- 
 ments, the policy was adopted of sending specialized gas officers 
 only to Divisional Camps and the larger training centers. The 
 need of xi 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 Train- 
 ing 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 train- 
 ing, 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 propor- 
 tions 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 
 
68 CHEMICAL WARFARE 
 
 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 trans- 
 ferred 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 con- 
 stantly in mind an ideal of supervised and standardized train- 
 ing 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 
 Underbill, 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, Underbill studied 
 therapy, turning his animals over to Winternitz for pathological 
 
• DEVELOPMENT OF CHEMICAL WARFARE SERVICE 69 
 
 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.^ At Cleveland Sollmann was 
 busy with mustard gas and protective agents. Pearce, work- 
 ing 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^ 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. 
 
 Li the spring of 1918 many of these men were commis- 
 sioned 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 unneces- 
 sary 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 
 
 * See the Pathology of War Gas Poisoning, 1920, Yale Press. 
 
 - See Medical Aspects of Mustard Gas Poisoning, 1919, C. O. Mosby Co. 
 
70 CHEMICAL WARFARE 
 
 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 manu- 
 facture 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 main- 
 taining 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 represen- 
 tations 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 noncommissioned 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 
 
I 
 
 DEVELOPMENT OF CHEMICAL SERVICE WARFARE 71 
 
 training was transferred from the Medical Corps to the 
 P^ngineers, 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 
 di-awn 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. Ilankar 
 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 
 l)eing 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 
 Committer. 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 Expedi- 
 tionary 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 com- 
 mission 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 war- 
 fare 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 
 
 72 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 73 
 
 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 Lie ut. Col. Amos A. Fries, Corps of 
 P^ngineers, Chief of the Gas Ser vice , and requestin g that no 
 assignments to the regiment of gas troops authorized in the 
 United States be made which would conflict with this appoint- 
 ment. On Aug ust 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 pos- 
 sible 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, experi- 
 ments, 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 neeessities 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 organ- 
 ization and for backing it up whenever occasion demanded. 
 Other details of this work will be considered under the follow- 
 ing heads: Administrative; Training; Chemical Warfare 
 Troops ; Supply ; Technical ; Intelligence ; and Medical. 
 
74 CHEMICAL WARFARE 
 
 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 fir^t the Chief of the Gas 
 Service comprised the whole of the Service since he was with- 
 out 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 tlie 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 great- 
 est freedom and willingness, but just as Americans are Ameri- 
 cans 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 hap- 
 pened 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 shoAV some of the difficulties encountered, 
 the following running account is given of some of the early 
 happenings without regard to the sub-divisions 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 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 75 
 
 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 com- 
 plete the draft of tlie 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 com- 
 panies. 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, Head- 
 quarters 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 AVarfare to collect considerable information and a 
 
76 CHEMICAL WARFARE 
 
 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 am- 
 munition 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 pub- 
 lished as G. 0. 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 organiza- 
 tion 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 neces- 
 sary 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 under- 
 taken 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 assign- 
 ment as Chief of the Gas Service twenty thousand American- 
 made masks or box respirators were received from the United 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 77 
 
 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 Britisli 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 inas- 
 much 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 sup- 
 plies through other departments ordinarily handling the same 
 or similar materials. Thus defensive supplies were obtained 
 through the Medical Department and offensive supplies 
 tlirough the Ordnance Department, while other miscellaneous 
 equipment was obtained through the Engineer Department, the 
 Quartermaster Department, or the Signal Corps. This pro- 
 cedure proved exceedingly embarrassing, cumbersome and 
 inefficient. To begin with it was necessary to get some agree- 
 ment 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 
 
78 CHEMICAL WARFARE 
 
 took the attitude that the whole question of obtaining supplies 
 should be left to them, once the requistion 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 offen- 
 sive gas supplies to be purchased from the British were sub- 
 mitted 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 equip- 
 ment 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. Craw- 
 ford 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. 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 79 
 
 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 lOth 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 dif- 
 ficulty 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 
 
80 CHEMICAL WARFARE 
 
 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 bombard- 
 ment 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 mus- 
 tard 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 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 
 
 81 
 
 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 com- 
 plicated as gas in war. 
 
 Training 
 
 Training in Gas Defense. In the latter part of October 
 seventeen young engineer officers, who had just arrived in 
 
 Fig. 9. — Destroying Mustard Gas on the Battle Field. 
 
 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. 
 
 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 
 
82 CHEMICAL WARFARE 
 
 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 anaesthesia, 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 con- 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 83 
 
 tinned 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 an 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. 
 (6) That there must be clear vision and that experience to date 
 indicated that the Tissot method of bringing the inspired air 
 over the eye pieces was by far the best, (c) That the mask 
 must be as comfortable as compatible with reasonable protec- 
 tion, 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 /L^ 
 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 
 •ations. Lewis submitted two brief reports covering facts 
 earing on the use of gas and smoke by the Germans. These 
 reports exiiibited sucli a grasp of gas and smoke battle tactics 
 
 ~ D( 
 
84 CHEMICAL WARFARE 
 
 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 con- 
 tained in Intelligence dispatches and the newspapers, a cable- 
 gram 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- CHEMICAL WARFARE SERVICE IN FRANCE 85 
 
 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 impos- 
 sibility 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 thiBse experiences with mask develop- 
 ment, 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 labora- 
 tory standards. It is difficult for laboratory workers to realize 
 that battle conditions always require a compromise between 
 perfection and getting sometliing in time for the battle. It 
 was early evident to the Gas Service in France that we were 
 sing, and would continue to lose, vastly more men through 
 emoval of masks of the British type, due to discomfort and 
 xhaustion, than we would from a more comfortable but less 
 
86 CHEMICAL WARFARE 
 
 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 pro- 
 tection is to stay at home on the farm. The man who cannot 
 balance protection against legitimate risks has no business pass- 
 ing on arms, equipment or tactics to be used at tlie 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 estalilished 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 CHEMICAL WARFARE SERVICE IN FRANCE 
 
 87 
 
 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. 
 
 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 
 
 
 Fig. 11. — German Gas Alarms. 
 
 of the battle on the morning of the attack at the Army Head- 
 quarters 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 (6f German shell 
 dumps captured during the advance reveale^ less than 1 per 
 
 X 
 
88 CHEMICAL WARFARE 
 
 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 Cajnp. The first lot of about 100 officers 
 were sent to France in July, 1918, with only a few days' train- 
 ing, 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. 
 
THE' CHEMICAL WARFARE SERVICE IN FRANCE 89 
 
 Educating the Army in the Use of Gas. As has been 
 remarked before, the Medical Department in starting the manu- 
 facture 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 
 tlu'oughout 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 com- 
 manders of fighting units, this hostility was outspoken and 
 almost violent. 
 
 Much the hardest, most trying and most skillful work 
 lequired 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 
 ^-qthers the results of gas attacks by the Germans, by the British, 
 
90 CHEMICAL WARFARE 
 
 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 
 
 Fig. 12. — A Typical Shell Dump near the Front. 
 
 making gas known that the manufacturer of a new article 
 adopts to make a thing manufactured by him known to the 
 public. 
 
 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 Ameri- 
 can 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 CHEMICAL WARFARE SERVICE IN FRANCE 91 
 
 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 tliat 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 com- 
 manding 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 
 AVarfare 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 defeat- 
 ing the Germans. 
 
92 
 
 CHEMICAL WARFARE 
 
 Chemical Warfare Troops 
 
 Chemical Warfare troops were divided into two distinct 
 divisions — gas regiments and staff troops. 
 
 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 
 
 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. 
 
 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 manu- 
 factured 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 scream- 
 ing machine gun bullets. 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 93 
 
 Think of the intense interest these men must have felt when 
 carrying from the field of battle to the laboratory or experi- 
 mental field, shell loaded with strange and unheard of com- 
 pounds and which might any moment burst and end forever 
 their existence ! Or watch them drilling into a new shell know- 
 ing not what powerful poison or explosive it might contain 
 or what might happen when the drill '^went through 'M 
 
 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 organ- 
 ization made by the General Staff it was decided to recom- 
 mend 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 
 
94 CHEMICAL WARFARE 
 
 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 
 
 Fig. 14. — Receiving and Transmitting Data for Firing Gas Shell while Wearing 
 Gas Masks. Eiattlefield of the Argonne, October, 1918. 
 
 (eighteen companies) was authorized. A further increase to 
 three regiments of six battalions each (a total of iifty-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. 
 
 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 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 95 
 
 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 Univorsity 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 Marae. 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 Chateau-Thierry. 
 
 Two companies of the First Gs^s Regiment would have been 
 ready in 48 hours to put off a projector attack against an 
 
96 CHEMICAL WARFARE 
 
 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 phos- 
 phorus 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 ditjferent 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 every- 
 
THi: CHEMICAL WARFARE SERVICE IN FRANCE 
 
 97 
 
 one 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 
 
 Fig. 15. — Setting Up a Smoke Barrage with Smoke Pots. 
 
 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. 
 
 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 
 
98 CHEMICAL WARFARE 
 
 nearly complete exhaustion the first week, since they fought 
 or marched day and night during nearly the whole time. Tak- 
 ing 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 char- 
 acter of these gas troops. On one occasion where a battalion 
 of infantry was being held up by a machine gun nest, volun- 
 teers were called for. Only two men, both from the gas regi- 
 ment, 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 bat- 
 talion 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 
 J November 14. The value of gas troops was appreciated so 
 (^much that the Second Army asked to have British gas troops 
 y assigned to them since no American gas troops were available. 
 I 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 Regi- 
 ment 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 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 99 
 
 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.^ 
 
 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 excep- 
 tion 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 oflScers 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." , 
 
 ^ Story of the First Gas Rojjiment, James T. Addison. Houghton Mifflin 
 Co., 1919. 
 
100 CHEMICAL WARFARE 
 
 Supply 
 
 As previously stated it was decided early that the Chemical 
 Warfare Service should have a complete supply service includ- 
 ing 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 impera- 
 tive 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 chloro- 
 picrin, 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 war- 
 fare. 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 recom- 
 mend the manufacture and use of chlorine, phosgene, chloro- 
 picrin, 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 sub- 
 mitted to the French and British and written up in final form 
 perscribing the gases above mentioned on October 26. Follow- 
 
THE CHEMICAL WARFARE SERVICE IN fMNjCK \ JjOj.' 
 
 ing 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 cliief of Ordnance. With reference to para- 
 graph 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, 2^ per 
 cent mustard gas, Yz per cent with bromoaeetone and ^2 per cent with 
 smoke material. According to French 75 millimeter steel shells should 
 not be filled with Vincennite more than three months before being 
 iised. No trouble with other gases or other sized shells except that 
 bromoaeetone 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, 2^/^ per cent with mustard gas, Y2 per cent 
 with bromoaeetone and V2 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. 
 
10? _ , ; ; .\ . .^ CHEMICAL WARFARE 
 
 SubparagTaph C. For Surgeon General. With 'reference to para- 
 graph 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, 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 103 
 
 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 
 lialf 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 
 
 Fig. 16 — Troops Advancing Behind a Smoke Barrage (Phosphorus). 
 
 extend its use in artillery shells including even the 3 inch Stokes' 
 mortar. 
 
 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, wi'th 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 equip- 
 ment or buildings for that purpose on hand and none likely 
 to be for months t6 come, Captain Mayo-Smith was assigned 
 to duty under Colonel Crawford, Chief Gas Officer with the 
 
104 CHEMICAL WARFARE 
 
 Line of Communication, in Paris. A site for a mask repair 
 plant was located at Chateauroux, 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 recom- 
 mendations 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 recom- 
 mendation and a cablegram was at once sent to the United States 
 to that effect. The main risason 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 impos- 
 sible to begin the manufacture of chlorine under two years. 
 On the other hand the shipment of chlorine from the United 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 105 
 
 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 
 iised^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 
 tlie 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 
 ii on a large scale. The Inter-allied Gas Conference in Sep- 
 tember, 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 manufac- 
 turing ethylene chlorhydrin, the principal element in the manu- 
 facture 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 
 
106 
 
 CHEMICAL WARFARE 
 
 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 mus- 
 tard gas information then in the hands of the British they 
 \*^ould have received far less information than they already 
 possessed on mustard 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 
 
 PMjM 
 
 
 
 
 
 
 Fig. 17.— ''Who Said G&sT 
 
 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 stibstance 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 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 107 
 
 required the first 75,000 to be delivered December 1, 1917. 
 In reply it was stated that the British could not fnrnish 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 
 fcVery 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 prac- 
 tically no protection against the high concentrations of phos- 
 gene 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, 
 
108 CHEMICAL WARFARE 
 
 became lost and only turned up ^Ye 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 dis- 
 infected 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 neces- 
 sity of w^eakening 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 Sup- 
 ply Service never failed and finally forged to the very fore- 
 front 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 
 
 n\ 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 deci- 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 
 
 109 
 
 sion 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, whicli position he held throughout the war. 
 
 I 
 
 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 impos- 
 sible 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 
 
no CHEMICAL WARFARE 
 
 of technical and chemical work be sent to France. The French 
 authorities said they would put them in any factories, labora- 
 tories or experimental places that the Chief of the Gas Service 
 desired. A second inquiry about these men was sent but never- 
 theless 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 diphenyl- 
 chloroarsine than by pulverizing it in high explosive shell was 
 felt to be serious. The British had just then perfected protec- 
 tion against diphenylchoroarsine 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 diphenylchloro- 
 arsine 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 
 diphenylchlor oar sine. 
 
 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 
 
> 
 
 THE CHEMICAL WARFARE SERVICE IN FRANCE 111 
 
 ►Staff, and a certain number with the gas troops. It was pro- 
 posed 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 
 sliould be composed of men from every walk of life. In three 
 positions out of every four in the field a good personality com- 
 bined with energy, hard work and common-sense count for 
 more than mere technical training. 
 
 Hanlon (Experimental) Field. As early as December 15, 
 917, it was decided that an experimental field in France was 
 ut'cessary, and a letter was written to the General Staff request- 
 ing 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 aban- 
 doned 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 Head- 
 quarters. 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 draw- 
 backs encountered by other Sections of the Gas Service. 
 
il2 CHEMICAL WARFARE 
 
 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 organ- 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 113 
 
 ized 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 ocasional pamphlets and also a weekly gas bulletin. 
 So extensive was the work of this Division that three mimeo- 
 graph machines were kept constantly going. The weekly bul- 
 letin 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 pic- 
 tures 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, develop- 
 ment, 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 Head- 
 
 uarters of the Chemical Warfare Service to the United States 
 
1 14 CHEMICAL WARFARE 
 
 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 2V2 
 years after the British and French, the weekly bulletin and occa- 
 sional 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 betAveen 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 suf- 
 fering from gas alone. These men received a total of 266,112 
 
THE CHEMICAL WARFARE SERVICE IN FRANCE 115 
 
 wounds, of which 88,980, or 33.4 per cent, were gas. Thus 
 ^/a 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 liospitals 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 con- 
 sisted 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 exten- 
 sively 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 require- 
 ments 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: 
 
 (la) 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 concentra- 
 tion 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 elec- 
 trolysis of a salt (sodium chloride) solution. The operation is 
 described below. In 100-pound cylinders, the commercial prod- 
 
 116 
 
CHLORINE 117 
 
 net 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. 
 
 (Set) 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 follow- 
 ing 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 develop- 
 ment 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 
 
118 
 
 CHEMICAL WARFARE 
 
 soon recognized that even with these accessions, large addi- 
 tions 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 
 
 ^fMdl;i _. 1 1,^ 
 
 
 ^^^..^ ,,; 
 
 \,~^ ■• ^^''^'1|^, i 
 
 ^mt^S^K/KM 
 
 
 
 i . _ 
 
 
 H1M«S^B(^~ . --ikbi^^i f j«i^i«^^^ 
 
 Fig. 19. — Chlorine Plant, Edgewood Arsenal. 
 
 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. 
 
 The following description of the plant is taken from an 
 article by S. M. Green in Chemical arid Metallurgical Engineer- 
 ing 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 
 
CHLORINE' 
 
 119 
 
120 CHEMICAL WARFARE 
 
 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, over- 
 flowed 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 containmg 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 deli\ered 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 Avas 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 
 
CHLORINE 121 
 
 gTaphite 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. 
 
 r "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. 
 
122 
 
 CHEMICAL WARFARE 
 
CHLORINE 123 
 
 "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 drjang 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. 
 
 k 
 
 Properties 
 
 Chlorine, at ordinary atmospheric pressure and temper- 
 vature, 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 con- 
 densation 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 com- 
 bination in a large number of compounds. Among the many 
 
124 CHEMICAL WARFARE 
 
 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 man- 
 ufacture 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 prepa- 
 ration. 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 witli 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 reputa- 
 tion 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 
 
CHLORINE 
 
 125 
 
 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 manu- 
 factured 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 
 
 126 
 
PHOSGENE 127 
 
 of 30 minutes, but 0.3 milligram of phosgene will have the same 
 effect. This of course means that a cloud of phosgene contain- 
 ing one-eighth (by weight) of the concentration of a chlorine 
 cloud will have the same lethal properties. 
 
 (5) 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). 
 
 I 
 
 Manufacture 
 
 I 
 
 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 reac- 
 tion is the most economical of these for large scale produc- 
 tion. The reaction is a delicate one, hoAvcver, and its application 
 equired 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 investiga- 
 tions were given to the government and aided considerably in 
 he early work on phosgene at the Edgewood plant. 
 
 Of the raw materials necessary for the manufacture of phos- 
 
128 
 
 CHEMICAL WARFARE 
 
 gene, 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 
 
 Fig. 23. — Furnace for . Generating Carbon Monoxide. 
 
 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 
 
PHOSGENE 
 
 129 
 
 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 
 
 i 
 
 
 l^-i^i/^r*- .^^ rn 
 
 i 
 
 1 
 
 
 1 1 
 
 
 Fig. 24. — Catalyzer Boxes Used in the Manufacture of Phosgene. 
 
 i 
 
 this way a very definite temperature could be maintained, and 
 She production of carbon monoxide was greatly increased. 
 
 Carbon dioxide was prepared by the combustion of coke, 
 he gas was washed and then passed into a solution of potas- 
 sium 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 com- 
 
130 CHEMICAL WARFARE 
 
 plete. 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 pre- 
 pared 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 
 
PHOSGENE 131 
 
 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 hexamethylene- 
 tetramine (urotropine). This reaction furnished the basis of 
 the first protection used by the British. Later the catalytic 
 decomposition of phosgene into carbon dioxide and hydro- 
 chloric acid by tlie 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 V 
 solvent for sneezing gas, the presence of chlorine must he/\ 
 avoided, since it reacts with tlic substance in solution, usually 
 producing a harmless material. Chlorine may be removed from 
 phosgene by passing the mixture through cotton seed oil. 
 
 Protection ( ^ML V \ \ / ^ 
 
 It was mentioned above that hexametnylenetetramine 
 (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 protec- 
 tion against phosgene. In this filling, the charcoal both absorbs 
 the phosgene and catalyzes the reaction with the moisture of 
 the air with which tlie 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 
 
132 CHEMICAL WARFARE 
 
 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 
 
 
 
 
 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, 
 (.0.9 X 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 
 
PHOSGENE 133 
 
 trucks are run by an electric storage battery locomotive to 
 Xhe filling unit. The shell are transferred by hand to a con- 
 veyor, 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 
 
 
 1 
 
 ^^^^^^^^^^^" ,.,^H 1 
 
 ^^ 
 
 
 ^^M '~^r|| 
 
 
 iP! 
 
 WIM 
 
 Fig. 25. — Filling Livens Urums with Phosgene. 
 
 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 con- 
 stant 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. 
 
 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. 
 
134 
 
 CHEMICAL WARFARE 
 J 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 
 
 Fig. 26. — Interior of a Shell Dump. 
 
 superpalite, and phosgene and diphenylchloroarsine have been 
 found. 
 
 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 com- 
 bines 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 
 
PHOSGENE 135 
 
 a mixture of phosgene and pumice stone. A captured projector 
 contained about 13 pounds of phosgene and 51/2 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 proper- 
 ties, phosgene really forms an ideal gas to produce casualties. 
 
 ,^^'M 
 
 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 eon- 
 fusion, forcing the men to move about more or less and prac- 
 tically 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. 
 
 ft 
 
136 CHEMICAL WARFARE 
 
 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. Tlie 
 nearest edge of the village shelled with phosgene was less tlian 
 700 yards from the nearest attacking troops. None of tlic 
 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 ehofiaical warfare is concerned. Lachry- 
 mators are substances which affect the eyes, causing involun- 
 tary 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 
 liave 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 sub- 
 terranean 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 
 
 137 
 
138 CHEMICAL WARFARE 
 
 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 com- 
 mercial 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 bromoace- 
 tone 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 chloro- 
 acetone, which they called "martonite." As the war pro- 
 gressed, 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 
 
tf 
 
 LACHRYMATORS 139 
 
 investigators. This probably is due to the fact that the mono- 
 bromo derivative is mixed with those containing two or more 
 toms of bromine. A sample boiling at 126-127° and melting 
 t —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 detona- 
 tion. 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 bromo- 
 acetone. They regenerated the bromine by the use of sodium 
 chlorate : 
 
 NaClOa + 6HBr ±= NaCl + 3Br2 + SH^O 
 
 [n 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+H2S04+NaC103 = 
 4CH2BrCOCH3+CH2ClCOCH3+NaHS04+3H20. 
 
 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. 
 
140 CHEMICAL WARFARE 
 
 German Manufacture of Bromo acetone and Bromomethylethyl 
 
 KETONE* 
 
 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 Lrs. 
 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 monobromo- 
 ketone. 
 
 It was finally transferred by suction or by pressure into tank- 
 wagons. At first lead-lined tanks were used, but later it was found 
 
 ♦Norris, J. Ijid. Eng. Chem., 11, 828 (1919). 
 
I 
 
 LACHRYMATORS 141 
 
 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 decomposi- 
 tion 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. 
 
 Haloqenated Esters 
 
 The use of ethyl iodoacetate was advocated at a time when 
 the price of bromine seemed prohibitive. Because of the rela- 
 tive 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 bromo- 
 acetone, having a vapor pressure of 0.54 mm. of mercury at 
 20° C. Ethyl iodoacetate is about one-third as toxic as bromo- 
 acetone, but has about the same lachrymatory value. 
 
 Aromatic HALroEs 
 
 '* 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 
 
142 CHEMICAL WARFARE 
 
 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 circum- 
 stances, 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 com- 
 pound. 
 
 Bromobenzyl Cyanide 
 
 Bromobenzyl cyanide is, chemically, a-bromo-a-tolunitrile, 
 or phenyl-bromo-acetonitrile, CgHsCHBrCN. 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 pro- 
 ceed smoothly. The cyanide is subjected to a fractional dis- 
 tillation 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 hydro- 
 bromic acid which is formed is carefully removed by a stream 
 
LACHRYMATORS 143 
 
 fof 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 can- 
 not be distilled, even in a high vacuum. It has a low vapor pres- 
 sure and thus is a highly persistent lachrymator. 
 k 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 men- 
 tioned above is shown in the following table: 
 
 Bromobenzyl cyanide . 0003 
 
 Martonite 0.0012 
 
 Ethyl iodoacetate 0.0014 
 
 Bromoacetone 0.0015 
 
 Xylyl bromide ; . . . 0018 
 
 Benzyl bromide 0.0040 
 
 Bromo ketone . Oil 
 
 Choroacetone 0. 018 
 
 Chloropicrin . 019 
 
 The figures give tlie 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 \ 
 w^ere well known compounds. And likewise, chloropicrin -v^as \ 
 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, CI3CNO2), 
 gave very poor yields. While it may be prepared from ace- 
 tone, 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. 
 
 144 
 
CHLOROPICRIN 
 
 145 
 
 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 
 
 i 
 
 Fig. 27. — Interior of Chloropicrin Plant. 
 
 were tested, of which the simpler form, without .steam jacket or 
 stirrer, proved the more efficient. 
 
 The early work was undertaken at the plant of the Ameri- 
 can 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 
 ith a solution of calcium picrate (picric acid neutralized with 
 
146 CHEMICAL WARFARE 
 
 lime). "When the current of live steam is a,dmitted 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 set- 
 tles 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 wth 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 decom- 
 posed 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 prac- 
 tically 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 
 
CHLOROPICRIN 
 
 147 
 
 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 con- 
 centration 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. 
 
 Cone. 
 
 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 
 
 22 
 20 
 
 oj 16 
 
 5 11 
 
 o 10 
 
 Is 
 
 I. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 • 
 
 Carve 
 
 Snbject 
 
 Eye 
 
 
 — c 
 
 \1 
 
 
 
 
 
 
 
 
 
 
 
 
 UeutEector 
 
 Pvt.ProKr 
 
 Pvt.WhitUe»ej 
 
 Right 
 Left 
 Right 
 Right 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 > 
 
 
 
 . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 « 
 
 
 
 ^\ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 \\ 
 
 , 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ 
 
 'V 
 
 ^^ 
 
 
 • 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 \^ 
 
 
 1 
 
 w 
 
 
 •- 
 
 
 — 
 
 — 
 
 — 
 
 
 
 
 
 
 
 
 
 
 
 
 \. 
 
 . o 
 
 S 
 
 ^ 
 
 ^o-. 
 
 — . 
 
 
 
 
 
 
 
 
 
 ■ 
 
 ) 
 
 
 
 
 
 
 ■^-.. 
 
 er— 
 
 ^ 
 
 
 
 
 ■^■^ 
 
 — ~ 
 
 ~ — 
 
 — ( 
 
 3 
 
 
 
 
 
 
 
 
 
 ! 
 
 
 
 
 r — 
 
 
 ^ 
 
 "^ 
 
 r- 
 
 
 
 
 
 
 2 4 6 8 10 12 14 16 18 20 22 24 2C 28 
 Time In Seconds 
 
 32 34 
 
 Fig. 28. — Calibration Curve of Eyes for Chloropicrin. 
 
 c/ 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. For- 
 
148 CHEMICAV WARFARE 
 
 tunately 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 concentra- 
 tion. 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 hifeh 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 chloro- 
 picrin (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 mix- 
 ture combines the advantages of a gas shell with those of a 
 smoke shell, since tlie percentage of stannic chloride is suffi- 
 
CHLOROPICRIN 149 
 
 ciently 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 neg- 
 ligible 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 chloro- 
 picrin, 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 suffi- 
 ciently high to cause casualties through inhalation of the gas- 
 ladened air. The introduction of ''mustard gas" (dichloro- 
 ethylsulfide) 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 dichloroethysulfide (ClCHgCHg) gS. 
 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 Ger- 
 mans; "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. 
 
 150 
 
MUSTARD GAS" 151 
 
 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 ethyl- 
 ene 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 cor- 
 ctly identify the contents of the first Yellow Cross dud 
 "eceived. 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 recog- 
 ^Hzed by the Germans and they used tremendous quantities 
 ^H it. During ten days of the Fall of 1917, it is calculated that 
 ^Bver 1,000,000 shell were fired, containing about 2,500 tons of 
 ^^ustard gas. Zanetti states that the British gas casualties 
 
 f'^nring the month following the introduction of mustard gas 
 re almost as numerous as all gas casualties incurred during 
 i previous years of the war. Pope says that the effects of 
 istard gas as a military weapon were indeed so de«b|ting 
 it by the early autumn of 1917 the technical advisers of the 
 
152 CHEMICAL WARFARE 
 
 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 atten- 
 tion should be turned to the large scale operation of this 
 method. 
 
 The following operations are involved: Ethylene is pre- 
 pared by the dehydration of ethyl alcohol. The interaction of 
 hypochlorous acid (HCIO) and ethylene yields ethylene 
 chlorhyd in, ClCHsCH^OH. 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: 
 
 CH3CH20H = CH2 : CH2+H2O 
 CH2 : CH2H-HC10 = H0CH2CH,C1 
 2HOCH2CH2Cl+Na2S = (HOCH2CH2)2S+2NaCl 
 (H0CH2CH2)2S-|-2HC1= (C1CH2CH2)2S+2H20 
 
 Without going into the chemistry of this reaction, which 
 is thoroughly discussed by Gomberg^ (see also German Manu- 
 facture), 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 poten- 
 tialities represented by the large German fine chemical fac- 
 tories.' " It is true that a gjreat 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 dichlor- 
 ide. While American chemists were not very successful in their 
 
 ^J. Am. Chem. Soc. 41, 14]4 (1919). 
 
''MUSTARD GAS" 153 
 
 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 Societe 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 pro- 
 ducing close to twenty tons a day. The plant was being dupli- 
 cated 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 (SgClg) at 60°. 
 yielded mustard gas and sulfur: 
 
 2CH2 : CH24-S2Cl2 = (CH2ClCH2)2S-fS 
 
 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 tlie 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. •'* 
 
 It was especially important, therefore, when Green dis- 
 covered 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 
 
154 
 
 CHEMICAL WARFARE 
 
 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., 
 
 f '"' 
 
 . u , -r- — ' ' 
 
 ' 
 
 
 i| ;f4W|'VfMi::iiii 
 
 i 1 < 
 
 II! 1 
 
 Li . -Si ! 
 
 Fig. 29. — Th€ Levinstein Reactor as Installed at Edgewood Arsenal. 
 
 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 
 
''MUSTARD GAS'' 155 
 
 Ijetween 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 demon- 
 strated 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 sueh 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. 
 
156 
 
 CHEMICAL WARFARE 
 
 WW 
 
 c^^ 
 
 
 o 
 
MUSTARD GAS" 
 
 157 
 
 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 
 
 Fig. 31. — Row of Furnaces for the Preparation of Ethylene. 
 
 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. 
 
 In the manufacture of one ton of mustard gas, about one 
 
158 
 
 CHEMICAL WARFARE 
 
 ton of sulfur chloride and a little less than half a ton of 
 ethylene (12,640 cubic feet) are required. 
 
 German Method op Manufacture* 
 
 "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 
 
 Outlet of Ethylene Mixture 
 
 Heating Gas Outlet 
 
 10 Flue Pipe 
 
 A^Back PresBure EeHef 
 
 3Q^ 
 
 Cooling H2O 
 
 3t 
 
 GondeDser Coil 
 
 Inlet Pipe 
 
 Alcohol Vapor 
 
 Inlet Pi 
 
 2-> 
 Steam Jactet Plpe-> 
 
 AX^Condensed 
 Alcohol Outlet 
 
 Fig. 32. 
 
 -Preparation of Ethylene at Badische Anilin und Soda Fabrik. 
 60 units. 
 
 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. 
 "Preparation of Ethylene Chlorhydrin — The reaction was car- 
 ried 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 
 
 * Norris, J. Ind. Eng. Chem., 11, 821 (Sept., 1919). 
 
''MUSTARD GAS' 
 
 159 
 
 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 
 
 Heating Gas 
 Outlet 
 
 k 
 
 
 
 
 J- 
 
 p 
 
 •<: 
 
 
 
 
 
 
 
 3 
 
 •'-lo'Vlue 
 
 ^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 "L"\ 
 
 
 
 N-^ 
 
 Ua 
 
 ^ ^ ^ A 
 
 A 
 
 — fc- 
 
 \. 
 
 C5 
 
 I I 
 
 Jk, ) 
 
 J 
 
 
 
 
 
 
 
 \ 
 
 Alcohol Vapor Inlot Fipoi 
 
 )/ 
 
 
 
 KN03^ 
 Contact 
 
 Etbyleue i:ixturo Ootlct 
 
 1 Copper Coil 
 12 Turus 
 
 Cotl enters Contact' 
 Tube at Base 
 
 Fig. 33. — Ethvlene Production at Badische Anilin imd Soda Fabrik. 1 unit. 
 
 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 
 
 Stbylene Gaa Inlet 
 CO,Inlet 
 
 ^lixing Blades 
 Lead Lined 
 Cotl 
 
 Fump 
 
 To Colli 
 
 ® ) ) and Filter 
 
 Press 
 
 Fig. 34. — Chlorhydrin reaction kettle at Badische Anilin und Soda Fabiik. 
 
 16 units. 
 
 apparatus employed in this factory. The temperature during the 
 reaction varied between 5° and 10°. In order to maintain this tem- 
 perature, the solution was constantly pumped from the apparatus 
 through a coil which was cooled by brine. When ethylene was no longer 
 
160 
 
 CHEMICAL WARFARE 
 
 absorbed and tbere was an excess of carbon dioxide present, the solution 
 was tested for hypochlorous acid. The time required for the introduc- 
 tion 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. 
 
 ©01^ 
 
 Fig. 35. — Mustard Gas Manufacture at Leverkusen. Layout for Chlorina- 
 tion of Thiodiglycol. 
 
 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. 
 "Preparation of Dihydroxyethylsulfide — To prepare the hy- 
 droxysulfide, 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 
 
"MUSTARD GAS" 161 
 
 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 ll^ 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 tlie 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 
 
162 CHEMICAL WARFARE 
 
 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 distilla- 
 tion 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 follov^ing discussion is 
 taken from a report originally made during construction, 
 Sept., 1918. 
 
 The Levinstein reactor consisted of a jacketed and lead- 
 lined vessed or steel tank, 8 feet 5 inches in diameter and 14 
 feet tall. The reactor contained 1,400 feet of lead pipe (out- 
 side diameter 2% 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 v^as introduced through lead injectors, of v^hich 
 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 intro- 
 duced into the reactor to cover the central nozzles. Ethylene 
 was now introduced, and as the reaction proceeded sulfur chlo- 
 ride was added in sufficient quantities to give a high rate of 
 reaction. Brine or cold water was introduced through the 
 
''MUSTARD GAS" 163 
 
 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. f^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 di-awn 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 tem- 
 perature at the close of the reaction from 55° to 70° C. This, 
 liowever, 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 neighbor- 
 hood without being detected through its odors. It still seems 
 
164 
 
 CHEMICAL WARFARE 
 
 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.* 
 
 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 nitro- 
 benzene. 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 folowing table: 
 
 
 Melting-point of 
 
 Mustard gas Mixt 
 
 URES 
 
 Per Cent 
 Added 
 
 Cliloropicrin 
 
 Chlorobenzene 
 
 Carbon 
 Tetrachloride 
 
 
 10 
 20 
 30 
 
 13.4° C. 
 9.8 
 6.3 
 2.6 
 
 13.4° C. 
 
 8.4 
 
 6.4 
 
 -1.0 
 
 13.4° C. 
 9.8 
 6 6 
 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. 
 
 * J. Ind. Eng. Chem., 11, 292 (1919). 
 
''MUSTARD GAS" 165 
 
 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 dihydroxyethyl- 
 sulfide and hydrochloric acid : 
 
 (C1GH2CH2)2S+2H20 = (H0CH2CH2)2S+2HC1 
 
 Certain sulfonated oils accelerate the rate of hydrolysis, both 
 by increasing the rate ol 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. 
 (Pig. 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 mus- 
 tard 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 dichlo- 
 ride. Sulfur chloride on the other hand has no effect on mus- 
 tard gas. Chloramine-T and Dichloramine-T (the valuable thera- 
 peutic agents introduced by Dakin and Carrel for treatment 
 of wounds) also react with mustard gas. For this reason 
 
166 
 
 CHEMICAL WARFARE 
 
 they were advocated as treatment for mustard gas burns. But 
 as we will see later, they were not altogether successful. 
 
 V 
 
 Detection 
 
 At first the only method of detecting mustard gas was 
 through the sense of smell. It was then believed that concen- 
 trations which could not be detected in this way were harm- 
 less. 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 
 
 To Gas Tank 
 
 Fig. 36. — Field Detector for Mustard Gas. 
 
 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 con- 
 sisted 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 posi- 
 tive reaction and often in a shorter time than 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 
 
"MUSTARD GAS'' 167 
 
 ito the bottom of recently captured trenches and if, after a 
 Few minutes, they turned black, the presence of mustard gas 
 -as suspected. It is also stated that the characteristic yellow 
 ^aint on the ogive of the mustard gas shell had the same com- 
 position, 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 pig- 
 ment 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 g^s, 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 exten- 
 
168 
 
 CHEMICAL WARFARE 
 
 sively, both as relates to the toxicity and to the skin or blister- 
 ing 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 
 
 Mustard gas 
 
 Phosgene 
 
 Hydrocyanic acid 
 
 Chloropicrin 
 
 Chlorine 
 
 Dogs 
 
 0.05 
 
 0.1 
 
 0.8 
 3 
 
 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 con- 
 junctivitis and superficial necrosis of the cornea; hyperemia, 
 oedema 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 sub- 
 stance into the blood stream, and its distribution to the various 
 tissues of the body. 
 
 The most striking observation about the symptoms of mus- 
 tard gas poisoning is the latent period which elapses after 
 exposure before any serious objective or subjective effects are 
 
I 
 
 ''MUSTARD GAS" . 169 
 
 oted. 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 
 emporary blindness resulting from mustard gas would not 
 e permanent. Later, as the depth and seriousness of some 
 f 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 
 tlie 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 shelP' 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^ has proposed the following 
 mechanism of the action of mustard gas : 
 
 ^Marshall, Lynch and Smith, J. Pharmacal, 12, 291-301 (1918). 
 
170 CHEMICAL WARFARE 
 
 "Dichlorethysulphide 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 dichlorethysulphide 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 hydrocliloric 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. Stimula- 
 tion of the respiratory center is a well known effect of acid. Convul- 
 sions 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)f=K 
 
I 
 
 ''MUSTARD GAS" 171 
 
 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. Accord- 
 ing 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 care- 
 fully studied and fully described by Warthin and Weller in 
 their book on The Pathology of Mustard Gas. Our observa- 
 tions 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 
 
172 
 
 CHEMICAL WARFARE 
 
 The test made on 84 negroes gave the following results: 
 
 1% 0.01% 
 
 Positive Positive. . . 
 
 Positive Negative . . 
 
 Negative Negative . . 
 
 Questionable Negative. . 
 
 % of Total 
 
 0.0 
 
 15.0 
 
 78.0 
 
 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 cours e none 
 would react to a more dilute one. About 10 per cent of white men 
 
 s 
 
 a 
 
 o 
 
 0.1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Concentration of Mustard Gas Required 
 
 to Irritate the Skin- Subject, A 
 
 Sensitive Individual 
 
 X =Burn (Brythema): ° = Doubtful : o = No Burn: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 *JI 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 <x 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 '< 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 k 
 
 . 
 
 _ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 24 32 40 
 
 Time -Minutes 
 
 64 
 
 FiC. 37. 
 
 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." 
 
 The same individual may also show variations in suscep- 
 tibility 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 bum produced after exercising 
 was more severe. Sweating produced by having the subjects place 
 
MUSTARD GAS' 
 
 173 
 
 tlieir 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 foreami 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 neighborliood 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." 
 
 Species 
 
 Number 
 Tested 
 
 Percentage Positive to 
 
 1 Per 
 
 Cent 
 
 0.1 Per 
 Cent 
 
 0.01 Per 
 Cent 
 
 Horse 
 
 Dog 
 
 Goat 
 
 Rat 
 
 Mouse 
 
 Rabbit... . 
 Guinea-pig 
 Monkey. . . 
 
 1 
 91 
 11 
 10 
 
 7 
 
 2 
 12 
 
 9 
 
 100 
 83 
 55 
 30 
 70 
 
 100 
 33 
 22 
 
 100 
 
 35 
 
 36 
 
 20 
 
 14 
 
 
 
 
 
 
 
 100 
 
 
 
 
 
 
 
 
174 CHEMICAL WARFARE 
 
 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^ 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 circum- 
 stances 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 pre- 
 vented. 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 alter- 
 nately 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 
 
 V. Pharmacol., 13, 1 (1919). 
 
I 
 
 ''MUSTARD GAS" 175 
 
 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 estab- 
 lish 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 con- 
 stitutes 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 dichlorethysulphide 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 epithehal 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 pro- 
 duction 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 
 
176 CHEMICAL WARFARE 
 
 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. 
 fit 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 dan- 
 gerous for a week or ten days, and in still colder weather may 
 be dangerous for a month or longer whenever the weather 
 jwarms 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 inter- 
 fere 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 pro- 
 duce 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 Armentieres 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 
 
"9: 
 
 '^ MUSTARD GAS" 177 
 
 ere numerous other cases on a smaller scale where mustard gas 
 as 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 cer- 
 tainly 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 needed. 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 develop- 
 ment 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 
 
178 CHEMICAL WARFARE 
 
 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 tem- 
 peratures is exceedingly low. This has an important bearing on 
 cylinders and other containers for shipping mustard gas, that is, 
 they need be only strong enought to be safe against handling 
 and not to withstand the high pressure encountered with phos- 
 gene 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 wher- 
 ever 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 artil- 
 lery 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 
 
''MUSTARD GAS" 179 
 
 all the burning effects of mustard gas as well as the discomfort 
 of long wearing of the mask. 
 
 It may confidently be expected that that further develop- 
 ments 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. 
 
X 
 
 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 estab- 
 lish 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 constitutents of the mixture vincennite, early used by the 
 French. This was a mixture of hydrocyanic acid, stannic chlor- 
 ide, 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. 
 
 180 
 
ARSENIC DERIVATIVES 
 
 181 
 
 The compound is very easily decomposed b}^ 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. 
 
 Methyldichloroarsine 
 
 The Germans apparently used ethyldichloroarsine because 
 they had no suitable method for the preparation of methyl 
 
 Fig. 38. — Apparatus for the Manufacture of Methyldichloroarsine. 
 
 dichloroarsine, which is a more satisfactory material. The 
 Chemical Warfare Service developed the following method of 
 preparation of the methyl derivative. Sodium arsenite 
 (NaaAsOg) is prepared by dissolving arsenic trioxide in sodium 
 hydroxide solution. The action of methyl sulfate at 85° C. gives 
 
182 , . .CHEMICAL WARFARE 
 
 disodium methyl arsenite, Na^^CHgAsOa. Sulfur dioxide reduces 
 the arsenite to methyl arsine oxide, CHgAsO, wliich is then re- 
 acted 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 burn- 
 ing 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. 
 mercur}^ 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 diphenylchloro- 
 arsine or sneezing gas. Although this is an old compound (hav- 
 ing 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 inter- 
 action 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 ex- 
 plosive 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, 
 
ARSENIC DERIVATIVES 183 
 
 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 poison- 
 ous 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 ^ 
 
 Diphenylchloroarsine 
 
 ^'This substance (Blue Cross) was a famous gas of the Germans 
 and was made in large quantities. The method used b^ 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 
 diphenychloroarsine. The chemical equations for the reactions will 
 make clearer the st6ps involved. 
 
 CcHfiNaCl -f Na,As03 = CeHsAsOaNaa +NaCl +N2 
 CcHsAsOsNaz +2HC1 =C6H5As03Ho +2NaCl 
 CeHAsOsHj +SO2 +H2O = C6HASO2H0 +H2SO4 
 
 ICeHsNjCl +C6H5As02Na2 = (C6H6)2As02Na +NaCl -f-N^ 
 (C6H6)2As02Na +HCI = (C«H5)2As02H +NaCl 
 2(C6H5)2As02H 4-2SO2 +H2O = [(CeHOzAsbO -f 2H2SO. 
 [(C6H6)2Asl20 +2HC1 =2(C6H5)2AsCl +H2O. 
 "The entire process was carried out at Hochst. The method used at 
 Hochst was as follows : In preparing the diazonium solution, 3 kg. mols 
 ^■pf aniline were dissolved in 3000 liters of water and the theoretical 
 ^B »Norris, J. Ind. Eng. Chem., 11, 825 (1919). 
 
184 CHEMICAL WARFARE 
 
 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 diazomum compounds. A solu- 
 tion 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 matej'ial 
 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° Be. 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° Be. 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 
 
ARSENIC DERIVATIVES 185 
 
 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 = (C6H6)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 Hochst from ethylarsenous oxide 
 which was obtained from the Badische Anilin und Soda Fabrik. 
 
 "Preparation of Ethylarsenous Oxide — The compound was pre- 
 pared 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: 
 
 C2H5CI +Na3As03 = CiHsAsOsNaa +NaCl 
 
 CzH^AsOsNaa +2HC1 = C2H5ASO3H2 +2NaCl 
 
 C2H5ASO3H2 +SO2 +H2O = C2H5ASO2H2 +H2SO4 
 
 2C2H5ASO2H2 = (C2H5AS)20 +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 
 
186 CHEMICAL WARFARE 
 
 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 IV2 
 hrs. During the entire reaction, the contents of the autoclave were 
 vigorously stirred. After all the ethyl chloride had been added, the ma- 
 terial 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 chlo- 
 ride 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 ethylar- 
 senous oxide. 
 
 "Preparation of Ethyldichloroarsine — The compound was pre- 
 pared by treating ethylarsenous oxide with hydrochloric acid. The 
 reaction is as follows: 
 
 C.H5ASO +2HC1 = C2H5ASCI +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 
 
ARSENIC DERIVATIVES 187 
 
 temperature during the reaction must not rise above 95°. When the 
 hydrochloric acid was no longer absorbed and was contained in appre- 
 ciable 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.". 
 
 J *' 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 dis - 
 covery and perfection illustrate the possibilities of^esearch 
 as applied to Chemical Warfare, and points to the need of a 
 permanent organization to carry on such work when the pres- 
 sure 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 unsat- 
 urated 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 re- 
 action 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 valu- 
 
188 CHEMICAL WARFARE 
 
 able 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 mix- 
 ture 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 separa- 
 tion 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 hydro- 
 chloric 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 
 ehlorovinyldichloroarsine, CHCl : CH • AsCla, 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 mem- 
 brane of the nose being attacked and violent sneezing induced. 
 
ARSENIC DERIVATIVES 189 
 
 More prolonged exposure leads to severe pain in the throat 
 and chest. 
 
 The second fraction {/3, ^'-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 chlorovinyldichlo- 
 roarsine, but its irritant properties on the respiratory .system 
 are much more intense. 
 
 The third fraction, p, p', /8"-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. 
 
 r 
 
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 intention- 
 ally 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 mon- 
 oxide 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 dis- 
 sipation 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 dis- 
 comfort, 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 Ger- 
 mans and the English, defective high explosive shell, after pene- 
 trating into enclosed portions of the ship, evolved large quan- 
 tities 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 mon- 
 oxide. Similarly, in mining and sapping work, the carbon mon- 
 oxide liberated by the detonation of high explosives constitutes 
 one of the most serious of the difficulties connected with this 
 
 190 
 
CARBON MONOXIDE 191 
 
 work and necessitated elaborate equipment and extensive mili- 
 tary 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 pre- 
 cludes its removal by physical absorption. 
 
 After extensive investigation two absorbents have been 
 found.^ The first of these consists in a mixture of iodine pent- 
 oxide 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 ab- 
 sorbent was finally supplanted by the more satisfactory oxide 
 absorbent described below. 
 
 The metallic oxide mixture was the direct result of an 
 
 * Complete details of this work may be found in J. Ind. Eiig. Chem., 12, 
 21.3 (1920). 
 
192 
 
 CHEMICAL WARFARE 
 
 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 con- 
 
 Spcc'al Small Spring 
 
 10 Mesh Heavy Iron Screen 
 1 Lajei Cutton Pad 
 
 1^ Mesh Heavy Corrugated 
 Iron Screen 
 
 Light Fine Mesh 
 Coppur Screen 
 
 Heavy Iron Dome Screen 
 IC Mesh 
 
 Fig. 39. — Diagram of Carbon Monoxide Canister, CMA3. 
 
 stituent. 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 
 
CARBON MONOXIDE 
 
 193 
 
 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. 
 Hopcalite acts catalytically and therefore only a layer 
 
 Fig. 40. — Tanks and Press for Small Scale Manufacture of Carbon Monoxide 
 
 Absorbent. 
 
 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 
 
 o used in the Hopcalite canisters. 
 
 The life of this canister was the same irrespective of whether 
 S use was continuous or intermittent. The higher the tem- 
 
 ^^S 
 
194 
 
 CHEMICAL WARFARE 
 
 perature 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, Ihe 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 
 
 Fig. 41. — Navy Head Mask and Canister. 
 
 many tests it was determined that any canister which had gained 
 more than 35 grams above its original weight should be with- 
 drawn. 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. 
 
CHAPTER XI 1 
 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, hand- 
 kerchiefs filled with moist earth, etc. One suggestion w^as 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 Eng- 
 lish mask is known as the Black Veiling respirator and con- 
 
 195 
 
193 CHEMICAL WARFARE 
 
 sisted 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. 
 
 The respirator was adjusted over the mouth and nose, the 
 cotton waste being molded to the shape of the face and the 
 
 Fig. 42. — Early Gas Protection. 
 
 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 
 
DEVELOPMENT OF THE GAS MASK 197 
 
 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 eye-pieces 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; 
 
198 
 
 CHEMICAL WARFARE 
 
 (4) It had a peculiar odor and, when wet, frequently burned 
 the foreheads of the men ; 
 
 (5) It offered practically no protection against lachry- 
 mators. 
 
 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 
 
 
 .«f 
 
 "1 
 
 •^ 
 
 'Qi 
 
 ^ 
 
 A 
 
 ^y 
 
 ^' 
 
 ij 
 
 1 
 
 1 
 
 1 
 
 Fig. 43. — Method of Wearing the 
 P. H. Helmet. 
 
 Fig. 44. — Early Type of Standard 
 (British) Box Respirator (S. B. R.) 
 
 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, 
 
DEVEI^OPMENT OF THE GAS MASK 199 
 
 Harrison, who was almost entirely responsible for the wonderful 
 production of this respirator. 
 
 The respirator (Figure 44) consisted of the canister men- 
 tioned above, which is attached by a flexible tube to a f acepiece 
 or mask. The f acepiece 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 punc- 
 tured or torn, gas-containing air cannot be breathed as long as 
 the nose clip 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, (&) the 
 
200 
 
 CHEMICAL WARFARE 
 
 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 
 
 Fig. 45. — Interior of S. B. R., Showing 
 Cotton Wrapped Nose Chps. 
 
 Fig. 46.— French M-2 Mask. 
 
 rather more difficult with the nose closed, this adds another 
 extremely objectionable feature. 
 
 The lack of ventilation in the facepiece chamber entraps 
 the heat radiating from the face and retains the moisture 
 v/hich 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. 
 
DEVELOPMENT OF THE GAS MASK 201 
 
 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 impreg- 
 nated with various absorbent chemicals. A typical mask was 
 made up of 20 layers of cheese-cloth 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 (NiS04.7 H2O) 
 
 
 11.8 lbs. 
 
 Sodium carbonate (Na2 CO3) 
 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 
 
202 CHEMICAL WARFARE 
 
 the following gases (concentration 1 to 1,000, rate 30 liters 
 per minute) : 
 
 Phosgene * 65 minutes 
 
 Hydrocyanic acid 60 minutes 
 
 Chlorine 60 minutes 
 
 Tissot Mask. The French deserve great credit for their 
 development of the Tissot type mask. This was first issued 
 
 Fig. 47. — Interior View of M-2 
 Mask. 
 
 Fig. 48. — French Artillery Mask, 
 Tissot Type. 
 
 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 mouth- 
 piece and noseclip are lacking. The inhaled air enters the 
 mask from two tubes which open directly under the eyepieces 
 
DEVELOPMENT OF THE GAS MASK 203 
 
 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 respi- 
 rator. 
 
 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 
 ^ X 61/^ X 21/^ 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 
 
204 
 
 CHEMICAL WARFARE 
 
 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 
 
 Fig. 49.— French A. R. S. Mask. 
 
 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. 
 
 The mask or head straps are arranged in the same way 
 
DEVELOPMENT OF THE GAS MASK 205 
 
 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 adjust- 
 able 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 9f 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 (6) an inner removable disc which functioned 
 
206 
 
 CHEMICAL WARFARE 
 
 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 
 
 Fig. 50. — German Respirator. 
 
 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." 
 
DEVEWPMENT OF THE GAS MASK 
 
 207 
 
 fl S 9 rt b 
 I CJ « -< O 
 »-< ei eo ■^' lo 
 
208 
 
 CHEMICAL WARFARE 
 
 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. 
 
 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. 
 
 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. 
 
 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 
 
DEVELOPMENT OF THE GAS MASK 2C9 
 
 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-^0 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. 
 
 I At the entrance of the United States into the war, three 
 es 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 
 
 American Mask 
 
210 
 
 CHEMICAL WARFARE 
 
 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. Aarmy 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. 
 
 Faoepiece. The facepiece of the R. F. K. type Box Respi- 
 rator is made from a light weight cotton fabric coated with 
 pure gum rubber, the finished fabric having a total thickness of 
 approximately ^ inch. The fit of the facepiece is along 
 two lines — first, across the forehead, approximately from tem- 
 ple 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 con- 
 form 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. 
 
^aII the st] 
 
 DEVELOPMENT OF THE GAS MASK 211 
 
 b 
 
 11 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 sucli a way as to insure a gas-tight fit at all 
 points. Because of the great variations in the conformation 
 oL' different heads, this problem is not a simple one. Probably, 
 the simplest type of harness, as well as the one which is 
 tlieoretically 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 
 liold them in their proper positions. 
 
 The discomfort of the earlier types of harness has been 
 lemedied, 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 
 i> still much room for valuable work in developing a harness 
 
 ich will combine greater comfort and safety. The following 
 ints should always be observed in harness design : 
 
 (1) The straps should pull in such a direction that as 
 rge a component as possible of the tension of the strap should 
 
 available in actually holding the mask against the .face. 
 
 (2) The number of straps should be kept to a minimum 
 order to avoid tangling and improper positioning when put 
 
 in a hurry by an inexperienced wearer. 
 Eyepieces. One of the most important parts of the gas 
 ask, from the military point of view, is the eyepiece. The 
 imary requirement of a good eyepiece is that it shall provide 
 minimum reduction in clarity of vision with a maximum 
 gree of safety to the wearer. The clarity of vision may be 
 ffected in one of several ways: (1) by abrasion of the eye- 
 ieces under service conditions; (2) irregularities in the sur- 
 face and thickness of the eyepiece, causing optical dispersion; 
 
212 CHEMICAL WARFARE 
 
 (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 absorp- 
 ing the water which condenses on their surfaces, either by com- 
 bining individual drops into a film which does not seriously im- 
 pair 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 Dbjections 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 cement- 
 ing together a layer of celluloid between two layers of glass.* 
 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 leak- 
 ing gas. 
 
 In the matter of flying fragments, the type of eyepiece con- 
 sisting 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 free- 
 dom 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 
 
 * So-called ' ' Triplex ' ' glass. 
 
DEVELOPMENT OF THE GAS MASK 
 
 213 
 
 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 dis- 
 coloration 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. 
 
 I 
 
 K 
 
 Fig. 54. — American Box Respirator, Showing Improved Rubber Nose Clip. 
 
 The position of the eyepiece is very important ; the total and 
 e binocular fields of vision should be kept at a maximum. 
 Nose-clip. The nose-clip 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 com- 
 rt of the clip was greatly improved by using pads of soft 
 bber and springs giving the minimum tension necessary to 
 elose the nostrils. 
 
214 CHEMICAL WARFARE 
 
 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 speciflcations 
 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 
 
DEVELOPMENT OF THE GAS MASK 
 
 215 
 
 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 com- 
 bination of two factors, — first, the difference in atmospheric 
 
 Fig. 55. — American Type Exhale Valve, Mounted and Unmounted. 
 
 pressure, and second, the tension due to mounting a section 
 which has been cured in the flat over an elliptical opening. 
 
 In order to protect the flutter valve from injury and from 
 contact with objects which might interfere with its proper func- 
 
 Itioning, the later types of valve were provided with a guard of 
 Stamped sheet metal. 
 L 
 
 Canisters 
 
 During the development of the facepiece, as discussed above, 
 le American canister underwent changes in design which have 
 
216 
 
 CHEMICAL WARFARE 
 
 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 
 
 aPatnt( 
 L 
 
 Painted Black all over 
 
 Charcoal 
 
 Fig. 56. — American Canister, Type A. 
 
 integral with the bottom of the container, there being no remov- 
 able 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. 
 
 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 char- 
 coal, developed by the National Carbon Co., and 40 per cent of 
 green soda lime, developed and manufactured by the General 
 
I 
 
 DEVELOPMENT OF THE GAS MASK 217 
 
 Chemical Company, Easton, Pa. The entire volume amounted to 
 660 cc. The early experiments with this volume of absorbent 
 showed that -/g 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 ^/^ soda lime 
 and ^/s 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 ma^k. 
 
 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 intro- 
 duced 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 sep- 
 arate 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 
 
218 
 
 CHEMICAL WARFARE 
 
 f 
 
 this the volume of the absorbent was reduced from 450 cc. to 
 300 CO. It was packed in two layers, ^/g in the bottom and ^/a 
 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 ab- 
 sorbent, a change made to decrease leakage about the top cotton 
 pad. 
 
 Spacer 
 
 Spring 
 Heavy Screen 
 Cotton iLd 
 
 Packing Scr'.en 
 PfJJ Xottoji I i.d 
 
 Screen 
 Check Valve 
 
 Fig. 57.— U. S. Army Canister, Type J. 
 
 The following table shows the relative efficiency of various 
 canisters : 
 
 Chloropicrin .... 
 
 Phosgene 
 
 Hydrocyanic acid 
 Mustard gas .... 
 
 p. p. m. 
 
 1000 
 
 2500 
 
 500 
 
 100 
 
 U.S., 
 TypeH 
 
 770 
 
 85 
 
 70 
 
 1800 
 
 British, 
 S. B. R. 
 
 17 
 54 
 90 
 
 French, 
 A. R. S. 
 
 2 
 
 5 
 
 35 
 
 German 
 
 43 
 
 16 
 
 10 
 
 195 
 
DEVELOPMENT OF THE GAS MASK 
 
 219 
 
 B 
 
220 CHEMICAL WARFARE 
 
 The figures represent time in minutes till the first traces of gas 
 begin to come through. 
 
 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^: 
 
 "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 facepieee 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 con- 
 ducted 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 facepieee 
 were subjected to a vacuum test for leakage. The delicate exhalation 
 valve was carefully examined for defects whiclT would be liable to 
 cause leakage. Fabric for the facepieee 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 facepieee 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 main- 
 tained; the fabric was led through the rolls and wherever there was 
 
 V. Ind. Eng. Chem., 11, 185 (1919). 
 
DEVELOPMENT OF THE GAS MASK 221 
 
 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 y^ in. and to locate the stitches in some cases 
 as closely as '/« 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 assem- 
 bly 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 effi- 
 ciently 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 follow- 
 ing operation may be cited: 
 
222 CHEMICAL WARFARE 
 
 "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 des'gned trucks which pre- 
 vented injury in transit, and were delivered to the Finishing Depart- 
 ment. 
 
 "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 con- 
 veyors 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 s'des 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 wafor. 
 
DEVELOPMENT OF THE GAS MASK 
 
 223 
 
 "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. 
 
 THE ULTIMATE 
 
 \^hy Not Nou) f 
 
 Fig. 59. 
 
 m 
 
 "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 
 very detail to discover any defect that might have escaped previous 
 
224 CHEMICAL WARFARE 
 
 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. U 
 
 "As a check on the quality on the final inspectors' work a rein- ^ 
 spection 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 res- 
 pirator 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 
 
DEVELOPMENT OF THE GAS MASK 
 
 225 
 
 Division, developed two distinct types of Tissot masjis. 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 out- 
 side only and is for the purpose of strengthening and protect- 
 ing the rubber which is of very high grade. The facepiece is 
 died out as a single flat piece from the stockinet which is fur- 
 nished in long rolls. The die is of such shape that when the 
 facepiece is sewed there is but one seam, and that between 
 
226 CHEMICAL WARFARE 
 
 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 eye- 
 pieces. 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 21^X31/^ inches at the back of the head. This pad makes 
 (the harness much more comfortable. 
 
 The rubberized stockinet is reinforced on the inner or rub- 
 'ber 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 
 I and the other about two inches from the edge. This is for the 
 ipurpose of helping press the cloth against the temples, thereby 
 I adding to the gas-tightness for those heads that have a ten- 
 dency 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 
 
DEVELOPMENT OF THE GAS MASK 
 
 227 
 
 the angle tube inlet is a butterfly baffle of rubber, so arranged 
 that the incoming air is thrown upward and over the eyepieces, 
 
 Fig. 62. — 1919 Model American Mask. 
 
 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. 
 
228 CHEMICAL WARFARE 
 
 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 % 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 in- 
 creased 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 Vie 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 circu- 
 lates 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 
 
DEVELOPMENT OF THE GAS MASK 
 
 229 
 
 outer tin cap protecting the inlet valves has two openings on 
 each side but none at the ends of the canister. 
 
 The carrier is a simple canvas case nearly rectangular, about 
 one foot wide and 15 inches in length. The width is just suf- 
 
 t 
 
 Fig. 63 — 1919 Model American Mask after Adjustment. 
 
 ficient 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 
 
230 CHEMICAL WARFARE 
 
 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 liio 
 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 ^ slightly tapered metal 
 cylinder, 9 cm. in diameter at the bottom. The most satis- 
 factory fllling 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 pro- 
 tection 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 • 5II2O to 1.5 parts pumice, and the whole is covered 
 
DEVELOPMENT OF THE GAS MASK 
 
 231 
 
 vvith 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. 
 
 FiGr64. — Early Type Navy Mask. Contains nose clip 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 moisiure 
 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 
 
232 
 
 CHEMICAL WARFARE 
 
 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 eye- 
 pieces. 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. 
 
 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 
 
 -Valve 
 
 Fig. 65. — Ammonia Canister — "Kupramite." 
 
 ammonia and for 21^ 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 
 
DEVELOPMENT OF THE GAS MASK 
 
 233 
 
 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. 
 
 Under these conditions, it became evident that the wear- 
 ing of the mask caused a very great reduction in the military 
 efficiency of the soldier. The reasons for this reduction in 
 
 Fig. 66. — Ammonia Mask, Showing Relative Size of Canister. 
 
 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. 
 
234 CHEMICAL WARFARE 
 
 (2) Abnormal conditions of vision, due to poor optical quali- 
 ties 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 
 
DEVELOPMENT OF THE GAS MASK 235 
 
 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 in- 
 creasing the dead air space as follows : 
 
 1. Interpretation from the physiological standpoint: 
 (a) A larger minute-volume of air is required when breath- 
 ing 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. Any- 
 thing 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. 
 
 (6) 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 ten- 
 dency 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 
 issues to be raised to a higher level than normal, and thus again 
 ere is some reserve power wasted. 
 
 2. Interpretation from the standpoint of the canister. 
 
 tThe life of the canister depends on the volume of the gas- 
 den air passed through it. The dead space increases the 
 inute-volume of air passed through the canister and, therefore, 
 
 ^_tis! 
 
236 CHEMICAL WARFARE 
 
 Physiologically, the reason for the harmful effects of breath- 
 ing 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 im- 
 portant 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^ 
 
 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 canis- 
 ter, 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 concen- 
 tration 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 pro- 
 longed leakage of smaller amounts would have serious results in 
 the case of some gasas. The activity of the present gas mask 
 charcoal is shown by the fact that it will reduce a concentration 
 
 * The basis of this chapter is the series of articles by Lamb and 
 co-workers which appeared in the J. Ind. Eng. Chem. for 1919. 
 
 237 
 
238 CHEMICAL WARFARE 
 
 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 pre- 
 viously 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 
 difificulty of having separate canisters for various gases is con- 
 sidered, as well as the difficulty in rapidly and accurately identi- 
 fying 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 char- 
 coal. 
 
 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 ulti- 
 mate 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 dis- 
 integrate 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. 
 
ABSORBENTS 239 
 
 Charcoal 
 
 The fact that charcoal would condense in its pores or adsorb 
 certain gases, holding them firmly, had been known for a long 
 time.^ 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. 
 
 f Raw Materials^ 
 
 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 ful- 
 filled 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 pro- 
 duce carbon as efficient, volume for volume, as that of the cocoa- 
 nut shell and other hard nuts. 
 
 * Bancroft (J. Phys. Chem. 24, 127, 201, 342 (1920)) gives a compre- 
 hensive review of * * Charcoal before the War. ' ' 
 
 ^Part of this section is quoted from '^Armies of Industry," by Crowell 
 an^ Wilson, Yale Univ. Press. 
 
240 CHEMICAL WARFARE 
 
 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 im- 
 portation 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 
 
ABSORBENTS 241 
 
 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. 
 
 I 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 
 role. As a pure hypothesis, at first, Chancy assumed that an 
 active charcoal could only be secured by removing the hydro- 
 carbon which he assumed to be present after carbonization. 
 Being difficultly volatile, these hydrocarbons prevent the adsorp- 
 tion 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 
 
242 CHEMICAL WARFARE 
 
 come off at 300°, and when cooled, condensed to crystalline 
 plates. 
 
 This experiment not only proved the existence of com- 
 ponents 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 tempera- 
 tures, 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. 
 
 "The second step, that is, the removal of the absorbed hydrocarbons 
 from the primary carbon, is a much more difficult matter. Prolonged 
 
ABSORBENTS 
 
 243 
 
 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 
 
 Combustion, 
 Gaa Exit 
 
 Charcoal 
 Intake Valve 
 
 Superheated Steam 
 Exit to Furnace 
 
 IP 
 
 ^^vhich has yielded the best results, is to remove the adsorbed hydro- 
 ^Htrbons by various processes of combined oxidation and distillation, 
 ^■^hereby the hydrocarbons of high boiling points are broken down into 
 ^^Bore volatile substances and removed at lower temperatures, or under 
 ^Hpnditions less likely to result in subsequent deposition of inactive 
 ^Htrbon. Thin layers of charcoal and rapid gas currents are used so 
 ^^■at contact between the volatilized hydrocarbons and the hot active 
 
 |G. 67. Dorsey Reactor for Activating Cocoanut Charcoal with Steam. 
 
244 CHEMICAL WARFARE 
 
 hydrocarbons at high temperature, with consequent deposition of in- 
 active carbon, is largely avoided. 
 
 "While the removal of the hydrocarbons by oxidation and dis- 
 tillation 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 enl'arges, 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 con- 
 sumed. 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 
 
 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 
 
ABSORBENTS 
 
 245 
 
 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. 
 
 I 
 
 Fig. 68. — Section of Raw Cocoanut Shell. Magnified 146^ diameters. 
 
 The air, steam and also carbon dioxide-steam activation 
 *ocesses have all been employed on a large scale by the 
 lemical Warfare Service for the manufacture of gas mask 
 irbon. 
 
 "The above considerations are illustrated fairly well by the photo- 
 micro^aphs 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 
 
246 
 
 CHEMICAL WARFARE 
 
 Fig. 69. — Section of Carbonized Cocoanut Charcoal. 
 Magnified 146^ Diameters. 
 
 Fig. 70. — Two- Minute Charcoal not Activated. 
 Magnified 732 Diameters. 
 
ABSORBENTS 
 
 2A1 
 
 '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 apiJear black, while the charcoal itself appears 
 white. It is clear from this i^hotograph that much of the original 
 grosser structure of the slicU persists in the carbonized products. Figs. 
 70 and 71 are more highly magnified photographs of a carbonized 
 cliarcoal before and after activation, respectively. As before, all the 
 
 Fig. 71. — 31-Minute Steam Activated Charcoal. 
 Magnified 732 Diameters. 
 
 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 
 ructure on which the adsorption really depends. These photographs, 
 jrefore, show how the porosity is increased by activation." 
 
 The great demand for charcoal, and the need for activating 
 ler than cocoanut charcoal led to the development of the 
 
248 
 
 CHEMICAL WARFARE 
 
 Dressier tunnel kiln, which seemed to offer many advantages 
 over the Dorsey type of treater. 
 
 "The Dressier tunnel kiln is a type used in general ceramic work. 
 The furnace consists essentially of a brick kiln about 190 ft. long, 
 12 ft. broad, and 9 ft. high, Hned with fire brick. Charcoal is loaded 
 
 Fire Brick 
 
 Development Division 
 
 CHEMICAL WARFARE SERVICE U.S.A. 
 
 Defense Department 
 
 NELA PARK, CLEVELAND 
 
 SECTIONAL VIEW OF 
 DRESSIER TUNNEL KILN 
 
 Drawn by Fiivate C. R. Gai-thwait 
 October IGth '18 
 
 Fig. 72. — Sectional View of Dressier Tunnel Kiln, Adapted to Activation of 
 
 Charcoal. 
 
 in shallow, refractory trays in small tram cars, about 120 trays to 
 the car. The cars enter the kiln through a double door and the 
 charcoal remains in the hot zone at a temjaerature of about 850° C. 
 for about 4 hrs., depending upon the nature of the material charged. 
 Water is atomized into this kiln, and a positive pressure maintained 
 in order to exclude entrance of air. The kiln is gas-fired and the 
 charcoal is activated by the steam in the presence of the combustion 
 gases. 
 
ABSORBENTS 249 
 
 "Under such treatment the charcoal is given a high degree of 
 activation without the usual accompanying high losses. Seemingly the 
 oxidizing medium used, together with the operating conditions, produce 
 a deep penetration of tlie charcoal particles without increasing the 
 extensive surface combustion experienced in the steam activators. The 
 capacity of such a type furnace is limited only by the size of the 
 installation. 
 
 "The advantages of this type furnace may be tabulated as follows: 
 
 1 — High quality of product. 
 
 2 — Small weight and volume losses. 
 
 3 — Large capacity per unit. 
 
 4 — Minimum initial cost and maintenance of installation. 
 
 5 — Simplicity and cheapness of operation. 
 
 6 — Adaptability to activation of all carbon materials. 
 
 7 — Availability of furnaces of this general type already constructed." 
 
 Substitutes for Nut Charcoal 
 
 The first experiments were made with a special anthracite 
 coal (non-laminated and having conchoidal fracture). This 
 had a life of 560 minutes as against 360 minutes for air treated 
 cocoanut charcoal and 800-900 minutes for steam treated char- 
 coal. 
 
 When the Gas Defense Service tried to activate anthracite 
 on a large scale in vertical gas retorts at Derby, Connecticut, 
 the attempt was a failure. They carbonized at 900° and then 
 turned on the steam with the result that the steam-treated 
 coal had a slightly greater density than the untreated, which 
 was wrong, and had a shiny appearance in parts with 
 roughened deposits in other parts. When the hydrocarbons 
 are decomposed at high temperatures, the resulting carbon 
 ii? somewhat graphitic, is itself inactive, is not readily oxidized, 
 and impairs or prevents the activation of the normal carbon 
 upon which it is deposited. This discovery made it possible 
 to treat anthracite successfully. The conditions must be such 
 as to minimize high-temperature cracking, to carry off or 
 oxidize the hydrocarbons as fast as formed, and especially 
 to prevent the gases from cooler portions of the treater coming 
 
250 CHEMICAL WARFARE 
 
 in contact with carbon at a much higher temperature. With 
 these facts in mind, a plant was built at Springfield which 
 produced 10 tons a day of 150-300 minute charcoal from raw 
 anthracite. This was one-third of the total production at that 
 time and was mixed with the nut charcoal made at Astoria, 
 thereby preventing an absolute shortage of canister-filling 
 material in October, 1918. 
 
 It was next shown that the cocoanut charcoal fines result- 
 ing from grinding and screening losses and amounting to 50 
 per cent of the product, could be very finely ground, mixed 
 with a binder, and baked like ordinary carbon products. By 
 avoiding gas-treating in the bake, the resulting charcoal is 
 nearly as good as that from the original shell. A recovery 
 plant for treating the cocoanut fines was built at Astoria. The 
 product was called ''Coalite." 
 
 The great advantage of cocoanut shell as a source of char- 
 coal is that it is very dense and consequently it is possible 
 to convert it into a mass having a large number of fine pores, 
 whereas a less dense wood, like cedar, will necessarily give 
 more larger pores, which are of relatively little value. The 
 cocoanut charcoal is also pretty resistant to oxidation which 
 seems to make selective oxidation a more simple matter. By 
 briquetting different woods, it is possible to make charcoal 
 from them which is nearly equal to that from cocoanut shell. 
 
 By heating lamp black with sulfur and briquetting, it 
 was possible to make a charcoal having approximately the 
 same service time as cocoanut charcoal. A charcoal was made 
 by emulsifying carbon black with soft pitch, which gave the 
 equivalent of 400 minutes against chloropicrin before it had 
 been steam-treated. This looked so good that the plans were 
 drawn for making a thousand pounds or more of this product 
 at Washington to give it a thorough test. This was not done 
 on account of the cessation of all research work. The possible 
 advantage of this product was the more uniform distribution 
 of binder. 
 
 Instead of steam-treating anthracite coal direct, it was 
 also pulverized, mixed with a binder, and baked into rods 
 which were then ground and activated with steam. The result- 
 
ABSORBENTS 251 
 
 iiig material, which was known as Carbonite, had somewhat 
 less activity than the lamp-black mixes but was very much 
 cheaper. A plant was built to bake 40 tons a day of this 
 material, which would yield 10 tons a day of active carbon 
 after allowing for grinding losses and steam treatment. The 
 plant was guaranteed to furnish an absorbent having a life 
 of 600 minutes against chloropicrin. 
 
 German Charcoal 
 
 After the Armistice was signed, Chancy took up the ques- 
 tion of how the Germans made their charcoal. The German 
 charcoal was made from coniferous wood and was reported 
 to be as good as ours, in spite of the fact that they were 
 using inferior materials. Inside of a month Chancy had found 
 out how the German charcoal was made, had duplicated their 
 material, and had shown that it was nothing like as good as 
 our charcoal. The Germans impregnated the wood with zinc 
 chloride, carbonized at red heat, and washed out most of the 
 zinc chloride. When this zinc chloride was found in the Ger- 
 man charcoal, it was assumed that it had been added after 
 the charcoal had been made. It was therefore dissolved out 
 with hydrochloric acid, thereby improving the charcoal against 
 chloropicrin. The German charcoal was then tested as it 
 stood, including the fines, against American charcoal, 8 to 14 
 mesh. The most serious error, however, was in testing only 
 against a high concentration of chloropicrin. The German 
 charcoal contains relatively coarse pores which condense gases 
 at high concentrations very well but which do not absorb 
 gases strongly at low concentrations. The result was that 
 the German charcoal was rated as being four or five times 
 as good as it really was. 
 
 Comparison of Charcoal 
 
 The following table shows a comparison of charcoals from 
 different sources. The method of activation was identical and 
 
German Charcoal. X200. 
 
 252 
 
 Fig. 73. — Charcoal from Spruce Wood. 
 
ABSORBENTS 
 
 253 
 
 the times of treatment were those approximately giving the 
 highest service time. The results against chloropicrin, there- 
 fore, represent roughly the relative excellence of the charcoal 
 obtainable from various raw materials, using this method of 
 activation : 
 
 Comparison of Various Active Charcoals Activated in Laboratory 
 
 Base Material 
 
 Apparent 
 Density 
 
 Steam Treat- 
 ment at 900° 
 
 Accelerated 
 Chloropicrin 
 Test Results 
 
 
 Primary 
 Carbon 
 
 Activated 
 Carbon 
 
 Time 
 Min. 
 
 Weight 
 
 Loss 
 Per Cent 
 
 Weight 
 Absorbed 
 Per Cent 
 
 Service 
 Time 
 Min. 
 
 Sycamore 
 
 0.158 
 0.223 
 0.420 
 0.465 
 0.520 
 0.700 
 0.659 
 0.540 
 0.710 
 0.710 
 
 0.080 
 0.097 
 0.236 
 0.331 
 0.316 
 0.460 
 0.502 
 0.322 
 0.445 
 0.417' 
 
 18 
 
 60 
 
 60 
 
 60 
 
 120 
 
 120 
 
 120 
 
 210 
 
 120 
 
 180 
 
 53 
 88 
 44 
 44 
 71 
 70 
 48 
 68 
 60 
 75 
 
 41 
 78 
 32 
 31 
 46 
 48 
 51 
 85 
 61 
 72 
 
 7.3 
 
 Cedar. . 
 
 16.0 
 
 Mountain mahogany 
 Ironwood 
 
 16.3 
 20.8 
 
 Brazil nut 
 
 32.2 
 
 Ivory nut 
 
 47.0 
 
 Cohune nut 
 
 Babassu nut 
 
 Cocoanut 
 
 53.4 
 
 58.7 
 58.4 
 
 Cocoanut 
 
 64.4 
 
 Briquetted Materials 
 
 Sawdust 
 
 Carbon black . . 
 Bituminous coal 
 Anthracite coal. 
 
 0.542 
 
 0.365 
 
 120 
 
 66 
 
 53 
 
 0.769 
 
 0.444 
 
 240 
 
 64.3 
 
 53 
 
 0.789 
 
 0.430 
 
 165 
 
 61 
 
 58.3 
 
 0.830 
 
 0.371 
 
 480 
 
 81 
 
 53 
 
 40.0 
 50.5 
 46.8 
 40.7 
 
 "In conclusion, it will be of interest to compare the charcoals manu- 
 factured and used by the principal belligerent nations, both with one 
 another and with the above-mentioned laboratory preparations. Data 
 on these charcoals are given in the following table: 
 
254 
 
 CHEMICAL WARFARE 
 
 Comparison of Typical Production Charcoals of the Principal 
 Belligerent Nations 
 
 Country 
 
 Date 
 
 United States 
 
 Nov. 1917 
 
 United States 
 
 June, 1918 
 
 United States 
 
 Nov. 1918 
 
 England 
 
 1917 
 
 England 
 
 Aug. 1918 
 
 France 
 
 1917-18 
 
 Germany 
 
 Early 
 
 Germany 
 
 June, 1917 
 
 Germany 
 
 June, 1918 
 
 Raw Material 
 
 Cocoauut 
 
 Mixed nuts, etc. . 
 
 Cocoanut 
 
 Wood 
 
 Peach stones, etc. 
 
 Wood 
 
 Wood 
 
 Wood 
 
 Wood 
 
 Appar- 
 ent 
 Den- 
 sity 
 
 0.60 
 0.58 
 0.51 
 0.27 
 0.54 
 0.23 
 ? 
 
 0.25 
 0.24 
 
 Service 
 Time 
 Corr. 
 
 to 8-14 
 Mesh 
 
 10 
 
 18 
 
 34 
 
 6 
 
 16 
 
 2 
 
 3 
 
 33 
 
 42 
 
 Remarks 
 
 Air activated 
 Steam activated 
 Steam activated 
 Long distillation 
 
 Chemical and 
 steam treatment 
 
 Chemical and 
 steam treatment 
 
 Chemical and 
 steam treatment 
 
 "It is at once evident that the service time of most of these 
 charcoals is very much less than was obtained with the laboratory 
 samples. However, in the emergency production of this material on 
 a large scale, quantity and speed were far more important than the 
 absolute excellence of the product. It will be noted, for instance, 
 that the cocoanut charcoal manufactured by the United States, even in 
 November, 1918, was still very much inferior to the laboratory samples 
 made from the same raw material. This was not because a very active 
 charcoal could not be produced on a large scale, for even in May, 
 1918, the possibility of manufacturing a 50-min. charcoal on a large 
 scale had been conclusively demonstrated, but this activation would 
 have required two or three times as much raw material and five times 
 as much apparatus as was then available, due to the much longer time 
 of heating, and the greater losses of carbon occasioned thereby. 
 
 "It should furthermore be pointed out that the increase in the 
 chloropicrin service time of charcoal from 18 to 50 min. does not 
 represent anything like a proportionate increase in its value under 
 field service conditions. This is partly due to the fact that the increased 
 absorption on the high concentration tests is in reality due to con- 
 densation in the capillaries, which, as has been pointed out, is not of 
 much real value. More important than this, however, is the fact 
 
absorbent;s 
 
 255 
 
 that most of the important gases used in warfare are not held by 
 adsorption only, but by combined adsorption and chemical reaction, 
 for which purpose an 18-min. charcoal is, in general, almost as good 
 as a 50-min. charcoal." 
 
 Typical Absorptive Values of Different Charcoals Against Various 
 
 Gases 
 
 
 Charcoal 
 
 Nation 
 
 a 
 
 c 
 o 
 O 
 
 o 
 
 II 
 
 Service Time, Minutes 
 Standard Conditions 
 
 No. 
 
 a 
 3 
 
 1 
 
 'H 
 
 .s 
 
 2 
 
 < 
 
 If 
 
 IS 
 
 .2-g 
 
 •i 
 
 1 
 
 Poor cocoanut. . . . 
 
 U. S. A. 
 
 
 
 10 
 
 120 
 
 175 
 
 20 
 
 18 
 
 55 
 
 50 
 
 270 
 
 2 
 
 Medium cocoanut 
 
 U. S. A. 
 
 
 
 30 
 
 350 
 
 260 
 
 25 
 
 25 
 
 65 
 
 65 
 
 370 
 
 3 
 
 Good cocoanut. . . 
 
 U. S. A. 
 
 
 
 60 
 
 620 
 
 310 
 
 27 
 
 30 
 
 75 
 
 70 
 
 420 
 
 4 
 
 Same as No. 2 but 
 
 
 
 
 
 
 
 
 
 
 
 
 wet 
 
 U. S. A. 
 
 12 
 
 18 
 
 320 
 
 330 
 
 35 
 
 16 
 
 35 
 
 95 
 
 
 5 
 
 No. 2 impregnated 
 
 U. S. A. 
 
 
 
 35 
 
 400 
 
 700 
 
 70 
 
 400 
 
 70 
 
 190 
 
 510 
 
 '6 
 
 Wood 
 
 French 
 British 
 British 
 
 
 
 
 
 2.5 
 
 6 
 
 16 
 
 25 
 
 70 
 
 190 
 
 75 
 
 90 
 
 135 
 
 9 
 18 
 30 
 
 
 
 4 
 
 25 
 
 1 
 
 5 
 
 65 
 
 20 
 30 
 60 
 
 
 7 
 
 Wood 
 
 
 8 
 
 Peach stone 
 
 
 9 
 
 Treated wood 
 
 German 
 
 
 
 42 
 
 230 
 
 105 
 
 20 
 
 20 
 
 22 
 
 25 
 
 
 10 
 
 No. 9 impregnated 
 
 German 
 
 30 
 
 9 
 
 90 
 
 320 
 
 16 
 
 1 
 
 110 
 
 120 
 
 
 Standard Conditions of Tests 
 
 Mesh of absorbent 8-14 
 
 Depth of absorbent layer 10 cm. 
 
 Rate of flow per sq. cm. per min 500 cc. 
 
 Concentration of toxic gas. 0.1 per cent 
 
 Relative humidity 50 per cent 
 
 Temperature 20° 
 
 Results expressed in minutes to the 99 per cent efficiency points. 
 
 Results corrected to uniform concentrations and size of particles. 
 
 Soda Lime 
 
 Charcoal is not a satisfactory all round absorbent because 
 it has too little capacity for certain highly volatile acid gases, 
 such as phosgene and hydrocyanic acid, and because oxidizing 
 
256 CHEMICAL WARFARE 
 
 agents are needed for certain gases. To overcome these defi- 
 ciencies the use of an alkali oxidizing agent in combination 
 with the charcoal has been found advisable. The material 
 actually used for this purpose has been granules of soda lime 
 containing sodium permanganate. Its principal function may 
 be said to be to act as a reservoir of large capacity for the 
 permanent fixation of the more volatile acid and oxidizable 
 gases. 
 
 The development of a satisfactory soda lime was a difficult 
 problem. The principal requirements follow : Its activity is not 
 of vital importance, as the charcoal is able to take up gas with 
 extreme rapidity and then later give it off more slowly to the 
 soda lime. Ahsoiytive capacity is of the greatest importance, 
 since the soda lime is relied upon to hold in chemical combination 
 a very large amount of toxic gas. Both chemical stability and 
 mechanical strength are difficult to attain. The latter had never 
 been solved until the war made some solution absolutely 
 imperative. 
 
 Composition of Regular Army Soda-Lime 
 
 The exact composition of the army soda-lime has under- 
 gone considerable modification from time to time as it has 
 been found desirable to change the raw materials or the method 
 of manufacture. A rough average formula which will serve 
 to bring out the interrelation between the different consti- 
 tuents is as follows: 
 
 CoMrosiTiON OF Wet Mix 
 
 Per Cent 
 
 Hydrated lime 45 
 
 Cement 14 
 
 Kieselguhr 6 
 
 Sodium hydroxide 1 
 
 Water 33 (approx.) 
 
 After Drying 
 
 Moisture content 8 (approx.) 
 
 After Spraying 
 
 Moisture content 13 (approx.) 
 
 Sodium permanganate content 3 (approx.) 
 
ABSORBENTS 257 
 
 Within limits, the method of manufacture is more important 
 than the composition or other variables, and has been the 
 subject of a great deal of research work even on apparently 
 minor details. The process finally adopted consists essentially 
 in making a plastic mass of lime, cement, kieselguhr, caustic 
 soda, and water, spreading in slabs on wire-bottomed trays, 
 allowing to set for 2 or 3 days under carefully controlled 
 conditions, drying, grinding, and screening to 8-14 mesh, and 
 finally spraying witli a strong solution of sodium permanganate 
 with a specially designed spray nozzle. The spraying process 
 h a recent development, most of the soda-lime having been 
 made by putting the sodium permanganate into the original 
 wet mix. Many difficulties had to be overcome in developing 
 the spraying process, but it eventually gave a better final 
 product, and resulted in a large saving of permanganate whicli 
 was formerly lest during drying, in fines, etc. 
 
 Function of Different Components 
 
 Lime. The hydrated lime furnishes the backbone of the 
 absorptive properties of the soda lime. It constitutes over 
 50 per cent of the finished dry granule and is re sponsible in 
 a chemical sense for practically all the gas absorption. 
 
 Cement. Cement furnishes a degree of hardness adequate 
 to witlistand service conditions. It interferes somewhat with 
 the absortive properties of the soda lime and it is an open 
 question whether the gain in hardness produced by its use 
 is valuable enough to compensate for the decreased absorption 
 which results. 
 
 Kieselguhr. The loss in absorptive capacity due to the 
 presence of cement is in part counterbalanced by the simul- 
 taneous introduction of a relatively small weight though con- 
 siderable bulk, of kieselguhr. In some cases, there seems to 
 be a reaction between the lime and the kieselguhr, which 
 results in some increase in hardness. 
 
 Sodium Hydroxide. Sodium hydroxide has two primary 
 functions in the soda lime granule. In the first place, a small 
 amount serves to give the granule considerable more activity. 
 The second function is to maintain roughly the proper moisture 
 
258 CHEMICAL WARFARE 
 
 content. This water content (roughly 13-14 per cent after 
 spraying) is very important, in order that the maximum gas 
 absorption may be secured. 
 
 Sodium Permang'anate. The function of the. sodium per- 
 manganate is to oxidize certain gases, such as arsine,^ and to 
 act as an assurance of protection against possible new gases. 
 The purity of the sodium permanganate solution used was 
 found to be one of the most important factors in making stable 
 soda lime. It was, therefore, necessary to work out special 
 methods for its manufacture. Two such methods were devel- 
 oped, and successfully put into operation. 
 
 Careful selection of other material is also necessary, and 
 this phase of the work contributed greatly to the final develop- 
 ment of the form of soda lime. 
 
 ^ Which, however, was never used on the battlefield. 
 
CHAPTER XIV 
 
 TESTING ABSORBENTS AND GAS MASKS 
 
 One of the first necessities in the development of absorbents 
 and gas masks was a method of testing them and comparing 
 their deficiencies. While the ultimate test of the value of 
 an absorbent, canister or facepiece is, of course, the actual 
 man test of the complete mask, the time consumed in these 
 tests is so great that more rapid tests were devised for the 
 control of these factors and the man test used as a .check of 
 the purely mechanical methods. 
 
 Testing op Absorbents ^ 
 
 Absorbents should be tested for moisture, hardness, uni- 
 formity of sample and efficiency against various gases. 
 
 Moisture is simply determined by drying for two hours at 
 150°. The loss in weight is called moisture. 
 
 The liardness or resistance to abrasion is determined by shak- 
 ing a 50-gTam sample with steel ball bearings for 30 minutes 
 on a Ro-tap shaking machine. The material is then screened 
 and the hardness number is determined by multiplying the 
 weight of absorbent remaining on the screen by two. 
 
 The efficiency of an absorbent against various gases depends 
 upon a variety of factors. Because of this, it is necessary 
 to select standard conditions for the test. These were chosen 
 as follows: 
 
 The absorbent under test is filled into a sample tube of 
 specified diameter (2 cm.) to a depth of 10 cm. by the standard 
 method for filling tubes, and a standard concentration (usually 
 1,000 or 10,000 p.p.m. by volume) of the gas in air of definite 
 (50 per cent) humidity is passed through the absorbent at 
 
 *Sec Fieldner and others, J. Ind. Eng. Chem., 11, 519 (1919). 
 
 259 
 
260 CHEMICAL WARFARE 
 
 a rate of 500 cc. per sq. cm. per min. The concentration of 
 the entering gas is determined by analysis. The length of time 
 is noted from the instant the gas-air mixture is started through 
 the absorbent to the time the gas or some toxic or irritating 
 reaction product of the gas begins to come through the 
 absorbent, as determined by some qualitative test. Quantita- 
 tive samples of the outflowing gas are then taken at known 
 intervals and from the amount of gas found in the sample 
 the per cent efficiency of the absorbent at the corresponding 
 time is calculated. 
 Per cent efficiency = 
 
 p.p.m. entering gas — p.p.m. effluent gas 
 
 p.p.m. entering gas 
 
 xioo. 
 
 These efficiencies are plotted against the minutes elapsed from 
 the beginning of the test to the middle of the sampling period 
 corresponding to that efficiency point. A smooth curve is 
 drawn through these points and the efficiency of the absorbent 
 is reported as so many minutes to the 100, 99, 95, 90, 80, etc., 
 per cent efficiency points. 
 
 The apparatus used in carrying out this test is shown in 
 Fig. 74. Descriptive details may be found in the article by 
 Fieldner in TJie Journal of Industrial and Engineering Chem- 
 istry for June, 1919. With modifications for high and low 
 boiling materials, the apparatus is adapted to such a variety 
 of gases as chlorine, phosgene, carbon dioxide, sulfur dioxide, 
 hydrocyanic acid, benzyl bromide, chloropicrin, superpalite, 
 etc. 
 
 As the quality of the charcoal increased, the so-called 
 standard test required so long a period that an accelerated 
 test was devised. In this the rate was increased to 1,000 cc. 
 per minute, the relative humidity of the gas-air mixture was 
 decreased to zero, and the concentration was about 7,000 p.p.m. 
 The rate is obtained by using a tube with an internal diameter 
 of 1.41 cm. instead of 2.0 cm. 
 
 Canisters 
 
 After an absorbent has been developed to a given point, 
 and is considered of sufficient value to be used in a canister, 
 
TESTING ABSORBENTS AND GAS MASKS 
 
 261 
 
 the materials are assembled as described in Chapter XII. 
 While the final test is the actual use of the canister, machine 
 tests have been devised which give valuable information 
 regarding the value of the absorbent in the canister and the 
 lethod of filling. 
 
 Ficj. 74. — Standard Two-tube Apparatus for Testing Absorbents, Showing 
 Arrangement for Gases Stored in Cylinders. ; < i , . 
 
 The first test must be that for leakage. The canister must 
 show no signs of leaking when submitted to an air pressure 
 of 15 inches of mercury (about lialf of the normal atmospheric 
 pressure). 
 
 The second factor tested is the resistance to air flow. This 
 is determined at a flow of 85 liters per minute and should 
 
262 
 
 CHEMICAL WARFARE 
 
 not exceed 3 inches. The latest canister design has a much 
 lower resistance (from 2 to 2i/^ inches). 
 
 The third test is the efficiency of the canister against various 
 gases. For routine work, phosgene, chloropicrin and hydro- 
 cyanic acid are used against the standard mixture of charcoal 
 and soda lime: Chloropicrin is usually used against straight 
 charcoal fillings, while phosgene and hydrocyanic acid are used 
 against soda lime. 
 
 Water Batb 
 
 Mixing Cbamber 
 
 Fig. 75. — Apparatus for Testing Canisters Against Chloropicrin. 
 
 Different types of apparatus are required for these gases. 
 They are very complicated, as may be seen from the sketch 
 in Fig. 75, and yet a man very quickly learns the procedure 
 necessary to carry out a test of this kind. The gas is passed 
 through the canister under given conditions, until at the end 
 of the apparatus a test paper or solution indicates that the 
 gas is no longer absorbed but is passing through unchanged. 
 This point is called the ''break point," and the time required 
 to reach this point is known as the life of the canister. This 
 time is also the time to 100 per cent efficiency. Other points, 
 
r 
 
 TESTING ABSORBENTS AND GAD MASKS 263 
 
 m 
 
 I 
 
 such as 99, 95, 90 and 80 per cent efficiency are determined. 
 These are used in comparing canisters. 
 
 The canister tests were of two general classes: continuous 
 and intermittent. In the first the air gas mixture was drawn 
 through continuously until the break point was reached. The 
 results obtained in this way, however, did not give the time 
 measure of the value of a canister in actual use. The inter- 
 mittent test differs only in that the flow of air-gas mixture 
 is intermittent, corresponding to regular breathing. Special 
 valves were adapted to this work. 
 
 Canisters must also be tested as to the protection they 
 offer against smoke. These methods are discussed in Chapter 
 XVIII. 
 
 . Man Tests 
 
 The final test of the canister is always carried out by means 
 of the so-called ^'man test." Special man-test laboratories 
 were built at Washington, Philadelphia and Long Island. 
 These are so constructed that, if necessary, a man may enter 
 the chamber containing the gas and thus test the efficiency of 
 the completed gas mask. In most cases, however, the canister 
 is placed inside or outside the gas chamber and the men 
 breathe through the canister, detecting the break point by 
 throat and lung irritation. 
 
 The following brief description of the man test laboratory 
 at the American University will give a good idea of the plan 
 and procedure.^ 
 
 The man test laboratory is a one-story building, 56 ft. 
 in length and 25 ft. in width. The main part is occupied by 
 three gas chambers, laboratory tables, and various devices for 
 putting up and controlling gas concentrations in the chambers. 
 
 small part at one end is used as an office and storeroom. 
 
 Good ventilation is of great importance in a laboratory 
 of this nature. This is secured by means of a 6 ft. fan con- 
 nected to suitable ducts. The fan is mounted on a heavy frame- 
 v/ork outside and at one end of the building. The fan is driven 
 
 * Taken from Fieldner 's article mentioned above. 
 
264 
 
 CHEMICAL WARFARE 
 
 at a speed of about 250 r.p.m. by a 10 h.p. motor. The main 
 duct is 33 in. square, extending to all parts of the building. 
 A connection is also made to a small hood used when making 
 chemical analyses. 
 
 The gases, fumes, etc., drawn out by the fan, are forced 
 up and out of a stack 30 in. in diameter, extending upward 
 55 ft. above the ground level. 
 
 The main features of each of the three gas chambers are 
 identical. Auxiliary pieces of apparatus are used with each 
 
 Fig. 76. — Man Test Laboratory, American University. 
 
 chamber, the type of apparatus being determined by the char- 
 acteristics of the gas employed. 
 
 Each chamber is 10 ft. long, 8 ft. wide and 8^/2 ft. high, 
 having, therefore, a capacity of 680 cu. ft. or 19,257 liters. The 
 floor is concrete, and the walls and ceiling are constructed on 
 a framework of 2 X 4 in. scantling, finished on the outside 
 with wainscoting and on the inside with two layers of Upson 
 board (laid with the joints lapped) covered with a % in. layer 
 of special cement plaster laid upon expanded metal lath. The 
 interior finish is completed by two coats of acid-proof white 
 
TESTING ABSORBENTS AND GAS MASKS 
 
 265 
 
 paint. The single entrance to the chamber is from outside 
 the laboratory, and is closed by two doors, with a 36 X 40 in. 
 lock between them. These doors are solid, of 3-ply construc- 
 tion, 21/2 in. thick, with refrigerator handles, which may be 
 operated from either inside or outside the chamber. The door 
 jambs are lined with ^/^^ in. heavy rubber tubing to secure a 
 tight seal. 
 
 At the end of the chamber opposite the doors, a pane of 
 Vi in. wire plate glass, 36 X 48 in., is set into the wall, and 
 
 FRONT VIEW 
 
 With Standard Nuvy Canister 
 
 and Adapter in Place 
 
 SIDE VIEW 
 With Standard U.S 
 Canigter in Place 
 
 Fig. 77. — Details of Canister Holder. 
 
 additional illumination may be secured by 2 licadlights, 12 in. 
 square, set into the ceiling of the chamber and of the air-lock, 
 respectively, and provided with 200 watt Mazda lamps and 
 Holophane reflectors. Openings into the chamber, five in 
 number, are spaced across this end beneath the window and 
 9 in. above the table top. 
 
 Fans are installed for keeping the concentration uniform. 
 
 Various devices have been installed for attaching the 
 canister to be tested (Fig. 77). This arrangement allows 
 the canister to be changed at will without any necessity for 
 disturbing the concentration of gas by 'entering the chamber. 
 
266 CHEMICAL WARFARE 
 
 Arrangements for removing the gas from the chamber con- 
 sist of a small ^'bleeder" which allows a continuous escape 
 of small amounts and a large blower for rapidly exhausting 
 the entire contents of the chamber. 
 
 Other general features of the equipment deal with the 
 determination of the physical condition surrounding the tests, 
 often a matter of considerable importance. The temperature 
 of the gas inside the chamber is easily ascertained by means 
 of a thermometer suspended inside the window in such a posi- 
 tion as to be read from the outside. The relative humidity 
 of the mixture of air and gas in the chamber is determined 
 by means of a somewhat modified Regnault dew point apparatus 
 mounted on the built-in table. 
 
 Pressure Drop and Leak Detecting Apparatus 
 
 Another piece of apparatus consists of a combined pressure 
 drop machine and leak tester (Fig. 78) for measuring the resist- 
 ance of canisters and testing them for faulty construction. This is 
 mounted on a small table, with the motor and air pump installed 
 on a shelf underneath. The resistance, or pressure drop, of 
 canisters is measured by the flow meter A and the water manom- 
 eter B. Air is drawn through the canister and the flow meter 
 A at the rate of 85 liters per min., the flow being adjusted by the 
 needle valve. The pressure drop across the canister is read on 
 the water manometer B, one end of which is connected to the 
 suction line, the other open to the air. The reading is generally 
 made in inches, correction being made for the resistance of the 
 connecting hose and the apparatus itself. 
 
 Canisters are tested for leaks by the apparatus shown at B 
 in Fig. 78. The canister is clamped down tightly by wing nuts 
 against a piece of heavy i/4-in. sheet rubber large enough to 
 cover completely the bottom of the canister and prevent any 
 inflow of air through the valve. Suction is then applied, and a 
 leak is indicated by a steady flow of air bubbles through the 
 liquid in the gas-washing cylinder E. A second gas-washing 
 cylinder, empty, is inserted in the line between E and the 
 canister as a trap for any liquid drawn back when the suction 
 
TESTING ABSORBENTS AND GAS MASKS 
 
 267 
 
 is shut off. If a leak is shown, it can be located by applying air 
 pressure to the canister and then immersing it in water. 
 
 Fig. 78. — Apparatus for Determining Pressure Drop and for Detecting Leaks 
 
 in Canisters. 
 
 Methods of Conducting Tests 
 
 Three general methods of conducting man tests are followed : 
 (1) Canisters are placed in the brackets outside the chamber 
 or fastened to the wall tubes within the chamber. The subjects 
 of the test remain outside the chamber, and the facepieces of the 
 masks are connected directly to the canisters, in the first case, 
 and to the wall tubes connecting with the canisters, in the second 
 case. The concentration is established and the time noted. Then 
 the men put on the masks and breathe until they can detect the 
 gas coming through the canisters. Reading matter is provided 
 for the men during the test period. When gas is detected, the 
 time is again noted and the time required for the gas to penetrate 
 the canister is reported as the ' ' time to break down " or " service 
 time" of the canister. Ten canisters are tested at one time, and 
 the average of the results for the 10 canisters is taken for that 
 type of canister. Much less accurate results are obtained when 
 
268 CHEMICAL WARFARE 
 
 the final figure is based on a small number of canisters. This is 
 largely due to the various breathing rates and sensitiveness of 
 different men. 
 
 (2) The canisters are placed as in (1), but it is only neces- 
 sary to know if they will give perfect protection for a given 
 length of time. The procedure is the same as in (1), except that 
 the test is arbitrarily stopped at the end of the indicated time, 
 and the number of canisters and the service times of the same 
 noted. 
 
 (3) When the canisters are of such a type that they cannot 
 be properly tested as in (1), or when it is desired to test the 
 penetrability of the facepiece, the men wear the complete mask 
 and enter the chamber. They remain until gas penetrates the 
 canister or the facepiece, as the case may be, or until it is deter- 
 mined that the desired degree of protection is afforded. The 
 service time is computed as in (1). 
 
 (4) Maximum-breathing-rate tests are made either by men in 
 the chamber or by the men outside, in which they do vigorous 
 work on a bicycle ergometer. In this test the average man will 
 run his breathing rate up to 60 or 70 liters per min. 
 
 The concentration of the gas is followed throughout the test 
 by aspirating samples and analyzing them. 
 
 Type of Masks Used. In the future the 1919 model will be 
 used for all tests. In general, during the War, the following 
 procedure held, although variations occurred in special cases : 
 
 When men entered a gas chamber, the full facepiece was, of 
 course, required. The type of facepiece was determined by the 
 nature of the gas. If the gas was most easily detected by odor 
 or eye irritation, a modified Tissot mask was used. If it was 
 most easily detected by throat irritation, a mouth-breathing 
 mask was employed. 
 
 When men were outside the chamber, the choice was made in 
 the same manner, except in the case of detection of the gas by 
 throat irritation. In this case the mouthpiece was attached to 
 two or three lengths of breathing tubes and a separate noseclip 
 was used. The facepiece was not needed and the men were 
 much more comfortable without it. 
 
 Disinfection of Masks. Mouthpieces are disinfected after 
 use by first holding them under a stream of running water and 
 
TESTING ABSORBENTS AND GAS MASKS 269 
 
 brushing out thoroughly with a test-tube brush ; then the latter is 
 dipped into a 2 per cent solution of lysol, and the inner parts of 
 the mouthpiece are brushed out well ; finally the mouthpiece and 
 exhaling valve are dipped bodily into the lysol solution and 
 allowed to dry without rinsing. Tissot masks are wiped out with 
 a cloth moistened in alcohol, followed by another cloth moistened 
 in 2 per cent lysol solution. The flexible tubes are given periodic 
 rinsings whh 95 per cent alcohol. 
 
 Applicability of Man Tests. Man tests are applicable to 
 all gases which can be detected by the subject of the test before 
 he breathes a dangerous amount. 
 
 The man test laboratory described above provides facil- 
 ities for obtaining information concerning the efficiency of 
 canisters, facepieces, etc., within very short periods of time, 
 without waiting for the construction of special apparatus 
 required for machine tests. To get satisfactory results from 
 machine tests, a delicate qualitative chemical test for the gas is 
 essential. Man tests can be made when such a qualitative test 
 is not known. Further, man tests can be made with higher con- 
 centrations of some gases than is practicable with machines. 
 Evolution of excessive amounts of moisture when high concentra- 
 tions of some gases are used causes much more trouble with 
 machine tests than with man tetsts. 
 
 On the other hand, man tests are adversely affected by the 
 varying sensitiveness and lung capacities of the men, and the 
 humidity of the air-gas mixture is not subject to as exact control 
 as is the case with machine tests. 
 
 Field Tests 
 
 It will be observed that all of the above tests are concerned 
 only with the efficiency of the absorbent and its packing in the 
 canister. No attempt was made to determine the comfort and 
 general **feel" of the mask. For this purpose field tests were 
 devised, covering periods from two to five hours. The first test 
 was a five-hour continuous wearing test. It was assumed that 
 any mask which could be worn for five hours without developing 
 any mark-ed features of discomfort could, if the occasion de- 
 
270 
 
 CHEMICAL WARFARE 
 
 manded it, be worn for a much longer period of time, 
 test follows: 
 
 A typical 
 
 Gas- 
 
 8 : 00 to 8 : 30 Instruction and adjustment of gas mask. 
 
 chamber tests 
 
 8 : 30 to 9 : 30 Games involving mental and physical activity 
 
 9 : 30 to 1 1 : 30 Cross-country hike with suitable periods of rest 
 
 1 1 : 30 to 1 2 : 00 Tests of vision 
 
 12 : 00 to 12 : 30 Games to test mental condition of subjects 
 
 12 : 30 to 1 : 00 Gas-chamber fit test 
 
 Fig. 79. — Hemispherical Vision Chart. 
 
 Vision was tested by means of a hemispherical chart (Fig. 
 79). This chart was 6 ft. in diameter and was constructed of 
 heavy paper laid over a wire frame. A hinged head rest was pro- 
 vided for holding the subject's head firmly in position with the 
 
TESTING ABSORBENTS AND GAS MASKS 271 
 
 center directly between the eyes. The subject wearing the mask took 
 up his position, and with one eye closed at a time, indicated how 
 far along the meridian of longitude he could see with the other 
 eye. The observer sketched in the limit of vision by outlining the 
 perimeter of the roughly circular field allowed by each eyepiece. 
 The intersection of the two fields gave the extent of binocular 
 vision possible with the mask. 
 
 Various other tests were also used, in order that the extent 
 and nature of the vision could be accurately determined. 
 
 Aside from the problems of comfort, protection, vision and 
 other important features of gas mask efficiency, the question 
 arose as to whether certain designs of masks or canisters were 
 mechanically able to withstand the rough treatment they were 
 certain to receive in actual field service. A test was, therefore, 
 developed to simulate such service as transportation of masks 
 from base depots to the front, carrying of supplies and munitions 
 by men wearing masks in the ''alert" position, exposure to rain 
 and mud, hasty adjustment of masks during gas alarms and 
 typical mistreatment of masks by the soldiers. 
 
 All these tests were of great value in the development of a 
 good gas mask. 
 
CHAPTER XV 
 OTHER DEFENSIVE MEASURES 
 
 Protective Clothing 
 
 Protective clothing was an additional feature of the general 
 program of protection. As far as factory protection is con- 
 cerned, the use of protective garments was more or less of a 
 temporary expedient and they were abandoned as fast as auto- 
 matic machinery and standard practice made their use less 
 necessary. It is likewise a question regarding their value at the 
 front. It is very certain that the garments developed needed to 
 be made lighter and more comfortable to be of much value to 
 the fighting unit. 
 
 The first development of protective clothing was along the 
 lines of factory protection. The large number of casualties in 
 connection with the manufacture of mustard gas made it impera- 
 tive that the workmen be protected not only from splashes of the 
 liquid mustard gas, but also from its vapors. The first suit de- 
 veloped provided protection to the entire body. The ordinary 
 clothing materials and even rubberized fabrics offered little 
 protection but it was found that certain oilcloths were practically 
 impermeable to mustard gas. The suit was a single garment, 
 buttoning in the back, with no openings in the front, no pockets 
 and with tie-strings at wrists and ankles. The head was pro- 
 tected by means of an aluminium helmet, supported by means 
 of a head band resting on the head like a cap and slung from 
 the inside of the helmet; this permitted slight head motions 
 independent of the helmet. In order to provide cooling and 
 ventilating and pure air breathing, the suit was inflated by 
 pumping a considerable volume of air into the suit through a 
 flexible hose long enough to permit considerable freedom of 
 movement. 
 
 272 
 
I 
 
 OTHER DEFENSIVE MEASURES 
 
 273 
 
 This suit had the very great disadvantage of limiting the 
 range of motion to the length of the hose. Because of this, a 
 Tissot type mask was used in place of the helmet and hose con- 
 nections. The hood was made of the same special oilcloth as the 
 suit, enveloped the head and neck and extended a short distance 
 down the back and over the chest. The canister was slung on 
 the left hip by an oilcloth harness and was kept from swinging 
 by an oilcloth belt around the waist. The canister was much 
 
 Fig. 80. — Impervious Overall Suit for Mustard Gas. 
 
 larger than the standard box respirator, had a much longer life 
 with lower resistance and weighed about 3.5 lbs. 
 
 Another type of impervious overall suit was developed which 
 protected against mustard gas for over 100 minutes. The 
 material was a cotton sheeting which was impregnated with 
 linseed oil containing a suitable non-drying material, which was 
 thoroughly oxidized in the fabric. These suits proved to be very 
 uncomfortable, especially in warm weather, because they entirely 
 prevented the escape of perspiration from the body. 
 
274 CHEMICAL WARFARE 
 
 Semi-permeable suits were then prepared, in which the 
 cotton sheeting was impregnated or coated with a solution of 
 gelatin and glycerine. The fabric was then *' tanned '* to render 
 the gelatin insoluble in water. Such a suit is valuable for factory 
 wear, but the impregnating material is easily leached out and 
 the suit is therefore not recommended for field service. 
 
 This was built with an inside layer of dry cloth together with 
 an outside layer of treated cloth to afford the necessary chemical 
 protection against mustard gas. Work of fabrication consisted 
 in treating the cloth with simplexene, cutting the suits to design 
 and size, and sewing them together. 
 
 Treatment consisted in passing the fabric through a dye 
 machine, then through the wringer rolls where the excess oil 
 was expressed. The inner layer of dry cloth was found neces- 
 sary, since the cloth was cut as soon as treated. Simplexene does 
 not attain the maximum degree of *' tackiness '* for two or three 
 days, owing to the presence in the oil of a small amount of 
 volatile spirits. However, by allowing the cloth to air for 48 
 hours before cutting, the inner lining could probably be dis- 
 pensed with. 
 
 The fighting suits were distributed among various detach- 
 ments using mustard gas in field tests, and in other places where 
 protection against vapor was needed and where field conditions 
 were approximated. The tests showed that the suit gave satis- 
 factory protection for considerable periods against mustard gas 
 vapors. No other suit, equal both in porosity and protection, has 
 yet been submitted, although samples furnishing better pro- 
 tection with much higher resistance have been examined. The 
 protection of the simplexene suit is about 30 minutes against 
 saturated gas. A large number of these suits were made and 
 taken abroad for field tests at the front. 
 
 Protective Gloves 
 
 Protective gloves have been made with a variety of impreg- 
 nating agents. The one which was selected for large scale pro- 
 duction was impregnated with a solution of cellulose nitrate 
 because of the availability of materials and the protection offered 
 by the finished product. The material is impregnated after 
 
OTHER DEFENSIVE MEASURES 
 
 275 
 
 being made up. The one finger type of glove is used. The gloves 
 are placed on wooden forms and dipped into the impregnating 
 solution. After draining a few minutes, the gloves are turned 
 upside down on racks and run through a drying oven. Finally 
 they are removed from the forms and conditioned by drying at 
 a moderate temperature for several hours. After being properly 
 cured they are fitted with two straps on the gauntlet of each 
 glove. They should offer protection to chloropicrin (standard 
 
 I 
 
 Fig. 81. — Coated Gloves for Protection against Mustard Gas. 
 
 ethod of test) for 30 minutes. When subjected to rough work 
 they will last from one to two weeks. 
 
 Protective Ointments 
 
 The extensive use of mustard gas on the field caused the men 
 to be exposed to low concentrations of the vapors for extended 
 periods of time. Since it did not seem feasible to furnish the 
 men with special fighting suits, which would protect them against 
 these vapors, it was desirable to provide protection in the form 
 of an ointment which could be applied to the body. In order to 
 be satisfactory an ointment should have the following properties : 
 
276 CHEMICAL WARFARE 
 
 {a) It should protect against saturated mustard gas during 
 the longest possible exposure. 
 
 (6) Its protective action should last as long as possible after 
 the application of the ointment. It was felt that the ointment 
 should give protection for 24 hours after it is applied, even if 
 the body is perspiring freely. 
 
 (c) The material should not be easily rubbed off under the 
 clothing. 
 
 (d) It should be non-irritating to the membranes of the body. 
 
 (e) There should be no likelihood of toxic after-effects on 
 long use. 
 
 (/) It should be of a good consistency under a fairly wide 
 temperature range and give a good coating at the temperature of 
 the body. 
 
 (g) Its method of manufacture should be simple and rapid, 
 and the raw materials required should be abundant. 
 
 (h) The cost should not be excessive. 
 
 An extensive study of this question was made both in the 
 laboratories and on the field. At first it was believed that suc- 
 cessful results could be obtained by the use of such ointments. 
 Careful investigation showed, however, that while these oint- 
 ments really did protect against rather high concentrations of 
 vapor for short times of exposure, they were probably not so 
 valuable when used against low concentrations over an 
 extended period of time. It was further demonstrated that 
 the protection furnished by a coating of linseed oil is prac- 
 tically equal to the best ointment which has been developed. 
 About 150 ointments were prepared and tested. These 
 consisted of two parts or components, the metallic soap or 
 other solid material and the oil or liquid part which bound and 
 held the solid. The latter is called the base. The best base is 
 lanolin, containing 30 per cent of water. A solution of wax in 
 olive oil was next best. Of the metallic soaps the oleates and 
 linoleates are better than the stearates. A satisfactory ointment 
 has the following composition : 
 
 Zinc oxide 40 
 
 Linseed oil (raw) •. 20 
 
 Lard 20 
 
 Lanolin 20 
 
OTHER DEFENSIVE MEASURES 277 
 
 A modification of this formula is : 
 
 Zinc oxide 45 
 
 Linseed oil 30 
 
 Lard 10 
 
 Lanolin 15 
 
 The physical properties of this -ointment are very good. It 
 forms a smooth, even coating on the skin, sticks well enough not 
 to rub off easily on the clothing and yet is not sticky. Its con- 
 sistency is such that it can be readily pressed from an ointment 
 tube. A. E. F. reports indicate that -sag paste (zinc stearate 
 and vegetable oil) is as satisfactory as any of the preparations 
 tried. 
 
 The great difficulties of such preparation from a field point 
 of view are : Extra weight to be carried by the soldiers, necessity 
 for keeping in tight boxes or tubes, thereby adding to the diffi- 
 culty of carrying, and finally, the difficulty encountered when 
 applying it properly to the body in the field, where gas con- 
 taminated hands may cause harm. 
 
 The paste was too late a development for thorough field trial. 
 It was used just enough to cause severe partisan controversies 
 between its advocates and those opposed to it. Unquestionably, 
 it proved of decided value in preventing mustard gas burns 
 when properly applied. There are many authentic cases where 
 men alongside each other were similarly gassed except as to 
 burns. The difference in burns arose from the use or non-use 
 of the paste, and in some cases of poor application. Fries is 
 of the opinion that had the war lasted another year the use of 
 pastes would have become universal unless some thoroughly 
 successful substance for impregnating the uniform or under- 
 clothing had been developed. This is likewise his belief for the 
 future. 
 
 Protection of Animals 
 
 Horse Mask. The need of protection for animals (horses 
 and dogs), although not as great as in the case of men, was of 
 sufficient importance so that masks and boots were developed for 
 the horse and a mask for. the dog. 
 
 m 
 
278 
 
 CHEMICAL WARFARE 
 
 The German horse mask was the first produced. It was of 
 the nose bag type, enveloping the mouth and nose of the animal. 
 It was fitted with a complicated drawstring and with snap hooks 
 fastening it to the harness. The interior contains a plate of stiff 
 material to prevent the collapse of the bag. The mask itself was 
 apparently not impregnated, but was used wet or with a filling 
 of wet straw or rags to act as the absorbent. 
 
 The French had two types of horse masks impregnated with 
 a glycerine-nickel hydroxide mixture. One type had a closed 
 bottom, while in the othe^*, the bottom was open. 
 
 The British horse mask has a two-layer flannelette bag, with 
 a canvas mouth pad and elastic drawstring. It was impregnated 
 
 BACK VIEW SIDE VIEW BOX FOR RESPIRATOR 
 
 Fig. 82. — German Respirator for Horses. 
 
 with a mixture of phenol, formaldehyde, ammonia, canister soda 
 and glycerine. 
 
 The first type of American horse mask was modelled after 
 the British and was impregnated with the Komplexene mixture 
 (hexamethylenetetramine, glycerine, nickel sulfate mixture). 
 This mask had too high a resistance and caused complete exhaus- 
 tion in running horses. The second mask was made of a large 
 number of layers of very open cheesecloth. It consists of two 
 bags, impregnated with different mixtures (Komplexene and 
 Simplexene). Horses can run two miles with this mask without 
 showing evidences of exhaustion. 
 
 Dewey gives the following method of manufacture: 
 
 The chemical employed consisted of a mixture of hexa- 
 
OTHER DEFENSIVE MEASURES 
 
 279 
 
 methylenetetramine (to give protection against phosgene), 
 nickel sulfate (to protect against the possible use of hydrocyanic 
 acid), sodium carbonate and glycerine. This solution was mixed 
 in a heavy steam jacketed mixing kettle with heavy geared 
 stirrers. The mixture was conducted by pipes to the impreg- 
 nating apparatus which consisted of a rotary laundry washing 
 machine. The masks were treated in this machine for 15 
 minutes, and then placed in a power operated wringer and the 
 
 Fig. 83. — Horse Mask — American Type. 
 
 solution driven off to a given weight. Following this operation, 
 they were suspended on wire supports and conducted through a 
 hot air drying machine and dried to a definite weight. 378,000 
 horse masks were produced at the rate of 5,000 per day. 
 
 Theoretically, horse masks and horse boots are very valuable, 
 — practically, they did very little actual good in the field, not 
 that they would not protect or that animals would not wear them. 
 The trouble was with the riders and drivers. Gas attacks, 
 coming usually at night, made adjustment of horse masks diffi- 
 cult at best, while in the confusion of bursting shell and smoke, 
 
280 CHEMICAL WARFARE 
 
 the drivers absolutely forgot the horse masks or after putting on 
 their own masks feared to try putting masks on the animals. 
 This last was natural as most animals fight the adjustment of 
 the mask and in so doing there is great risk that the man^s mask 
 may be torn off and the man gassed. In the future, such masks 
 will have even more importance than in the past, for the present 
 methods of manufacture of mustard gas coupled with its all- 
 round effectiveness will cause a use of it ten-fold greater than at 
 any time in the World War. In such cases, operations will neces- 
 sarily be frequently carried on over large areas thoroughly 
 poisoned with mustard gas. Here the animals will be masked 
 and booted before entering the gassed area, and remain so until 
 they leave it. In the torn and broken ground around the front 
 line there will always be need for animal transportation, — 
 wagon, cart and horse — as in such places it is far better in nearly 
 all cases than motor transport. 
 
 Dog Mask. The use of dogs in messenger service and in 
 Red Cross work, in which gassed areas must be passed, led to the 
 designing of a mask to give the animals suitable protection. The 
 same materials and method of impregnation were used as in the 
 horse mask. With eight layers of cheesecloth, adequate protec- 
 tion against mustard gas was secured with practically no pres- 
 sure drop. 
 
 The eyepieces were made of thin sheets of cellulose acetate 
 bound around the edge with adhesive tape and sewed directly 
 over openings cut through the mask fabric. The ear pockets 
 were made round and full enough to fit pointed or lop-eared 
 animals. The mask is continued to form a wide neck band 
 which may be drawn up by two adjustable straps. It is made 
 sufficiently full to allow a free movement of the dog's jaws and 
 yet tight enough around the neck to avoid the possibility of being 
 pawed off. The dog apparently soon became accustomed to 
 wearing the mask. 
 
 Horse Boots. The increasing amount of mustard gas used 
 on the Western front made it seem necessary to develop some 
 form of protection for the horse's hoof and fore-leg. It has 
 been found that mustard gas vapors attack the fleshy portion of 
 the leg, especially around the coronary band and causes inflam- 
 mation of the frog of the foot. The problem was solved by 
 
OTHER DEFENSIVE MEASURES 
 
 281 
 
 devising a special lioof pad and a boot. The pad was made of 
 sheet iron imbedded in a hoof protector (composition rubber) to 
 which the shoe is applied. The shoe just overlaps the metal plate 
 
 Fig. 84. — Impervious Boots and Pads to Protect Horses' Legs and Hoofs 
 against Mustard Gas. 
 
 on the inside and provides a solid metal surface for the bottom 
 of the foot. Such a pad not only offers protection against gas 
 but against shell splinters, barbed wire, etc., and would be useful 
 at ail times on the front. 
 
282 
 
 CHEMICAL WARFARE 
 
 The boot was made of satin, treated so as to be impervious 
 to mustard gas. It covers all of the foot except the bottom and 
 extends to just below the knee. The boot is held in contact with 
 the hoof by a sewed cloth strap, which passes around the bottom 
 
 Fig. 85. — Protective Gas Outfit — Gas Mask, Gas Suit, Gloves, Boots, Horse 
 Mask, Horse Boots, Horse Pads. 
 
 of the hoof and is held in position by projections extending from 
 the spur or toe clip. Special care is taken to insure a perfect 
 joint at the rear of the boot since the small cavity in the back of 
 the hoof is one of the most sensitive parts. The boot is wrapped 
 about one and a half times around the leg and is clipped with five 
 loops through which passes a %-inch strap. 
 
OTHER DEFENSIVE MEASURES 283 
 
 Dugout Blankets. Dugout protection is intended to pre- 
 vent entrance of any gases, lethal, lachrymatory or irritant, into 
 the enclosed space. This has been most efficiently accomplished 
 by means of curtains hung upon wooden frames and fitting 
 closely against all edges of the opening to be closed. These cur- 
 tains have usually been of heavy material and have generally 
 been spoken of as dugout blankets. Since they were designed to 
 exclude all toxic gases, they had to be devised upon general 
 mechanical principles rather than upon principles of chemical 
 action with specific gases. Permeability to air has not been 
 considered a necessity, it being held that sufficient ventilation is 
 secured by means of the air entering through the soil. For large 
 dugouts and extended use large air filters were designed to draw 
 pure air into the dugout with a fan. 
 
 The qualities aimed at, to which both fabric and treatment 
 should contribute, are the following: 
 
 (o) Impermeability to gas. 
 
 (&) Flexibility, especially at low temperatures. 
 
 (c) Non-inflammability. 
 
 (d) Freedom from stickiness and from tendency to lose material by 
 drainage under action of gravity. 
 
 (e) Mechanical strength. 
 
 (/) Simplicity of manufacture and treatment. 
 (g) Low cost. 
 
 Army blankets, both those for men and those for horses, 
 proved suitable materials for curtains, but the scarcity of wool 
 made it desirable to select an all cotton fabric. 
 
 A large number of oils were studied as impregnating agents. 
 The most satisfactory mixture consisted of 85 per cent of a heavy 
 steam refined cylinder oil and 15 per cent of linseed oil. This is 
 taken up to the extent of about 300 per cent increase in weight 
 of the blanket during impregnation. It becomes oxidized to some 
 extent upon the surface of the blanket, which becomes less oily 
 than the soft, central core. The finished blanket possessed the 
 following properties: It resists penetration of 400-600 p.p.m. 
 of chloropicrin for 8 hours (dugout test) and mustard gas for 
 100-400 minutes (machine test). It is sufficiently flexible after 
 standing for 2 hours at 18° F. to unroll of its own weight, and 
 
284 CHEMICAL WARFARE 
 
 may be unrolled by applying a slight force at 6° F. ; it is not 
 ignited by lighted matches and shows but little loss by drainage. 
 Two types of machines were designed for impregnation, one 
 for use on large scale behind the line, and a field apparatus for 
 use at the front. 
 
I 
 
 CHAPTER XVI 
 \ SCREENING SMOKES 
 
 The intelligent use of screening smokes in modern infantry 
 tactics offers innumerable advantages through concealment and 
 deception. It confers upon daylight operations many of the 
 advantages which were gained by conducting operations at night 
 with few of the disadvantages of the latter. 
 
 Smoke screens have been frequently used by the Navy and 
 by Merchantmen ; a common method of escape was to shut off the 
 air from the fire with consequent incomplete combustion of the 
 fuel, thus causing a cloud of dense black smoke. This is often 
 mentioned in the blockade runners of the days in the Civil War, 
 where wood, high in pitch and rosin, was freely introduced into 
 the furnaces, in order that they might escape under cover of this 
 smoke. 
 
 Early in the present war it was found that black smoke had 
 a low obscuring power, showed frequent rents or holes and were 
 difficult to standardize. Their production also caused a con- 
 siderable loss in the speed of the vessel. They therefore fell into 
 disuse except for emergency purposes and today the standard 
 smoke for screening purposes of all kinds is, without exception, 
 white.^ /" 
 
 \>£boperties of Smoke Cloud 
 
 The properties most desired in a screening smoke, apart from 
 low cost, are: (a) Maximum screening power, which refers to the 
 question of density, i.e., a relatively thin layer must completely 
 obscure any object behind it, and (6) Stability, which implies, 
 among other things, a low rate of settling or dissipation. There 
 is little reason to doubt that, within limits, the smaller the 
 
 ' While it is a well known fact that black smoke is not as efficient 
 as white smoke for screening purposes, the reason for this fact is not clear. 
 
 28;" 
 
286 CHEMICAL WARFARE 
 
 particles of a smoke cloud, the more completely will the smoke 
 possess these qualities. The screening power of a smoke cloud 
 depends very largely upon the scattering of the light coming 
 through it, and by analogy with those peculiar solutions which 
 we call colloidal, we should expect the scattering to increase as 
 the degree of subdivision increases, within limits. The rate of 
 settling is unquestionably an inverse function of the size of the 
 particles. The chief aim, therefore, in smoke production is to 
 attain as high a degree of subdivision as possible. Methods may 
 be classified as good or bad, in so far as they satisfy or fail to 
 satisfy this criterion. 
 
 Raw Materials for Smoke Clouds 
 
 It is obvious that only gases or substances capable of being 
 brought into the vapor state or into a very fine state of sub- 
 division can be used for producing smoke clouds. The reaction 
 product, of which the smoke particles consist, should preferably 
 be: 
 
 {a) Solid. Otherwise the particles will tend to grow in size 
 by condensation of the liquid particles present in the cloud. 
 
 (&) Non-volatile. If volatile, the particles will disappear by 
 evaporation as the cloud is diluted by air currents. Larger par- 
 ticles will also form at th.e expense of the smaller ones. 
 
 (c) Non-deliquescent. If the particles are deliquescent, they 
 will tend to grow by condensation of water vapor upon them. 
 
 (d) Stable towards the usual components of the atmosphere, 
 especially moisture. 
 
 "While it might seem that it would be difficult to fulfill these 
 conditions, there are several chemical compounds which have 
 been successfully used as smoke producers. This does not mean 
 that they fulfill all the conditions, but they represent a compro- 
 mise between the various requirements. 
 
 \ Phosphorus. One of the earliest materials to be used in 
 smoke clouds was phosphorus. This is prepared on a commercial 
 scale by heating phosphate rock (which contains calcium phos- 
 phate) with sand and coke in an electric furnace. Phosphorus 
 occurs in two forms, white and red. White phospliorus, which 
 is formed when the vapor of the substance is quickly cooled, is, 
 
I 
 
 SCREENING^ SMOKES 287 
 
 in the pure state, almost colorless, melts at 44° C, boils at 287° 
 C, is readily soluble in various solvents, and is luminous in the 
 air, at the same time emitting fumes (the oxidation product, 
 phosphorus pentoxide). On gentle warming in the air, it takes 
 fire and burns with a brightly luminous flame. Red phosphorus 
 is obtained by heating white phosphorus out of contact with the 
 air, to a temperature of 250° to 300° C. Red crusts then sep- 
 arate out from the colorless liquid phosphorus, and almost the 
 entire amount is gradually converted into a red, solid mass. If 
 this is freed by suitable solvents from the small amounts of un- 
 changed white phosphorus, a dark red powder is obtained, which 
 remains unchanged for a long time in the air, does not appre- 
 ciably dissolve in the solvents for white phosphorus, does not 
 become luminous, and can be heated to a fairly high temperature 
 without igniting. Further, red phosphorus is not poisonous, 
 while white phosphorus is highly so. 
 
 Either form burns to phosphorus pentoxide, which is con- 
 verted by the moisture of the air to phosphoric acid, 
 
 4P+5 02 = 2P205 
 2 P2O5+6 H20 = 4 H3PO4 
 
 Since one pound of phosphorus takes up 1.33 pounds of 
 oxygen and 0.9 pound of water, it is not surprising that 
 phosphorus is one of the best smoke producers per pound of 
 material. Comparison of the value of the two forms for shell 
 purposes have invariably pointed to the superiority of the 
 white variety. 
 
 In addition to its use as a smoke producer, it is used in 
 incendiary shell and in tracer bullets. For incendiary purposes 
 a mixture of red and white phosphorus is superior. 
 
 Chlorosulfonic Acid. Chlorosulf onic acid, CISO2OH, was 
 first employed by the Germans to produce white clouds, both 
 on land and on sea. For this purpose, they sprayed or dropped 
 it onto quicklime, the reaction between it and the lime furnish- 
 ing the heat necessary for volatilization, though in this way 
 about 30 per cent of the acid is wasted. 
 
 Chlorosulfonic acid is obtained from sulfur trioxide and 
 hydrogen chloride, which combine when gently heated : 
 
 S03+HC1 = C1S020H 
 
288 
 
 CHEMICAL WARFARE 
 
SCREENING SMOKES 289 
 
 On a commercial scale, hydrogen chloride is passed into 
 20 per cent oleum, until saturation is reached. This is heated 
 in a nitric acid still, when the chlorosulfonic acid distills over 
 between 150°-160° C. With 30 per c6nt oleum, the conversion 
 factor is about 42 per cent. The residue in the still is about 
 98 per cent sulfuric acid. 
 
 . It forms a colorless liquid, boiling at 152° C, and having 
 a density of 1.7. 
 
 Chlorosulfonic acid fumes in the air, because reaction with 
 water forms sulfuric acid and hydrochloric acid. 
 
 CISO2OH + H2O = H2SO4 + HCl 
 
 This material was not used by the United States since 
 oleum was found superior. 
 
 Oleum. Oleum is a solution of 20 to 30 per cent sulfur 
 irioxide (SO3) in concentrated sulfuric acid. It has been used 
 by the Germans to produce clouds on land and sea, by its 
 contact with quicklime, and by the Americans for screening 
 tanks and aeroplanes. Sulfur trioxide has been found to be 
 superior as a shell filling. It is believed that the smoke 
 producing power of oleum is due solely to its sulfur trioxide 
 content, the sulfuric acid itself acting only as a solvent. The 
 rather high freezing point of the oleum containing high per- 
 centages of sulfur trioxide is a disadvantage. 
 
 Sulfur Trioxide. Sulfur trioxide, SO3, is a colorless mobile 
 liquid, which boils at 46° C. and solidifies to a transparent 
 ice-like mass, melting at 15° C. It is prepared by passing 
 a mixture of sulfur dioxide and oxygen over finely divided 
 platinum or other catalysts at a temperature between 400 and 
 450° C. Sulfur trioxide can only be used as a filler for shell 
 and bombs, and is probably the best substitute for phosphorus. 
 
 Tin Tetrachloride. Tin tetrachloride, SnCl4, is obtained 
 by the action of chlorine on metallic tin. It is a liquid, boiling 
 at 114° C, and having a density of 2.2. It fumes in the air, 
 because it hydrolyzes to stannic hydroxide : 
 
 SnCl4+4 H20 = Sn(OH)4+4 HCl 
 
 It makes a better and more irritating smoke for shell and 
 and grenades, than either silicon or titanium tetrachlorides. 
 
 i 
 
290 CHEMICAL WARFARE 
 
 Since there is practically no tin in this country, the other 
 tetrachlorides were developed as substitutes. 
 
 Silicon Tetrachlodie. Silicon tetrachloride, SiCl^, is pre- 
 pared from silicon or from impure silicon carbide by heating 
 it with chlorine in an electric furnace. The raw material 
 (silicon carbide) is a by-product in the manufacture of car- 
 borundum. It is a colorless liquid, boiling at about 58° C, and 
 fumes in moist air, owing to hydrolysis : 
 
 SiCU +4 H2O = Si(0H)4 +4 HCl 
 
 It is not very valuable in shell, though it is more effective on 
 moist, cool days than on warm, dry ones. Its greatest use 
 is found in the smoke cylinder, combined with ammonia. By 
 the action of the moisture of the air, the following reaction 
 takes place: 
 
 SiCl4+4 NH3+4 H20 = Si(OH)4+4NH4Cl 
 
 The addition of a lachrymator gives a mixture which works 
 well in hand grenades for mopping up trenches. 
 |\ Titanium Tetrachloride. Titanium tetrachloride, TiCl4; is 
 made from rutile, TiOs, by mixing with 30 per cent carbon and 
 heating in an electric furnace. A carbonitride is formed, which 
 is said to have the composition TigC^N^, but the actual com- 
 position may vary from this to the carbide TiC. This product 
 is heated to 600-650° C, and chlorine passed through, giving 
 the tetrachloride. It is a colorless, highly refractive liquid, 
 which boils at about 136° C, is stable in dry air and fumes 
 in moist air. The best smoke is produced by using 5 parts 
 of water to one of the tetrachloride, instead of the theoretical 
 4 parts [which would form Ti(0H)4]. Since it is more expen- 
 sive to manufacture and not as effective as silicon or tin 
 tetrachloride, it is used only as an emergency material. 
 
 Berger Mixture. One of the most important smoke 
 materials was the zinc-containing mixture, which was used in 
 the smoke box, the smoke candle, certain of the smoke grenades 
 and in various forms of colored smokes. The basis of this 
 was the Berger Mixture, which had the composition : 
 
SCREENING SMOKES 291 
 
 Zinc ...25 
 
 Carbon tetrachloride 50 
 
 Zinc oxide 20 
 
 Kieselguhr 5 
 
 Tliis formula produced a light gray carbon smoke, with much 
 carbon in the residue. In this mixture the zinc and carbon 
 tetrachloride react to form zinc chloride and carbon; the 
 kieselguhr keeps the mixture solid by absorbing the tetra- 
 chloride, while the zinc oxide is practically useless, as its 
 absorbing power is small. 
 
 In order to accelerate the reaction and to oxidize the 
 carbon, thereby changing the color of the smoke from gray 
 to white, an oxidizing agent was added. Sodium chlorate was 
 chosen for economic reasons. The reaction now proved to be 
 too violent, and the zinc oxide w^as replaced by ammonium 
 chloride. This cooled the smoke, retarded the rate of burning 
 and added to the density of the smoke, since the obscuring 
 power of the ammonium chloride is high. The kieselguhr was 
 replaced by precipitated magnesium carbonate, which is as 
 good an absorbent, gives a much smoother burning mixture, 
 and also adds somewhat to the density of the smoke by virtue 
 of the magnesium mechanically expelled. The mixture then 
 had the composition: 
 
 Zinc 34.6 
 
 Carbon tetrachloride 40 . 8 
 
 Sodium chlorate 9.3 
 
 Ammonium chloride 7.0 
 
 Magnesium carbonate 8.3 
 
 Size of Smoke Particles 
 
 In the problem of smoke production, the size of the particle 
 is of great importance. Being a physical quantity it can 
 easily be correlated with such physical properties as settling, 
 diffusion, coagulation, and evaporation. These factors are 
 more important in connection with toxic smokes, since there 
 the penetration factor must be considered. 
 
 Smoke appears to consist of particles of all sizes from 10~^ 
 cm., which may just be resolved by the unaided eye, to molec- 
 
292 CHEMICAL WARFARE 
 
 ular dimensions, 10"^ cm. The larger particles settle out most 
 rapidly and so do not remain long in suspension. 
 
 Measurement 
 
 Wells and Gerke have developed a form of ultra-microscope 
 which is well adapted to the measurement of the size of smoke 
 particles. The ultra-microscope is a Ioav power microscope 
 using intense dark ground illumination for viewing particles 
 which are too small to be seen by transmitted light. They 
 are rendered visible in this way, since any object, no matter 
 how small, which emits enough light to affect the retina is 
 visible, provided the background is sufficiently dark. Thus 
 stars are visible at night and dust particles are easily seen 
 in a sunbeam in a darkened room. The larger particles, viewed 
 in this way, do not appear larger but brighter. The apparent 
 size of the particles is determined by the diffraction pattern 
 and is thus dependent only on the optical system used to view 
 them. The more intense the incident light, the brighter the 
 particles appear. In the ultra-microscope described, the image 
 of an intense source, such as a concentrated filament lamp, 
 or an arc, is focused upon the particles in the microscopic 
 field, but the axis of the illuminating beam, instead of coin- 
 ciding with the axis of the microscope, as ordinarily used, is 
 perpendicular to it. The beam itself, therefore, never enters 
 the microscope at all, but passes under the objective into a 
 blackened chamber where it is absorbed. The field of the 
 microscope is made dark by placing underneath the objective 
 another ** black hole" or blackened chamber with an opening 
 just a little larger than the field.^ 
 
 The method used for measuring the velocity consisted in 
 causing the particle to describe a definite stroke many times 
 in succession in an electric field. This was accomplished by 
 reversing the direction of the field with a rotating commutator. 
 The convection due to the source of light is perpendicular 
 to this motion so that a zigzag line is obtained (see Fig. 88). 
 The amplitude of this oscillation is an accurate measure of 
 
 ^ This ultra-microscope is described in J. Am. Chem. Soc. 41, 312 (1919). 
 
SCREENING SMOKES 
 
 293 
 
 m 
 
 Fig. 87. — Ultramicroscope for Measuring Size of Smcke Particles, 
 
294 
 
 CHEMICAL WARFARE 
 
 
 
 '«■! 
 
 
 _^ 1 
 
 
 
 Fig. 88. — Measurement of Smoke Particles by Use of Ultramicroscope. 
 
I 
 
 SCREENING SMOKES 295 
 
 the distance traversed by the particle under the electric force 
 for a definite small interval of time. The speed of the rotating 
 commutator and the electric field are both susceptible of pre- 
 cise measurement, so that the size of a single particle is pre- 
 cisely determined. 
 
 When a sample of smoke is viewed in the ultra-microscope, 
 it appears like the starry heavens, except that the stars are 
 dancing violently about. At first little distinction is made 
 between the particles, as there seems to be no order in their 
 motion, but soon it becomes evident that the brighter particles 
 are more sluggish than the dim ones. This is due to the 
 greater mass of the bright particles, for they are larger. The 
 particles are all moving slowly away from the source of light 
 and eventually diffuse to the walls of the cell. 
 
 When the electric field is turned on, about one-third of the 
 particles immediately migrate, about equally in both direc- 
 tions, to the two electrodes. If the field is reversed, the direc- 
 tion of migration is reversed and if the commutator is used 
 the particles oscillate regularly. Sometimes the particles may 
 be seen to combine and become neutral, in which case oscilla- 
 tion ceases. 
 
 Concentration of Smoke 
 
 In measuring the concentration of smokes, the following 
 terms are useful: 
 
 Density. The density of a smoke is defined as the reciprocal 
 of the thickness of the smoke layer in feet necessary to obscure 
 a given filament. Thus six inches of a smoke of density 2.0 
 is required to obscure an electric light filament, whereas one 
 requiring four feet would have a density of 4. Another way 
 to show the significance of this definition is to point out that 
 if a definite weight of a stable smoke is diluted with air after 
 it is formed, the product of the volume by the density always 
 remains constant. Any marked variation in this rule may be 
 taken as evidence that the particles of smoke are undergoing 
 a change, in most cases due to evaporation. 
 
 Total Obscniring Power. The volume of smoke produced 
 per unit weight of material used is the second factor in 
 determining the value of a smoke. The product of this volume 
 
296 CHEMICAL WARFARE 
 
 per unit weight by the density of the smoke is the real measure 
 of effectiveness, and is called the total obscuring power (T. 
 0. P.) of the smoke. If the volume is expressed in cubic feet 
 per pound and the density in reciprocal feet, the unit of 
 T. 0. P. is square feet per pound. That is, it expresses the 
 square feet of a smoke wall, thick enough to completely 
 obscure a light filament behind it, which could be produced 
 from a pound of the reacting substances. The total obscuring 
 power of some typical smokes are as follows: 
 
 Phosphorus 4600 
 
 NH^CKNHs+HCl) 2500 
 
 SnCl4+NH3-f HaO 1590 
 
 Berger Mixture 1250 
 
 SnCl4+NH3 900 
 
 SO2+NH3 375 
 
 In all measurements of density, and therefore of T. 0. P., 
 the rate of burning must be considered. If a slow burning ma- 
 terial be compared with a rapid one, the former will not reach 
 its true maximum density, as a great deal of the smoke may 
 settle out during the time of burning. Comparisons of T. 0. P. 
 are significant only when made on smoke mixtures of the 
 same type and in about the same quantities. 
 
 I Measurement 
 
 Two methods of measuring the effectiveness of a smoke 
 cloud have been devised, one, the smoke box, which measures 
 the obscuring power directly by observing at what distance a 
 lamp filament is obscured by intervening smoke, the other, the 
 Tyndall meter, which measures the intensity of the scattering 
 of the light. 
 
 The earliest measurements of smoke intensity are perhaps 
 those of Ringelmann {Revue Techinquef 19, 286), who devised 
 the well known chart of that name, intended mainly for 
 measuring intensities of black smoke issuing from a chimney 
 at a distance. The first measurements for military purposes 
 are probably due to Bertrand, who made numerous compara- 
 tive studies with his "salle opacimetrique. " This was a room 
 23 X 14 X 3.6 meters, with 7 windows. Two doors, one pro- 
 
SCREENING SMOKES 
 
 :97 
 
 vided with 3 oculars 2 cm. in diameter, gave access to the 
 room. On the other door, opposite the first, were hung several 
 black signs. Six pairs of columns were spaced along the room 
 at measured distances. When a smoke is produced in the 
 room, the black paper signs first become invisible, then the 
 door itself, and finally the columns, pair by pair. They reap- 
 
 Macbeth Illuminometer / 
 
 01 \ I 
 
 Di=phram D C^Z^TZT 
 
 Fig. 89.— Tyndall Meter. 
 
 pear in the reverse order, and as a measure of relative opacity 
 Bertrand took the time elapsing between the detonation and 
 the reappearance of the farther door. 
 
 Smoke Box. The smoke box, used by the C. W. S., was 
 constructed of wood with tight joints, and had a moveable 
 brass rod running through it to which was attached a small 
 size 25-Watt Mazda lamp. Tlie density of each smoke intro- 
 
298 
 
 CHEMICAL WARFARE 
 
 duced in the box is determined by moving this lamp back 
 and forth until a point is reached when the pattern of the 
 filament can just be distinguished by the observer looking 
 in at the glass window, external light being excluded by a 
 black cloth. The thickness of the smoke layer between the 
 
 Wire CraJle held in 
 
 Paraf.'.n sealing joint 
 between tubes 
 
 l' Adhesive Tape 
 
 Spring Clamp for holding / 
 control wire past ■~-~-.^_^/ 
 
 Fig. 90.— Cottrell Precipitation Tube. 
 
 glass window and the light is recorded as the measure of the 
 smoke density. For field tests, a larger box, 6X8X8 feet 
 (288 cubic feet) was constructed. The observation light was 
 moveable in a line connecting the mid-points of opposite sides 
 of the box. To insure uniform distribution of smoke, a fan 
 
SCREENING SMOKES 299 
 
 with 18-inch blade revolved at any desired speed between 
 60 and 250 r.p.m. With this, results are obtained indicating 
 both the original density and its stability. 
 
 Tyndall Meter. The Tyndall meter was first devised for 
 studying smokes and mists. Tolman and Vliet adapted it to 
 Chemical Warfare purposes, and used it in studying the 
 properties of smokes. 
 
 The apparatus (Fig. 89) consists eventually of an electric 
 light bulb, a condensing lens giving a beam of parallel light 
 which passes through the diaphragm, and a Macbeth illuminom- 
 eter for measuring the strength of the Tyndall beam. In 
 case the material is a liquid suspension or solution, it is intro- 
 duced into a cylindrical glass tube, while smokes and mists 
 are premixed directly through the apparatus. The long closed 
 tubes are provided, respectively, for absorbing the beam after 
 it has passed through the disperse system and for giving a 
 dark background for observing the Tyndall beam. Methods 
 of standardization are given in the Journal of the American 
 Chemical Society^ 41, 299. 
 
 A third method for analyzing smokes consists in the use of an 
 electrical precipitator. This apparatus consists essentially of 
 a modified Cottrell Precipitator, with a central wire as cathode 
 surrounded by a cylindrical foil as anode (Fig. 90). The 
 smoke to be analyzed is drawn through the apparatus at a known 
 rate, and the particles of smoke precipitated on the foil by means 
 of a high voltage, direct current. The determination of concen- 
 tration is made by weighing the foil before and after precipita- 
 tion. 
 
 s^ 
 
 Apparatus for Smoke Production 
 Smoke Box 
 
 The smoke box was developed for the Navy for use when it 
 was desirable to have the smoke screen generated away from the 
 ship. (The smoke funnel, described later, was operated on board 
 ship). The float consists of an iron container (holding the 
 smoke mixture) surrounded by an iron float to support the 
 apparatus when it is thrown into the water (Fig. 91). The 
 iron container consists of a cylinder 22 inches high and 
 
300 
 
 CHEMICAL WARFARE 
 
 10 inches in diameter. One-inch holes are bored II/2 inches 
 from the top of this cylinder, from which the smoke is emitted. 
 The iron float is about 2 feet in diameter and 8 inches deep. 
 
 Fig. 91. — Navy Smoke Box. 
 
 Fig. 92. — Navy Smoke Box in Action. 
 
 This box holds appi-oximately 100 pounds of smoke mixture, and 
 is so constructed that it will float one hour. When ignited, the 
 mixture burns 9 to 9i/> minutes. The smoke produced has a 
 
SCREENING SMOKES 
 
 301 
 
 T. 0. P. of about 1900. Fig. 92 shows the Navy Smoke Box 
 in action. 
 
 Smoke Candle 
 
 Smoke candles are used for producing a cloud of smoke for 
 screening purposes in or behind the lines. They are made by 
 l)aeking about three pounds of the modified Berger Mixture in a 
 container (Fig. 93) (galvanized can 514 inches by 3% inches) 
 
 Fig. 93.— B. M. Smoke Candle. 
 
 and are lighted by means of the match head type of ignition. 
 Smoke is given off at a uniform rate for about 4 minutes, form- 
 ing a dense, fog-like cloud which hangs low (Fig. 94). This 
 smoke is absolutely harmless, and can be breathed without dis- 
 comfort. The obscuring power is high and, with a favorable 
 wind, a small number of the candles will produce a screen 
 sufficiently dense to allow operations to be carried out unseen by 
 the enemy. 
 
302 
 
 CHEMICAL WARFARE 
 
 Smoke Grenade 
 
 The smoke grenade is also designed for use in trench and 
 field warfare, where it is desired to produce a dense smoke screen. 
 It is made by packing 340 grams of the standard smoke mixture 
 in an ordinary light metal gas grenade. Around the top of the 
 grenade are vents closed by a zinc strip. The ignition is caused 
 by the standard bouchon when the grenade is thrown. The heat 
 
 Fig. 94.— Smoke Cloud from B. M. Candle. 
 
 of the reaction burns through the zinc strip and a dense cloud of 
 smoke is evolved for 45 seconds. 
 
 Stannic chloride has also been used extensively in hand 
 grenades, as it gives a very disagreeable cloud of smoke upon 
 detonation. Due to the high prices and urgent need of tin for 
 other purposes, silicon tetrachloride was substituted for tin tetra- 
 chloride towards the close of the war. A mixture of silicon 
 tetrachloride and chloropicrin was also used. This not only gives 
 a very good smoke cloud, but combines with it the toxic proper- 
 ties of the chloropicrin cloud. 
 
 The method of firing the smoke grenade is the same as that 
 of any grenade using the same type of bouchon. Usually the 
 
SCREENING SMOKES 
 
 303 
 
 grenade is grasped in the hand for throwing in such a manner 
 that the handle of the bouchon is under the fingers. The safety 
 clip is pulled out with the other hand and the grenade is thrown 
 with an overhand motion. IVhen the grenade leaves the hand, 
 the handle of the bouchon flies off, allowing the trigger to hit the 
 cap which ignites the fuse. 
 
 The white phosphorus combined hand and rifle grenade be- 
 came the standard smoke grenade by the end of the war. Stan- 
 nic chloride was used to clear out dugouts, but not as a smoke 
 producer. 
 
 \ 
 
 Stokes' Smoke Shell 
 
 The Stokes' smoke shell was perfected to furnish a means of 
 maintaining the best possible smoke screen at long ranges by 
 
 Fig. 95.— Stokes' Smoke Shell. 
 
 means of an easily portable gun. The 3-inch Stokes shell, as 
 adapted for combustion smokes, weighs about 13 pounds and 
 contains about 4 pounds of standard smoke mixture. This shell 
 
304 
 
 CHEMICAL WARFARE 
 
 is designed to produce a continuous screen over a period of 3 to 
 4 minutes. 
 
 Livens Smoke Drum 
 
 The Livens smoke drum was designed for use with the 8-inch 
 Livens projector, so as to produce a smoke screen of large 
 
 Fig. 96. — Livens Smoke Bomb. 
 
 volume and long duration at long ranges. The drum, as adapted 
 for combustion smokes, weighs 17.5 pounds empty and 49 pounds 
 loaded. The smoke-gas mixture was specially adapted for use in 
 the Livens drum. 
 
 Smoke mixtures in Livens were never used to any consider- 
 able extent in the war and it is questionable if they ever will be. 
 A Livens can usually only be fired once before resetting, hence 
 Stokes mortars are used whenever possible. 
 
SCREENING SMOKES 
 
 305 
 
 Smoke Funnel 
 
 The smoke funnel was developed for the production of a 
 white smoke cloud fi'om the stern of a vessel. The smoke pro- 
 ducing materials are liquid ammonia and silicon tetrachloride, 
 with carbon dioxide as a compressing medium. This is the most 
 satisfactory compressing medium, because: (1) The silicon 
 
 :z--:^^::^t^i^ 
 
 ■i^- -^ . 
 
 Fig. 97. — Navy Smoke Funnel. 
 
 tetrachloride is forced out at nearly constant pressure. (2) The 
 carbon dioxide is easily compressed to a liquid and can be 
 handled in this form. Further, it has a vapor pressure of 800 
 pounds at 60° F., and a cylinder can be nearly emptied without 
 loss in efficiency. (3) Carbon dioxide is sufficiently soluble in 
 silicon tetrachloride to cause the latter to effervesce and thus 
 materially aid in its evaporation on spraying. (4) Liquid 
 carbon dioxide, behaving in a manner similar to liquid ammonia, 
 affords a means for the silicon tetrachloride to ''keep pace'' with 
 the ammonia, under changes in temperature, and thus ensures a 
 more nearly neutral, and therefore the most effective, smoke. 
 The smoke funnel proper consists of an open end cylinder, 
 
306 CHEMICAL WARFARE 
 
 about 2 feet in diameter and 7 feet long, mounted in a horizontal 
 position on an angle iron frame. At one end is an 18-inch fan 
 securely fastened to the cross supports. This fan is operated 
 by hand, through gears giving a ratio of about 30 to 1. The 
 silicon tetrachloride enters the cylinder through a pipe, which 
 terminates in four spray nozzles, while the ammonia enters 
 through a single nozzle. The air forced into the funnel serves 
 to hydrolyze the silicon tetrachloride and mixes the vapors. The 
 resulting reaction evolves a dense white cloud of very large 
 volume and high obscuring power. One set of cylinders is 
 
 Fig. 98. — Navy Smoke Funnel in Operation. 
 
 capable of maintaining this cloud for over 30 minutes. Under 
 normal conditions the discharge is at the rate of 2 pounds 
 of silicon tetrachloride to 1 pound of ammonia. To stop the 
 smoke, the silicon tetrachloride is closed first, the ammonia 
 allowed to run about half a minute, and the fan is shut off last. 
 
 Smoke Knapsack n 
 
 The smoke knapsack furnishes a portable apparatus for smoke 
 production. The gross weight is about 70 pounds; when in 
 operation it gives a dense white smoke for about 15 minutes. 
 The operation may be intermittent or continuous and the quan- 
 tity of smoke is sufficient to completely hide one platoon of men 
 
SCREENING SMOKES 307 
 
 in skirmish formation with a 5-mile per hour enfilade wind. 
 The apparatus consists of two steel tanks about 26 inches in 
 height and 6 inches in diameter. From the side of each tank, 
 but near the bottom, extends a short pipe on which is placed a 
 suitable valve. A flexible armored hose connects the valve to a 
 short length of pipe which is equipped with spray nozzle. The 
 cylinders are charged with silicon tetrachloride and ammonia 
 under pressure. The valves may be operated with the left hand, 
 while the sprayer apparatus is held in the right. The release 
 buckles are within easy reach of both hands. 
 
 Shell V 
 
 While many special devices have been developed by means 
 of which the gas troops and infantry are able to set up smoke 
 clouds on short notice, the smoke shell, fired by the artillery, 
 always played an important part in this work. In the same way 
 that a large number of the poison gases were adapted to artillery 
 use, so were most of the smoke producing substances. 
 
 As a filler for smoke shell, phosphorus easily ranks first, and 
 is approached only by sulfur trioxide in very humid weather. 
 A rough approximation to the relative values of some of its rivals 
 is given in the following table: 
 
 White phosphorus 100 
 
 Sulfur trioxide 60-75 
 
 Stannic chloride 40 
 
 Titanium chloride 25-35 
 
 Arsenic chloride 10 
 
 ^P Comparison of the value of different forms of phosphorus 
 for shell purposes has invariably pointed to the superiority of 
 the white variety. Mixtures of white and red (2 to 1) have also 
 proved effective. 
 
 A complete barrage over a front of 200 yards can be estab- 
 lished in from 40 seconds to 1 minute and maintained by firing 
 a salvo followed by battery fire of 3 seconds. Four 4.5-inch how- 
 itzers could maintain an effective barrage over a front of 1000 
 yards. The influence of sunshine is very marked, as in moist- 
 cool weather one shell every 15 seconds is sufficient. 
 
308 
 
 CHEMICAL WARFARE 
 
SCREENING SMOKES 309 
 
 I 
 
 Screening Tanks 
 
 Tests have demonstrated (see Fig. 99) that successful smoke 
 screens for tanks may be produced by spraying oleum into the 
 exhaust. On a 7-ton tank of the Renault type (40 H. P.) 110 cc. 
 per minute produced a large volume of smoke, which had 
 excellent covering power, and which could be made intermittent 
 or continuous at will. 
 
 The same method may be applied to aeroplanes, and to ships. 
 It is calculated that a cylinder containing 300 pounds of 20 
 per cent oleum will maintain a smoke screen on a ship for a 
 period of 15 minutes, if oleum is used at the rate of 23.6 pounds 
 per minute. Since the cylinders may be arranged in batteries, 
 the screen may be continued for any period of time. The Tank 
 Corps rather favor phosphorus rifle grenades for producing a 
 smoke screen at a distance from the tank. 
 
 Purpose of Smoke Screen 
 
 Smoke screens may be employed with one or more of the fol- 
 lowing objects in view : 
 
 I (1) To mask known enemy observation posts and machine 
 gun nests ; to conceal the front and flanks of attacking troops, 
 concentration of guns and tanks, roads and concentration points ; 
 to blind the flashes of batteries in action and to hamper aerial 
 bservations. 
 
 (2) As a feint to draw the enemy's attention to a front on 
 hich no attack is being made, so as to hold his troops to their 
 
 trenches, or to induce him to expend ammunition needlessly and 
 to put down a barrage in the wrong place. 
 
 (3) To simulate gas and force the enemy to wear his mask. 
 Gas should occasionally be mixed with smoke, to impress upon 
 him the belief that it is never safe to remain in a smoke cloud 
 without wearing his mask. 
 
 (4) In rolling or mountainous country, to fill valleys with 
 smoke and thereby conceal the advance from all observation, in- 
 cluding aerial. 
 
 (5) To cover the construction of bridges, trenches, etc., in 
 the face of the enemy. 
 
310 CHEMICAL WARFARE 
 
 The Tactical Value op Smoke 
 
 > 
 
 The pall of smoke that hung over every battlefield of the 
 Civil War made a profound impression upon Fries when, 
 as a boy, he first read of those battles. However,, prac- 
 tically every reference made to smoke treated it as a nuisance. 
 It obscured the field of vision and interfered with troop move- 
 ments as well as with the aiming and firing of rifles and cannon, 
 though due to their short range this was not so serious as it would 
 be nowadays. Nevertheless so deeply was this interference appre- 
 ciated that the most earnest efforts were made to discover a 
 smokeless powder. This, as the world well knows, was developed 
 with great efficiency during the latter part of the nineteenth 
 century. With the development of the smokeless powders came 
 also a better understanding of the action of powder, whereby the 
 velocity of projectiles, and consequently the range and accuracy, 
 were greatly increased. This increased range and accuracy of 
 guns forced a consideration of protection, — and concealment is 
 one form of protection. 
 
 The Navy would appear to have been the first branch of 
 the American forces to realize how valuable a smoke screen 
 may be. Thus Fries, in August, 1913, had the interesting 
 experience of witnessing a week's maneuvers at the eastern 
 entrance to Long Island Sound between the Navy and the Coast 
 Artillery. During that week the Navy carried out extensive 
 experiments with smoke screens both by day and by night. The 
 smoke in all cases was generated by smothering the fires on 
 destroyers or other ships, thus causing dense clouds of black 
 smoke to be given out from the funnels. 
 
 After the World War had been in progress some time and 
 particularly about the time the United States entered it, a 
 determined search was begun for more efficient smokes and more 
 efficient smoke producers. 
 
 In the Navy, smoke screens were expected to be established 
 by small craft behind which larger vessels could maneuver for 
 position and range. These screens were also established for the 
 purpose of cutting off the view of enemy submarines or other 
 vessels, thus allowing merchant ships or even warships when 
 injured or outclassed to escape. 
 
b 
 
 SCREENING SMOKES 311 
 
 The Army was mucli slower to appreciate the value of smoke. 
 In fact, apparently no army really realized the value of a smoke 
 screen until after gas warfare became an accomplished fact. As 
 is well known, the evaporation of the large quantity of liquid 
 used in wave attacks caused a cloud of condensed moisture. This 
 is what gave rise to the designation "cloud attack.*' 
 
 English regulations for defense against gas in the early days 
 called for every man and animal to stand fast upon the approach 
 of a gas cloud and remain quiet until the cloud had passed. 
 Thus casualties were reduced to a minimum and the English 
 were fresh to receive the attack that was frequently launched 
 immediately after the cloud had passed. The Germans finally 
 thought of the plan of sending over a fake gas attack. In tTiat 
 way they simply produced a smoke cloud that looked like a gas 
 attack. Naturally the English stood fast as before. The Ger- 
 mans attacking in the fake cloud naturally caught the British 
 at" a complete disadvantage with consequent disastrous results 
 to the latter. 
 
 But that was a game at which two could play. About this 
 time the value of white phosphorus for producing a smoke screen 
 was taken up by the British and large numbers of 4-inch Stokes 
 mortar shells were filled for that purpose. All armies then 
 began to experiment with smoke-producing materials. Most of 
 these were liquid. Of them all, as has been stated before, white 
 phosphorus, a solid, proved the best. Toward the close of the 
 war these smoke screens began to be used to a considerable extent 
 for the purposes given above. No one who has engaged in target 
 practice and encountered a fog, or who has hunted ducks and 
 geese in a fog needs to be told of the difficulty of hitting an object 
 he cannot see. 
 
 The First Gas Regiment proved its worth and won everlasting 
 glory by using the Stokes' mortars of the British with their 
 phosphorus bombs for attacking machine gun nests. The white 
 phosphorus in that case had a double effect. It made a perfect 
 smoke screen, thereby making the German machine gun shots 
 simply shots in the dark, while at the same time the burning 
 phosphorus forced the gunners to abandon their guns and sur- 
 render. Thus phosphorus played and will play in the future 
 the double role of forming a defensive screen and of viciously 
 
312 CHEMICAL WARFARE 
 
 attacking enemy troops. This phosphorus, which catches fire 
 spontaneously, burns wet or dry, total immersion m water alone 
 sufficing to put it out. This means of extinguishing the flames 
 being almost totally absent on the battlefield, it can be truthfully 
 said that burning phosphorus is unquenchable. The burns are 
 severe and difficult to heal. For these reasons white phosphorus 
 will be used in enormous quantities in any future war. 
 
 All armies have begun to realize this value of smoke. In the 
 future it will be the infantryman's defense against all forms of 
 weapons and it will be used on every field of battle, by every arm 
 of the service and at all times, day or night. It is even more 
 effective in shutting out the light from searchlights, star bombs 
 and similar illuminants for use in night attacks than it is in 
 daylight. With this straight use of smoke for protection will go 
 its use along with poisonous gases. Every smoke cloud will be 
 poisonous or non-poisonous at the will of the one producing the 
 cloud, and this will be true whether it is produced from artillery 
 shell, mortar bombs, hand grenades, smoke candles or other 
 apparatus. Thus smoke and gas together will afford a field for 
 the exercise of ingenuity greater than that of all other forms of 
 warfare. The only limitation to the use of smoke and gas will 
 be the lack of vision of commanders and the ignorance of armies. 
 
 Proper recognition and aid given to chemical warfare 
 development and instruction in peace are the only methods of 
 overcoming these limitations. In this, as in all other develop- 
 ment work, the most serious obstacle comes from the man who 
 will not see, whether it be from a lack of intelligence, laziness or 
 inbred opposition to all forms of advancement. 
 
CHAPTER XVII 
 TOXIC SMOKES 
 
 ifi( 
 
 le introduction of diphenylchloroarsine as a poison gas 
 really introduced the question of toxic smokes. This material, as 
 has already been pointed out, is a solid, melting at about 30°. 
 In order to secure efficient distribution, the material was mixed 
 with a considerable amount of high explosive. When the shell 
 burst, the diphenylchloroarsine was finely divided or atomized 
 and produced a cloud of toxic particles. Since smoke particles 
 are only slightly removed by the ordinary mask, this formed a 
 very effective means of chemical warfare. 
 
 An analogous result was obtained by the use of poison gases, 
 such as chloropicrin, in a smoke cloud produced from silicon or 
 stannic chloride. Here, however, the toxic material was a real 
 gas, and so the real result attained consisted in forcing the men 
 to wear their masks in all kinds of clouds. The true toxic smoke 
 went further in that the ordinary mask offered little protection 
 and thus compelled the warring nations to develop a special 
 type of smoke filter. 
 
 These smoke clouds consist of very small particles, which may 
 be considered as a dispersed phase, distributed in the air, which 
 we may call the dispersing medium. The dispersed phase may 
 be produced by mechanical, thermal, or chemical methods. 
 
 Mechanical dispersion consists in the tearing apart of the 
 material into a fine state of subdivision. It may be called a 
 hammer and anvil action. The more powerful the mechanical 
 force, the smaller the resulting particles. This may be accom- 
 plished by the use of a high explosive, such as the Germans used 
 in the case of diphenylchloroarsine. 
 
 The production of smoke by thermal dispersion depends 
 essentially upon, the fact that when a substance of sufficiently low 
 vapor pressure is volatilized, and the vapors are passed into the 
 
 313 
 
314 CHEMICAL WARFARE 
 
 air, they re-condense on the nuclei of the air to form a smoke. 
 Vaporization from an open container, permitting the vapors to 
 pass directly to the air without being quickly carried away from 
 the surface of evaporation, produces smoke having larger par- 
 ticles, because each particle formed remains for an appreciable 
 period of time in contact with air saturated with vapor, and 
 hence grows very rapidly. 
 
 The easiest way to produce small smoke particles is to mix 
 the toxic material directly with some fuel which will produce a 
 large amount of heat and gas upon burning. When this mixture 
 is enclosed in a container having a small orifice, upon burning, 
 the toxic vapor and gas will pass through this orifice at high 
 velocity; it has been demonstrated by Lord Rayleigh that the 
 size of the particles depends upon the velocity of emission of the 
 gas from a given orifice. 
 
 The product of chemical combination may include a super- 
 saturated vapor, which condenses into small particles. 
 
 Explosive dispersion is really a combination of mecJianical 
 dispersion followed by thermal dispersion. 
 
 Penetration n\ 
 
 The fundamental idea underlying all the work on toxic 
 smokes is to obtain a smoke that has marked penetrating power. 
 Screening power is not important here. In addition to penetra- 
 tion, a smoke should be highly toxic and have a slow rate of 
 settling. 
 
 Penetration may be tested by the use of a standard filter; a 
 suitable filter for this purpose is one which does not remove the 
 smoke to such an extent that measurement of its concentration 
 becomes difficult, and one which does not become clogged quickly 
 by the smoke. A filter consisting of two pads of felt, placed side 
 by side and arranged so that the smoke first comes in contact 
 with the thinner and less dense pad has been found very satis- 
 factory. 
 
 In testing penetration, smoke is produced by dispersing one 
 gram of the toxic substance in a sheet iron box of 1000 liters 
 capacity. After 5 minutes a steady concentration is usually 
 attained and the smoke is then forced through a Tyndall meter. 
 
TOXIC SMOKES 
 
 315 
 
 I 
 
 H (see page 299) after dilution with air, where the initial con- 
 centration is determined. It then passes through the standard 
 filter, and through a second Tyndall meter, where the final con- 
 centration is measured. The difference of the two readings gives 
 the amount of smoke retained by the filter. The penetration is 
 ordinarily represented by a series of figures, which decrease 
 from a maximum value at the beginning of the test to a minimum 
 at a point where the filter permits the passage of so little smoke 
 
 Fig. 100. — Penetration Apparatus Used to Test Toxic Smokes. 
 
 that it cannot be measured. This decrease is due to decrease in 
 penetrating power and concentration of the smoke, and to in- 
 crease in filtering power of the filter as a result of plugging. 
 Usually five degrees of penetration are recognized, excellent, 
 good, fair, poor and very poor, 
 
 A portable penetration apparatus is shown in Fig. 100. In 
 using the apparatus, the smoke producing material is so placed 
 with reference to the apparatus that the sample is taken about 
 20 feet down the wind, so that the smoke is appreciably diluted 
 One man is stationed at each Tyndall meter and takes readings 
 
316 CHEMICAL WARFARE 
 
 as fast as his recorder can write them, so that the smoke density, 
 before and after the filter, can be followed very closely. 
 
 Physiological Action 
 
 In addition to a high penetrating power a smoke should also 
 possess great toxic, irritant, sternutatory, or lachrymatory 
 power. These properties are tested by exposing mice to the 
 smoke in the chamber. They are placed in the chamber at the 
 beginning of the run, and exposed for 10 minutes to the smoke 
 from 1 gram of the material. While these tests are only quali- 
 tative in character, they give a fairly goocj notion of the relative 
 value of different materials. 
 
 Quantitative Relationships 
 
 It has been found that, if the optical readings from the 
 Tyndall meter are plotted as ordinates against the time t (the 
 time elapsed after detonation) as abcissas, and that portion of 
 the curve between t=0 and ^=30 considered, the curve generally 
 descends sharply at first, from a high point representing the 
 density immediately after the production of the smoke, to a 
 point in the neighborhood of t=8, where it flattens out and 
 descends much more slowly with a slope that changes little. The 
 area under the significant portion of the curve, that is, the area 
 circumscribed by the curve from the point t^o to (q, the vertical 
 axis from this point to the origin, the horizontal axis from the 
 origin to ^30 and the line perpendicular to this axis, cutting the 
 curve at t^Q, is a rough measure of the relative values of different 
 smokes. This area is calculated as the sum of two rectangles, 
 from to to #8 and from fg to ^30- 
 
 Some results are as follows : 
 
 Area 30 
 
 Phenyl dichloroarsine 181 
 
 Triphenyldichloroarsine 178 
 
 ; Diphenylcyanoarsine 1 37 
 
 Diphenylchloroarsine 101 
 
 Cyanogen bromide 94 
 
 Methyl dichloroarsine 70 
 
 Phenylimidophosgene 69 
 
 Mustard gas 38 
 
TOXIC SMOKES 
 
 317 
 
 The curves in Fig. 101 show the way in which the readings 
 fall off with time. Each substance of course has its characteristic 
 curves. 
 
 18.0 
 
 
 
 
 17.4 
 
 
 
 
 16.8 
 
 / 
 
 
 
 16.2 
 
 
 
 
 16.6 
 
 
 
 
 15.0 
 
 1 
 
 
 
 14.4 
 
 1 
 
 
 
 13.8 
 
 \ 
 
 
 
 13.2 
 
 \ 
 
 
 
 12.6 
 
 \ 
 
 
 
 12.0 
 
 \ 
 
 
 
 01.4 
 
 ►^10.8 
 |l0.2 
 M 0.6 
 
 \ Phenyl-di-chlor-Arsine Detonations 
 
 \ Curve No. 1-2 gm. Phenyl-di-chlor-arsine 
 
 \ Curve No. 2-5 gm. Phenyl-di-chlor-arsine 
 
 A \ Curve No. 3-1 gm. Phenyl diofclor-arsine 
 
 ^ \ Curve No. 4-0. 5gm. Phenyl-di-chlor-arsine 
 
 ft \ Curve No 5-3 gm. Phenyl-di-chlor.arsinc 
 
 E 8.4 
 |,.8 
 = 7-2 
 " 6.6 
 
 l\\ 
 
 
 ^o.6 Detonators 
 
 6.0 
 
 - \ \ \ 
 
 
 
 5.4 
 
 - V \ \^ 
 
 
 
 4.8 
 
 \\ \\ N. 
 
 
 
 4.2 
 
 \/\\\. \^ 
 
 
 
 3.6 
 
 ^v>^>^ 
 
 X 
 
 . 
 
 • 3.0 
 
 \s^^ x:^ 
 
 ^ 
 
 ^\^ 
 
 2.4 
 
 ^\^^ 
 
 
 ^^^"^^^ZT""^^-^ 
 
 1.8 
 1.2 
 .6 
 
 
 
 ^^""^-^5 * 3 
 
 Fig. 101.- 
 
 2 4 6 81012141G182022242G2S30;J23-43C3S4042444C4850o254565860 
 Time-lliiiutea 
 
 -Typical Curves Showing the Decrease in Concentration 
 Cloud with Time. 
 
 of Smoke 
 
 ^ 
 
 Toxic Materials 
 
 The selection of materials for the production of toxic smokes 
 can only be carried out experimentally. A number of very toxic 
 substances have been shown to be valueless as toxic smokes 
 because of low penetration, decomposition during the process of 
 smoke production, or for other reasons. 
 
318 CHEMICAL WARFARE 
 
 Arsenic compounds produce smokes distinctly better than the 
 average. Inorganic compounds which have high melting and 
 boiling points are very poor smoke producers. The only excep- 
 tion to this is magnesium arsenide, which may suffer decom- 
 position. Compounds like mercuric chloride and arsenic tri- 
 bromide, which boil or sublime at comparatively low tempera- 
 tures, produce good smokes. Most materials which boil below 
 130° C. produce no smoke as they evaporate on dispersion. It is 
 difficult to set any upper limit for the boiling point beyond which 
 materials do not produce good smokes, but in all probability 
 500° C. is not far from the maximum. Liquids and solids are, 
 on the whole, almost equally good as smoke producers. The 
 physical condition of the material has no great effect upon the 
 amount of smoke which it will produce. This seems to depend 
 only upon the physical and chemical properties of the material. 
 
 Toxic Smoke Apparatus 
 
 It has been mentioned above that the Germans used a shell, 
 containing solid diphenylchloroarsine and a high explosive. A 
 10.5 cm. shell (Blue Cross) was about two-thirds filled with cast 
 trinitrotoluene and contained a glass bottle with 300-400 grams 
 of toxic material. Diphenylchloroarsine was also used in shell, in 
 solution, a mixture of phosgene and diphosgene (superpalite) 
 being the ordinary solvent (Green Cross). Mixtures of di- 
 phenylchloroarsine and phenyldichloroarsine were also used. 
 
 In the case of high explosive shell, the use of a separate con- 
 tainer appears to be desirable, because a mixture with the ex- 
 plosive seriously decreases its sensitiveness and even its destruc- 
 tive power. There is also a question as to the stability of such a 
 mixture. However, 75 mm. shell containing 30 per cent di- 
 phenylchloroarsine mixed with T. N. T. gave good clouds of toxic 
 smoke. 
 
 Toxic Smoke Candle -^ 
 
 Two toxic smoke candles were developed by the Chemical 
 Warfare Service, known as the B-M Toxic Smoke Candle, per- 
 fected by the Pyrotechnic Section of the Research Division, 
 and the Dispersoid Smoke Candle, developed by the Dispersoid 
 Section. 
 
TOXIC SMOKES 
 
 319 
 
 The B-M Toxic Smoke Candle consists of a bottle-shaped 
 sheet-steel toxic container set into a can, containing smoke 
 mixture. The heat from the burning mixture causes the dis- 
 tillation of the toxic material. The toxic vapor is discharged 
 through a nipple, screwed into the neck of the container and 
 extending over the top of the smoke can. Steel wool is used 
 in the toxic container to reduce the violent boiling and spat- 
 tering of the material. A small amount of steel wool, held in 
 
 Fig. 102— Toxic Smoke Cloud from 500 D. M. Candles. 
 
 The candles were placed in 5 parallel rows which were 2 yards apart, each row contain- 
 , ing 100 candles on a 100 yard front. The total time of active smoke emission was 
 
 23 minutes. 
 
 place by a wire screen, is also used in the nipple for the same 
 purpose. The toxic container is sealed by a fusible metal plug, 
 melting at 90° C, cast into a retainer at the base of the nipple. 
 The fusible plug melts upon the first application of heat and 
 allows free passage of the vapor into the smoke cloud. The 
 ignition of the apparatus is effected by means of a simple match 
 head and an accompanying scratcher. 
 
 The first evolution of smoke occurs about 10 seconds after 
 tlie first appearance of flame. About one minute after ignition 
 the toxic material will begin to distill into the smoke cloud 
 
320 CHEMICAL WARFARE 
 
 and this will continue for about four minutes. The burning 
 of the candle should be complete in about six minutes. 
 
 The Dispersoid Toxic Smoke Candle differs from the B-M 
 candle in that the toxic container is not used. A mixture of 
 smokeless powder and the toxic material (diphenylchloroarsine 
 or D. M., an arsenical obtained from arsenic trichloride and 
 diphenylamine) is filled directly into the container, a cylindrical 
 can 3.5 inches in diameter and 9 inches high made from 27 gauge 
 sheet metal, and packed under a total pressure of 2,500 pounds. 
 The top of the candle is a metal cover, containing the match head 
 scratcher, which is separated from the match head by a Manila 
 
 \ 
 
 Dispersoid Candle British Candle 
 
 Fig. 103.— Comparison of Dispersoid and British D. M. Candles. 
 
 paper disc. These are the same as those used in the B-M 
 candle. The candle has a total weight of about 4.25 pounds, 
 of which 3.6 pounds are the smoke mixture, containing about 
 1.3 pounds of toxic material. 
 
 In operating the candles, the cover is removed and the 
 match head ignited by friction with the scratcher. The match 
 head burns through the cardboard and ignites the powder. The 
 heat and gas produced by the combustion of the powder vapor- 
 izes the particles of the toxic material and carries the vapors 
 out through the orifices at a high velocity whereupon they 
 recondense to form a smoke. The rapid emission of the vapors 
 through the orifice prevents any possibility of their ignition. 
 
 The time before good emission of smoke takes place after 
 
TOXIC SMOKES 321 
 
 the ignition of the match tip of a candle is 30 seconds. The 
 average time of vigorous smoke emission is from four to five 
 minutes. The result of a field test with the dispersoid candle 
 is shown in Fig. 102. A comparison of a British and a Disper- 
 soid candle is shown in Fig. 103. It should be stated that this 
 may not have been a fair test as only one British candle was 
 available for the comparative test. 
 
CHAPTER XVIII 
 SMOKE FILTERS 
 
 The first types of the Standard Box Eespirator contained 
 cotton pads, which sufficed to remove the ordinary smoke of 
 the battlefield and even that from the earlier toxic materials. 
 Improved methods of producing toxic smokes, by means of 
 which smaller particles were obtained, led, early in 1918, to 
 the recognition of the need of improved protection against 
 these smokes. The first attempts to meet this need consisted 
 in improving the filtering qualities of these pads. It was soon 
 found, however, that to make better filter pads would greatly 
 increase the total resistance of the canister. This was highly 
 undesirable, since the resistance of the ordinary canister was 
 already so high as to be very uncomfortable. To overcome 
 this objection, some of the early designs of filter canisters 
 were provided with a mechanical valve, which could be operated 
 by hand, to by-pass the air around the filter when the canister 
 was used against gas alone, or so set as to make the air pass 
 through the filter when smoke was feared. This introduced 
 a factor of uncertainty among the men during a gas attack, 
 since each man must decide for himself whether smoke was 
 present. This reason alone was sufficient for discarding this 
 design. 
 
 A preliminary study of the situation indicated that any 
 filter for fine smoke particles must have a high resistance per 
 unit of area, but that the total resistance must be compara- 
 tively low. In order to secure the large area necessary to 
 bring the total resistance within reason, the experimental work 
 was developed along three lines : The formation of a filter into 
 a bag, cup, or jacket to surround the outside of the canister; 
 the use of an arrangement sufficiently compact to go inside 
 
 322 
 
SMOKE FILTERS 
 
 323 
 
 the canister; and the use of a filter as a separate unit, to be 
 attached to the canister by an air connection. 
 
 A survey of the possible filtering materials indicated that 
 only two offered promise, namely, paper and felt. 
 
 Paper Filters 
 
 Reports that the British had developed thin, creped, sulfite- 
 cellulose wood pulp paper for filters led to an intensive study 
 of this material by the Chemical Warfare Service. 
 
 'Fig. 104, — Crepe Paper Doughnut Filter Canister. 
 
 In general we may say that the development of paper filters 
 (in sheet form) met with little success. Papers affording the 
 required protection did not live up to the resistance specifica- 
 tions. The reason for this probably is in the method of making 
 paper. The pulp is fed onto the screen of a Fourdrinier 
 machine under conditions that do not permit of uniformity 
 in the distribution of the fibers and consequently there is no 
 uniformity in the size of pores. In order to eliminate the 
 large holes, which allow the smoke to pass readily, the paper 
 
324 CHEMICAL WARFARE 
 
 must be pressed to reduce these pores to the proper magnitude. 
 This naturally results in an approximately equal decrease in 
 the size of the small pores, with a consequent increase in the 
 final resistance out of all proportion to the protection gained. 
 A very satisfactory paper was finally produced, but the resist- 
 ance was too high and it was necessary to increase the total 
 available filtering area, which resulted in the accordion type 
 of filter. This filter was incapable of development on a large 
 scale because of the large amount of hand work required in 
 assembling. The lack of uniformity in a single sheet has been 
 overcome with some success by making up a filter from 40 to 
 80 layers of tissue or crepe paper, trusting that the law of 
 chance would bring the large pores in some successive layer. 
 Such a filter was adopted by the British, but since it did not 
 give protection comparable with that aij^orded by felt filters, 
 it was rejected in the United States. 
 
 In the so-called '* doughnut" filter use was made of tissue 
 paper. Instead of seeking for uniformity in a vertical direc- 
 tion through a block of tissues, it was sought along the axis 
 horizontal with the sheet. The effectiveness of such a filter 
 was less than that of felt. In addition, serious difficulty was 
 met in cutting the pile of tissue paper into the proper shape 
 so that eventually it was abandoned as a production possibility. 
 
 Felt Filters 
 
 Work on the felt filters started about June, 1918. Great 
 difficulties were met in the beginning, as a felt satisfactory 
 for this purpose must be made under carefully controlled 
 conditions and production conditions during the war did not 
 readily lend themselves to such control. However, the oppor- 
 tunities afforded in felt making for uniform packing and 
 arranging of the fibers (the whole process of making a felt 
 is one of gradual packing of fibers into a relatively small 
 volume) are such as to assure a greater degree of success 
 than is the case in paper making. 
 
 Very successful filters have been obtained with the use 
 of felt. There are two serious objections to its use, however. 
 The first is the great cost of the filter (this was above one 
 
SMOKE FILTERS 
 
 325 
 
 dollar per filter at the close of the War) ; the second is that 
 felt is a valuable industrial commodity. It is thus very desir- 
 able that a cheaper and a less important industrial material be 
 found. 
 
 The 1919 Canister 
 
 Just before the Armistice, the Gas Defense Long Island 
 Laboratory brought out the so-called ''1919 Canister," which 
 consisted of an oval section, perforated metal, war gas material 
 
 Fig. 105.— 1919 Felt Filter Canister. 
 
 container with a central, flat, perforated breathing tube con- 
 nected to a nozzle at one end. (See also page 228.) After this 
 inner container is packed with the war gas chemicals, a filter 
 jacket is slipped over it and the top edge sealed to the inner 
 container. 
 
 Attempts were made to put paper filters on this canister 
 
326 CHEMICAL WARFARE 
 
 by wrapping it with layers of paper. In some cases, layers 
 of coarse burlap or mosquito netting were applied between 
 the layers of paper to give mechanical strength and air space. 
 The fact that many filters gave good protection showed that 
 a filter of this type and material is possible, but the operations 
 of wrapping and sealing require careful work in production 
 and inspection and even with the greatest skill and care, 
 imperfections are almost impossible to avoid. This chance of 
 defects, together with the labor involved, makes the process 
 undesirable. 
 
 A Theory op Smoke Filters 
 
 Tolman, "Wells and Gerke, during the course of their work 
 on toxic smokes, developed the following theory of smoke 
 filters. 
 
 The phenomena occurring in the filtration of smoke are 
 exceedingly complicated, but the general nature of the process 
 may be simply described in terms of the kinetic properties of 
 the small particles comprising the smoke. 
 
 A filter may be regarded as a series of minute capillaries 
 through which the smoke slowly flows. In order that filtration 
 may take place, it is not necessary to assume that the capil- 
 laries of the filter are smaller than the particle, for the particles 
 may diffuse to the walls of the capillaries and it is believed 
 that with typical filters this is the actual method of smoke 
 removal for particles less than 10-* cm. in diameter. 
 
 In accordance with this view as to the nature of smoke 
 filtration, the important factors involved are (1) the Brownian 
 motion of the smoke particles, (2) the area and arrangement 
 of the internal surface presented by the filter, (3) the flow 
 of the smoke as a whole, and (4) the attractive forces between 
 the filter surfaces and the smoke particles. The first three 
 of these factors determine how many particles come within 
 the range of the mutual forces of the particle and filter surface, 
 and the fourth factor determines the chance or expectation 
 that the particle will permanently adhere to the surface of 
 the filter. 
 
I 
 
 tiMOKE FILTERS 327 
 
 Testing Smoke Filters 
 
 All the early tests made on smoke filters used diphenyl- 
 chloroarsine, because it was felt that the filter must be tested 
 against a toxic smoke. A man test was developed as repre- 
 sentative as possible of actual conditions in the field, and the 
 time necessary for a man to detect diphenylchloroarsine smoke 
 in the effluent stream when breathing at a normal rate, using 
 a carefully controlled concentration of smoke produced by 
 detonation, was used as the criterion of the protection offered 
 by the canister. This test was subject to extensive individual 
 variations, due to the varying physiological resistances of 
 different men to diphenylchloroarsine smoke. Further, it was 
 quite inadequate for rapid testing on a large scale. A testing 
 machine was then developed, which gave results comparable 
 with those obtained in the man test. The method used in 
 detecting the gas was physiological, that is, by smell or by 
 its irritating action towards the membranes of the eye. While 
 these are purely qualitative tests, they are much more sensi- 
 tive than any possible chemical tests. 
 
 Because of the desirability of having a method which could 
 be controlled chemically, other methods were developed. 
 
 Ammonium chloride is a solid smoke, consisting of particles 
 of quite variable sizes. It is sensitive to dilution and clogs 
 the pores of the filtering medium quite rapidly. For this 
 reason it was used in the study of the rate of plugging or 
 clogging of the filter (the closing of the pores of the fabric 
 or other material to the passage of air). 
 
 The smoke is produced by the reaction of ammonia and 
 hydrogen chloride-air streams. The smoke thus generated 
 is passed from the mixing chamber to a larger distribution 
 box and from there through the filter, at a standard rate. 
 The concentration of the smoke may be accurately determined 
 by chemical means or photometrically, using a Hess-Ives Tint 
 Photometer, the Marten Photometer, or a special photometer 
 developed by the Chemical Warfare Service. 
 
 A comparison of a large number of tests with those of 
 other smokes would indicate that ammonium chloride smoke 
 
328 
 
 CHEMICAL WARFARE 
 
 offers accurate information as to protection sought, but is 
 hardly a desirable smoke for testing on a large scale. 
 
 The third method developed was the sulfuric acid smoke. 
 This smoke was produced by passing dry air through a tower 
 of solid pieces of sulfur trioxide and then mixing the vapor 
 with a large volume of air at 50 per cent relative humidity. 
 It is not a clogging smoke and the filtering efficiency does 
 
 Fig. 106. — Tobacco Smoke Apparatus for Testing Canisters. 
 
 not change materially in the time of exposure required for a 
 test. The smoke lends itself easily to chemioal analysis and 
 offers data as to exact particulate cloud concentrations which 
 will penetrate canisters; photometric measurements are also 
 applicable. 
 
 The fourth method consists in the use of tobacco smoke. 
 This is generated by passing air over ignited sticks of a 
 mixture of tobacco (63 per cent), rosin (30 per cent) and 
 
I 
 
 SMOKE FILTERS 329 
 
 potassium nitrate (7 per cent). This smoke is composed of 
 particles of extreme uniformity in size; chemically it is rela- 
 itvely inert. It is not a clogging smoke and is not sensitive 
 to moisture and dilution. The density of the effluent smoke 
 is compared with that of the entering smoke in a Tyndall 
 beam, and the filtering capacity of the material determined 
 in terms of the amount of air necessary to dilute the entering 
 air to the same concentration of the effluent air. The method 
 is simple in manipulation and the test is a rapid one (50 
 canisters per day). Because of the apparent superiority of 
 tobacco smoke as a testing smoke, the accompanying disad- 
 vantages are possibly outweighed. 
 
 From the standpoint of inherent chemical properties, the 
 general desirability of a suitable testing smoke would decrease 
 in the following order: tobacco, sulfuric acid, ammonium 
 chloride. 
 
CHAPTER XIX 
 
 SIGNAL SMOKES 
 
 / The success of pyrotechnics in night signalling led, during 
 'the World War, to considerable attention being paid to the 
 development of pyrotechnic signals for day use. This was 
 mainly directed to the production of distinctive smokes, which 
 should have the same long range visibility under varying light 
 conditioils. Since a gray or white smoke might be confused 
 with the smoke produced accidentally by the explosion of 
 shell, it was necessary to use smoke of definite and unmistak- 
 able colors, and red, blue, yellow, green and purple smokes 
 were developed. During the early part of the war, only a 
 yellow smoke was in use, though others were added later. 
 
 Production of Colored Smokes 
 
 There are three possible ways of obtaining signal smokes. 
 I. Mechanically dispersing solids. 
 II. Chemical Reaction. 
 
 III. Volatilization of colored materials. 
 
 I^ The first method, while possible, can never be an efficient 
 method of producing signals. Some success was met with in 
 dispersing certain inorganic materials, as rouge, and ultrama- 
 rine, in projectiles fired from a 3-inch mortar and exploded by 
 a time fuse arrangement at the height of their flight. Various 
 mixtures were also tried, such as antimony oxysulfide and 
 aluminum powder (red), arsenic and antimony trichlorides 
 with sodium thiosulfate (yellow), etc., but these compositions 
 have the disadvantages of being liable to catch fire if dispersed 
 by a black powder explosion. 
 
 II. While colored smokes may be produced by chemical re- 
 action, such as the combination of hydrogen iodide (HI), chlor- 
 
 330 
 
I 
 
 SIGNAL SMOKES 331 
 
 ine and ammonia, the clouds are not satisfactory as signals. In 
 this particular case, the purple cloud (to the operator in the 
 aeroplane) appeared white to the observers on the ground. 
 
 High temperature combustion smokes have also been studied. 
 These are used in the so-called smoke torches. The yellow arsenic 
 sulfide smoke is the most widely used. Most formulas call for 
 some sulfide of arsenic (usually the native realgar, known com- 
 mercially as '*Eed Saxony Arsenic"), sulfur, potassium nitrate, 
 and in some cases, a diluent like ground glass or sand. A typical 
 mixture consists of: 
 
 Red arsenic sulfide 55% 
 
 Sulfu^ 15% 
 
 Potassium nitrate 30% 
 
 A very similar smoke may be obtained from the following 
 mixture : 
 
 Sulfur 28.6% 
 
 White arsenic 32.0% 
 
 Potassium nitrate 33 .8% 
 
 Powdered glass 6.6% 
 
 These smokes are not as satisfactory in color as the smoke 
 produced by a dye smoke mixture, especially when viewed from 
 a distance, with the sky as a background. They fade out rather 
 quickly to a very nearly white smoke. 
 
 A black smoke upon first thought might seem to be the 
 easiest of all smokes to produce, but actually the production of a 
 black smoke that would be satisfactory for signalling purposes 
 was rather a difficult matter. 
 
 Starting with the standard smoke mixture, which gives a 
 white or gray smoke, hexachloroethane, which is solid, was sub- 
 stituted for the carbon tetrachloride, in order to avoid a liquid 
 constituent. Naphthalene was first used, until it was found that 
 the mixture of naphtalene and hexachloroethane melted at tem- 
 peratures below that of either of the constituents. Anthracene 
 was then substituted. The principal reaction is between the 
 magnesium and the chlorine-containing compound, whereby 
 magnesium chloride and carbon are formed. The reaction is 
 very violent, and a white smoke is produced. The anthracene 
 slows down the reaction and at the same time colors the smoke 
 
332 CHEMICAL WARFARE 
 
 black. The speed of the reaction may be controlled by varying 
 the anthracene content. 
 
 In burning this type of smoke mixture in a cylinder, it is 
 essential that free burning be allowed. It has been found that if 
 combustion is at all smothered, and the smoke forced to escape 
 through a comparatively small opening, it will be gray instead 
 of dense black. 
 
 III. Various attempts have been made to utilize the heat 
 evolved when the Berger type smoke mixture reacts to volatilize 
 or mechanically disperse various colored inorganic substances, 
 and especially iodine. These were unsuccessful. Modifications, 
 such as 
 
 Strontium nitrate 1 part 
 
 Powdered ircn 2 parts 
 
 Iodine 3 parts 
 
 were also tried, but while such mixtures ignited easily, burned 
 freely and evenly, and gave a continuous heavy purple cloud, 
 they were very sensitive to moisture and capable of spontaneous 
 ignition. 
 
 The most satisfactory and successful colored smokes arc 
 those produced by the volatilization of organic dye materials. 
 This practice seems to have originated with the British, who 
 produced such smokes by volatilizing cr vaporizing special dyes 
 by igniting mixtures of the dye, lactose and potassium chlorate 
 and smothering the combustion. 
 
 In selecting dyestufPs for this purpose it was at once recog- 
 nized that only those compounds can be used which are 
 volatilized or vaporized without decomposition by the heat 
 generated when the mixture is ignited and the combustion 
 smothered. It was also found that the boiling point and melting or 
 volatilization point of the colored compound must be close enough 
 together so that there is never much liquid dye present. Since 
 all colored organic compounds are destroyed if subjected to 
 sufficient heat, the mixture must be so prepared and the ignition 
 so arranged that the heat generated is not sufficient to cause this 
 destruction. 
 
 The oxidizing agents used in the combustion mixture may be 
 either potassium or sodium chlorate. The nitrate is not satisfac- 
 
SIGNAL SMOKES 333 
 
 toiy. Lactose has proven the best combustible. Powdered 
 orange shellac is fairly satisfactory but offers no advantage over 
 lactose. 
 
 The following dyes have been found to give the best smokes : 
 
 Red "Paratoner" 
 
 Yellow Chrysoidine+Auramine 
 
 Blue Indigo 
 
 Purple Indulin (?) 
 
 Green Auramine Yellow +Indigo 
 
 At the beginning of the war, the only colored smoke used by 
 the United States Army was a yellow smoke. The smoke mixture 
 used in all signals, excepting the smoke torch, was the old arsenic 
 sulfide mixture. The following smoke signals were adopted dur- 
 ing the World War : 
 
 Signal Parachute Rocket Yellow and Red 
 
 V. B. Parachute Cartridge Yellow 
 
 25 mm. Very Parachute Cartridge Yellow 
 
 35 mm. Signal Cartridge Yellow 
 
 35 mm. Signal Cartridge Red 
 
 35 mm. Signal Pistol 
 
 25 mm. Very Signal Pistol 
 
 V. B. Rifle Discharger Cut 
 
 The Tactical Use of Signal Smokes 
 
 From the days when Horatius kept the bridge, down through 
 the centuries to the World War, all leaders in battle were 
 pictured at the front and with flaming sword, mounted on 
 magnificent chargers, or otherwise so prominently dressed that 
 all the world knew they were the leaders. During all these* 
 hundreds of years commands on the field of battle were by the 
 voice, by the bugle, or by short mnge signals with arms, flags, 
 and swords. Even where quite large forces were involved they 
 were massed close enough ordinarily so that signalling by such 
 means sufficed to cover the front of battle. In those cases where 
 they did not, reliance was put upon swift couriers on horseback 
 or on foot. 
 
 With the invention of smokeless powder and the rifled gun 
 battles were begun and carried on at greater and greater ranges. 
 Artillery fired not only 2,000 to 3,000 yards but up to 5,000 and 
 
334 CHEMICAL WARFARE 
 
 10,000 yards, or even, as in the World War, at 20,000 yards and 
 more. It was then that other means of signalling became essen- 
 tial. Distant signalling with flags is known to have been prac- 
 ticed to a certain extent on land for a long time. The extension 
 of the telegraph and telephone through insulated wires laid by 
 the Signal Service was the next great step in advance, and in 
 the World War there came in addition the wireless telephone 
 both on land and in aeroplanes and balloons. 
 
 Along with this development, as mentioned under Screening 
 Smokes, came the development of the use of smoke for protection 
 and for cutting off the view of observers, thus making obser- 
 vation more and more difficult. This use of smoke, coupled with. 
 the deadly fire of machine guns and high explosives, forced men 
 to take shelter in deep shell holes, in deep trenches and other 
 places that were safe, but which made it nearly impossible to 
 see signals along the front of battle. 
 
 Every man can readily be taught to read a few signals when 
 clearly indicated by definite, sharply defined colored smokes. 
 At first these were designed for use on the ground and will be 
 used to a certain extent in the future for that purpose, par- 
 ticularly when it is desired to attract the attention of observers 
 in aeroplanes or balloons. In such cases a considerable volume of 
 smoke is desired. For the man in the trench or shell hole some 
 means of getting the signal above the dust and smoke of the 
 battlefield is needed. It is there that signal smokes carried by 
 small parachutes, contained in rockets or bombs, have proven 
 their worth. These signals floating high above the battlefield 
 for a minute or more, giving off brilliantly colored smokes, 
 afford a means of sending signals to soldiers in the dust and 
 smoke of battle not afforded by any other method so far invented. 
 As before stated, every man can be taught these simple signals, 
 where but very few men can be taught to handle even the 
 simplest of wireless telephones. 
 
 Thus, smoke has already begun to complicate, and in the 
 future will complicate still more, every phase of fighting. It 
 will be used for deception, for concealment, for obscuring vision, 
 for signalling and to hide deadly gases. The signal rocket will 
 be used to start battles, change fronts, order up reserves, and 
 finally to stop fighting. 
 
SIGNAL SMOKES 335 
 
 The signal smokes by day will be displaced at night by 
 brilliantly colored lights which will have the same meaning as 
 similarly colored smokes during the day. Thus, literally, smoke in 
 the future will be the cloud by day and the pillar of fire by night 
 to guide the bewildered soldier on the field of battle with all its 
 terrors and amidst the confusion, gas, smoke and dust that will 
 never be absent while battles last. 
 
CHAPTER XX 
 INCENDIARY MATERIALS 
 
 Since it is generally known that white phosphorus, when 
 exposed to the air, takes fire spontaneously, it logically follows 
 that numerous suggestions should have been made for using this 
 material in incendiary devices. Practice, however, has shown 
 that, while phosphorus is undoubtedly of value against very 
 easily ignitable materials, such as hydrogen in Zeppelins, or the 
 gasoline tanks of aeroplanes and dry brush or grass, it is of 
 much less value when wood and other materials are considered. 
 This is partly because of the low temperature of burning, and 
 partly because the product of combustion (phosphoric anhy- 
 dride) is really an excellent fireproofing substance. In view of 
 this, phosphorus was used primarily for smoke production. 
 
 A superior incendiary material is found in thermit, a mixture 
 of aluminum and iron oxide. When ignited, it produces an 
 enormous amount of heat very quickly, and the molten slag that 
 results from the reaction will prolong the incendiary action upon 
 inflammable materials. When used alone, however, it has the 
 disadvantages that the incendiary action is confined to a small 
 area and that the heat energy is wasted because of the fact that 
 it is so rapid in its action. 
 
 For this reason it is customary to add a highly inflammable 
 material, which will become ignited by the thermit and will con- 
 tinue the conflagration. Petroleum oils, carbon ■ disulfide, wood 
 distillation products and other inflammable liquids were thor- 
 oughly tested for this purpose. The final conclusion was reached 
 that oil, solidified with soap (sodium salts of the higher fatty 
 acids) by a special method developed by the Chemical Warfare 
 Service, was by far the best material to be used. In certain tests, 
 using a combination of thermit and solid oil, flames fifteen feet 
 high were obtained, which would be very useful against walls, 
 ceilings, etc. 
 
 336 
 
INCENDIARY MATERIALS 337 
 
 In addition to this type of incendiary material, it was desir- 
 able to have a spontaneously inflammable mixture of oils, whicli 
 could be used in Livens' shell, Stokes' shell or aeroplane bombs. 
 The basis of these mixtures is fuel oil and phosphorus. By vary- 
 ing the proportions of the constituents it is possible to obtain a 
 mixture that will ignite immediately upon exposure to the air, 
 or one that will have a delayed action of from 30 seconds to two 
 minutes. 
 
 The incorporation of metallic sodium gives a mixture that 
 will ignite when spread upon water surfaces. 
 
 Incendiary Devices 
 
 The incendiary devices used during the Ikte war included 
 bombs, shell, tracer shell and bullets, grenades, and flame 
 throwers. 
 
 Bombs 
 
 Incendiary bombs were used almost exclusively by aircraft. 
 The value of bombs which would cause destruction by starting 
 conflagrations was early recognized but their development was 
 rather slow. "While the designs were constantly changing, two 
 stand out as the most favored : a small unit, such as the Baby 
 Incendiary Bomb of the English, and a large bomb, such as the 
 French Chenard bomb or the American Mark II bomb. 
 
 In general bombs which, when they function upon impact, 
 scatter small burning units over a considerable area, are not 
 favored. Small unit bombs can be more effectively used 
 because the scatter can be better regulated and the incendiary 
 units can be more advantageously placed. 
 \ German Bombs. Incendiary bombs were used by the Ger- 
 mans in their airplane raids, usually in connection with higli 
 explosive bombs. A typical armament of the later series of 
 German naval airships consisted of the following: 
 
 2 660-pound bombs 
 10 220-pound bombs 
 15 110-pound bombs 
 20 Incendiary bombs 
 
 making a total weight of about 2^^ tons. 
 
338 
 
 CHEMICAL WARFARE 
 
 A typical German bomb is shown in Fig. 108. It consists 
 essentially of a receiver of white iron (r) composed of a casing 
 and a central tube of zinc, joined together in such a fashion 
 that, when the whole was complete, it had the appearance 
 of an elongated vessel with a hollow center. Within this 
 
 Fig. 107 — Incendiary Devices. 
 
 (From Left to Right). Mark II Bomb, B. I. Bomb, Mark I Dart, Mark II Dart, 
 Mark I Dart, Grenade, Mark I Bomb. 
 
 central hollow is placed a priming tube (t) of thin sheet iron, 
 pierced by a number of circular openings. The receiver is 
 about 445 mm. (17.5 in.) high and 110 mm. (4.3 in.) at its 
 maximum diameter. It is wrapped with strands of tarred 
 cord over nearly its entire length. The empennage (270 mm. or 
 
INCENDIARY MATERIALS 
 
 339 
 
 10.6 in. — in height) consisted of three inclined balancing fins, 
 which assured the rotation of the projectile during its fall. 
 
 In the body of the bomb was a viscous mass of benzine 
 hydrocarbons, while the lower part of the receiver contained 
 a mixture of potassium perchlorate and paraffin. The central 
 tube apparently contained a mixture of aluminum and sulfur. 
 
 Later the Germans used a scatter type of bomb (Fig. 109) 
 which was designed to give 46 points of conflagration. Each 
 
 I 
 
 
 I 
 
 f 
 
 
 /T 
 
 'i 
 
 
 E \ 
 
 M 
 
 a- 
 
 _0 
 
 ij^. 
 
 ^^; 
 
 iJ- 
 
 
 1- o(,- 
 
 "1 
 
 
 1 
 
 1 
 
 c- 
 
 1 
 
 tt 
 
 
 hi 
 
 J 
 
 
 li 
 
 3^ 
 
 1 
 
 1 
 
 u 
 
 r 
 
 \Jlf 
 
 TJ 
 
 
 V \ 
 
 T 
 
 \7 
 
 ^ 
 
 
 V 
 
 y 
 
 ^ 
 
 Section at a 6 
 
 All DtmensionB in ICnUmeteri 
 
 Fig. 108. — Aerial Incendiary Bomb, 
 November, 1916. 
 
 ning Fuze 
 
 Lighter 
 
 Fig. 1C9. — German Incendiary 
 Bomb, Scatter Type. 
 
 of these 46 small cylinders contained 50 grams of an air 
 incendiary material. They were arranged in layers, packed 
 in with very fine gun powder. The bomb is ignited by a fric- 
 tion lighter which is pulled automatically when the bomb is 
 released from the aeroplane. The bomb is constructed to burst 
 in the air and not on striking the ground. The upper part 
 of the projectile consists of a cast iron nose riveted to the 
 sheet iron body of the bomb. When the explosion occurs, the 
 nose is blown away and the small incendiary cylinders are 
 scattered in the air. . 
 
340 CHEMICAL WARFARE 
 
 The incendiary material appears to be a mixture of barium 
 nitrate and tar. Its incendiary power is very low because 
 combustion takes the form of a small flame of very short 
 duration. It should, however, be very . valuable for firing 
 inflammable materials. 
 [ British Bombs. The early British bombs were petrol bombs, 
 
 Hwhich were used without great success for crop burning. 
 Phosphorus bombs were then used for attacking aircraft. But 
 the most successful incendiary is the so-called ''Baby Incen- 
 diary Bomb." This is a 6.5-ounce bomb with an incendiary 
 charge of special thermit. These small bombs are car- 
 ried in containers holding either 144 or 272 bombs. The 
 former container approximates in size and weight one 50-pound 
 lI.E. bomb and the latter one 120-pound H.E. bomb. The bomb 
 contains a cartridge very much like a shot gun shell which, 
 on impact, sets down on the striker point in the base of the 
 body, and causes the ignition of the charge. It is claimed 
 that the cartridge of the B.I. bomb burns when totally im- 
 mersed in any liquid (water included) and in depths up to 
 two feet the flame breaks through the surface. 
 
 \l French Bombs. The French used three types of incendiary 
 ftombs, a special thermit (calonite), the Chenard and the 
 Davidsen. The Chenard bomb is a true intensive type and is 
 thought to be very successful. It functions by means of a 
 time fuse operated by the unscrewing of a propeller, before 
 striking the ground, and reaches its target in flames. Its 
 chief disadvantage is the small amount of incendiary material 
 which it carries. The Davidsen bomb expels its charge as a 
 single unit and is not considered as valuable or as successful 
 as the Chenard. 
 
 K [ American Bombs. The program of the Chemical Warfare 
 service included three types of bombs: 
 
 Mark II Incendiary drop bomb 
 Mark III Incendiary drop bomb 
 Mark I Scatter bomb 
 
 ^ Mark II Bomb. The incendiary Mark II drop bomb is 
 designed to be dropped from an aeroplane and is intended for 
 use against buildings, etc., when penetrating effect followed 
 by an intensive incendiary action is sought. 
 
INCENDIARY MATERIALS 341 
 
 The bomb case consists of two parts: a body and a nose. 
 The body is a tapering zinc shell which carries the firing 
 mechanism and stabilizing tail fin at the small end and at the 
 large end a threaded ring which screws into the nose. The 
 nose is of drawn steel of such shape as to have low end-on 
 
 .^^1^^ , 
 
 1.--.^' iaiitiirti,iii ii i kri .J J! 
 
 
 I m 
 
 h-lSb 
 
 (■■Up ,',• iBw^ wim-'^-c^^ 
 
 i«# 
 
 ' ^ < iifjjll^ 
 
 IPM^^^n 
 
 m' 
 
 ^/m ^ww' V^^^^*^^PI^ V 
 
 f 
 
 
 Fig. 110. — Loading Bombs with "Solid" Oil. 
 
 resistance and is sufficiently strong to penetrate- frame 
 structures. 
 
 The incendiary effect is produced by a thermit charge car- 
 ried in the nose of the bomb. This charge is ignited by a 
 booster of ''Thermit Igniter" fired by black powder. The 
 latter is ignited by a flash from the discharge of a standard 
 
342 CHEMICAL WARFARE 
 
 0.30 caliber service cartridge contained in the body of the bomb, 
 and exploded by a firing mechanism of the impact type. This 
 method of firing has proven wholly unsatisfactory and will be 
 superseded by some more direct-acting mechanism. The body 
 of the bomb is filled with solidified oil. The molten thermit 
 burns through the case of the bomb and liberates the oil which 
 has been partially liquefied by the heat of the thermit reaction. 
 Additional incendiary effect is afforded by the sodium nitrate 
 contained in the nose below the thermit, and by two sheet 
 lead cylinders filled with sodium and imbedded in the solid 
 oil. The sodium increases the difficulty of extinguishing the 
 fire with water. 
 
 Mark III Bomb. This bomb is simply a larger size of the 
 Mark II bomb, its weight being approximately 100 pounds 
 as compared with 40 pounds for the Mark II bomb. It is 
 designed to be dropped from an aeroplane and is intended for 
 use against buildings when marked penetrating effect is 
 desired. The method of functioning is the same as the Mark 
 II bomb and it has the same defects in the firing mechanism. 
 Mark I Bomb (Scatter Type). The Mark I incendiary drop 
 bomb is also designed to be dropped from aeroplanes and is 
 intended for use against grain fields, ammunition dumps, light, 
 structures or similar objectives when only a low degree of 
 ignition is required. It is of the so-called scatter type, due 
 to the action of the exploding charge which casts out incen- 
 diary material within a radius of 20 feet from the point of 
 contact. 
 
 The incendiary action is due to the ejection of the various 
 incendiary units in the bomb by the explosion of the black 
 powder in the nose. The flash of this explosion serves to 
 ignite the units. A powder charge in the rear of the bomb acts 
 simultaneously with the nose charge, opening the bomb casing, 
 and aiding materially in the scatter of the units. The bomb 
 is so arranged as to function close to the ground, which is a 
 further factor in the scatter of the units. 
 
 The incendiary units are waste balls about 2.5 in. in diameter 
 and having an average weight of 2.5 ounces, tied securely 
 with strong twine. These are soaked in a special oil mixture. 
 Carbon disulfide and crude turpentine, or carbon disulfide, 
 
INCENDIARY MATERIALS 343 
 
 benzene heads and crude kerosene gave satisfactory results. 
 A later development attempted to replace the waste balls by 
 solid oil, but the difficulties of manufacture and questions of 
 transportation argued against its adoption. 
 
 These bombs were not used at the front. Nearly all of 
 the American incendiary bombs proved too light on the nose 
 and lower half, generally resulting in deformation upon impact 
 and very poor results. New ones will be made stronger. 
 
 Incendiary Darts \j 
 
 The British early recognized the value of a small bomb, 
 and consequently adopted their B.I.B. (Baby Incendiary 
 Bomb), weighing about 6.5 ounces. These are capable of being 
 dropped in lots of 100 or more and thus literally shower a 
 given territory with fire. The intensity of fire at any given 
 point is much less than that obtained with the larger bombs, 
 but the increased area under bombardment more than counter- 
 balances this disadvantage. While the British aimed at the 
 perfection of a universal bomb, the American service felt that 
 two classes should be developed, one to be used against grain 
 fields and forests, the other against buildings. 
 
 The first class was called the Mark I Dart. This consisted 
 of an elongated 12-gauge shot gun shell, filled with incendiary 
 material and provided with a firing mechanism lo ignite the 
 primer as the dart strikes the ground. The flash of the primer 
 sets fire to the booster, which, in turn, ignites the main incen- 
 diary charge. The latter burns several minutes, with a long 
 flame. A retarding stabilizer attached to the tail of the dart 
 serves the two-fold purpose of insuring the functioning of 
 the flring mechanism and, by retarding the final velocity of 
 the dart, preventing the collapse of the dart body when 
 dropped from very high altitudes. 
 
 The incendiary mixture is one which gives a long hot flame, 
 burns for several minutes and leaves very little ash. In general 
 it consists of an oxidizing agent (barium or sodium chlorate), 
 a reducing agent (aluminum, or a mixture of iron, aluminum 
 and magnesium), a filler (rosin, powdered asphaltum or naph- 
 thalene) and in some cases a binder (asphaltum, varnish or 
 boiled linseed oil). 
 
344 CHEMICAL WARFARE 
 
 The Mark II Dart was developed to furnish a small size 
 penetrating agent. It consists of a two-inch (diameter) zinc 
 case filled withlhermit and solid oil as the incendiary materials 
 and provided with a cast iron nose for penetration. During 
 the first half minute- after firing, a pool of molten iron is 
 formed by the thermit, which is very penetrating and affords 
 a good combustible surface for the oil, which burns for an 
 additional ten minutes. 
 
 It has an advantage over the Mark I dart in that it pene- 
 trates, and over the Mark II bomb in that it is smaller and 
 lighter in weight. 
 
 Incendiary Shell 
 
 Incendiary shell have been successfully/ used against ai^^ 
 craft and to some extent in bombardments of inflammable 
 ground targets. Anti-aircraft shell are of small caliber and 
 are usually tracer-incendiary. Such shell are filled with 
 pyrotechnic mixtures which ignite at the moment of firing, 
 or by time fuse, and are effective against highly inflammable 
 material. Shell filled with thermit which explode and scatter 
 the molten iron have been used against aircraft and ground 
 targets, but with rather poor results. Large shell, which burst 
 upon impact and scatter units of burning materials, have been 
 used with some success against ground targets. 
 
 Tracer shell contain such mixtures as barium nitrate, mag- 
 nesium and shellac, or red lead and magnesium. 
 
 Incendiary Bullets "\ \ 
 
 Incendiary bullets are only effective against highly inflam- 
 mable material, and are therefore used principally in aerial 
 warfare against aircraft, either for the purpose of igniting the 
 hydrogen of the gas bag, or the gasoline. The present tendency 
 is towards the use of the large size (11 mm.) bullet, because 
 of its greater incendiary action. 
 
 The incendiary material is either white phosphorus or a 
 special incendiary mixture consisting of an oxidizing agent 
 and some combustible or mixture of combustibles. The white 
 
INCENDIARY MATERIALS 345 
 
 tracer bullet contains a mixture of barium peroxide and mag- 
 nesium. A red bullet contained in addition, strontium nitrate 
 and chloride, or peroxide. 
 
 Incendiary Hand Grenade \f 
 
 While the use of incendiary grenades and oth|fer small incen- 
 diary devices is limited, sucli armament is considered very 
 valuable in trench warfare. They can be used to set fire to 
 inflammable material, either in offensive or defensive opera- 
 tions. 
 
 Phosphorus grenades, while used principally for producing 
 smoke (see page 302), have considerable value as an incendiary 
 weapon. 
 
 Thermit grenades are very useful in rendering unserviceable 
 guns and other metallic equipment which must be abandoned. 
 They permit aviators to destroy planes which motor troubles 
 oblige to land in enemy territory. They are also used to ignite 
 inflammable liquids, thrown into a dugout, or sprayed over an 
 objective by a flame projector. 
 
 The Mark I hand grenade was developed for burning enemy 
 ammunition dumps, for clearing away brush or other material 
 in front of trenches and for use in dugouts. The standard 
 n.E. grenade body was half-filled with thermit and half with 
 a celluloid container filled with a solidified fuel oil. The 
 grenade is fired by the spit of the fuse of the bouchon firing 
 mechanism. This, through the booster, lights the thermit 
 igniter, which in turn fires the main charge of thermit. The 
 resulting molten iron readily penetrates the grenade case, at 
 the same time igniting the celluloid case and its contents. The 
 oil burns for about 3.5 minutes. This grenade was never used 
 since it was considered that an all thermit grenade would be 
 of more value. 
 
 Trench Mortar Equipment 
 
 Special projectiles were designed for use witli the Stokes 
 mortar and the Livens' projector. Thermit was used only 
 in Stokes' projectiles. The Livens' projectile was filled with 
 
346 
 
 CHEMICAL WARFARE 
 
 inflammable units (chlorated jute) immersed in a light oil 
 mixture. Thrown from a projector into the enemy's trench, 
 it explodes, giving a large flash and scattering the burning 
 units over an area of forty yards. The Mark II projectile, 
 designed for general incendiary effect against readily inflam- 
 mable material, consists of an altered 8-inch Livens' gas projec- 
 tile filled with chlorated jute units impregnated with solid oil 
 
 Mild Steel-Copper Plated 
 Inside and Out 
 
 White FhoaporuB 
 
 Bed Varnish 
 
 725 > 
 
 Fig, 111. — German 8" Ircendiary Bullet. 
 
 r 
 
 'Lead 
 
 Small Glass 
 Bulb Filled with 
 -Sulphuric Acid 
 
 -Kolled Tin-Foil 
 -2.8 
 
 jCelluloid Tube 
 
 Filled with 
 
 Potassium 
 
 Chlorate 
 
 —Cork Plug 
 -Lead 
 
 Fig. 112. — German Incen- 
 diary Blue Pencil. 
 
 and immersed in a spontaneously inflammable oil. After a short 
 delay, these units burst into flame and burn vigorously for 
 several minutes. It is almost impossible to extinguish them 
 without large quantities of water. Such bombs have only a 
 very limited use, so that it is questionable if they are really 
 worth while. 
 
 German Blue Pencil 
 
 v\ 
 
 A very interesting and curious device was developed by 
 the Germans in the form of an incendiary pencil. Similar in 
 
INCENDIARY MATERIALS 347 
 
 appearance to a common blue pencil, sharpened at one end, 
 they are distinguished only by a small, almost imperceptible, 
 point placed on the outside 11 mm. from the unsharpened 
 end. They are 175 mm. long, 11.1 mm. in diameter and weigh 
 12 to 13 grams. The interior of the pencil contains a glass 
 Inilb, with two compartments filled with sulfuric acid and 
 I celluloid tube filled with potassium chlorate. The glass bulb 
 ends in a slender point; when this is broken the acid comes 
 into contact with the chlorate and causes an explosion. The 
 two materials are separated by a layer of clay, which causes 
 a delayed action of about 30 minutes. The operator breaks 
 the point of bulb, buries the pencil vertically in the inflam- 
 mable material and then has half an hour in which to got 
 away, before any possibility of a fire. He cuts the pencil 
 with a knife 2 cm. from the point, so that if caught he has 
 the appearance of simply sharpening a pencil. 
 
 Flaming Gun \ 
 
 Among the unsuccessful weapons of the late war, the liquid 
 fire gun or Flammenwerfer, as the German called it, is prob- 
 ably the most interesting. Its origin, according to a German 
 story, was due to a mere accident. A certain officer, during 
 peace maneuvers, was ordered to hold a fort at all cost. During 
 the sham fight, having employed all the means at his disposal, 
 he finally called out the fire brigade and directed streams 
 of water upon the attacking force. Afterwards, during the 
 criticism of the operations in the presence of the Kaiser, he 
 claimed that he had subjected the attackers to streams of 
 burning oil. The Kaiser immediately inquired whether such 
 a thing would be possible, and was assured that it was entirely 
 feasible. 
 
 Long series of experiments were necessary before a satis- 
 factory combination of oils was produced, which could be 
 projected as a flame on the enemy, but they were finally suc- 
 cessful. Unlike the use of poison gas, however, the flaming 
 liquid gun did not prove to be a successful weapon of warfare. 
 True, at first they were rather successful, but this was before 
 the men learned their real nature. In the first attack, the 
 
348 
 
 CHEMICAL WARFARE 
 
 Allies were completely surprised and the troops were routed 
 by the flames. Auld tells of one of the early attacks (July 29, 
 1915) when, without warning, the front line troops were 
 enveloped in ilames. Where the flames came from could not 
 
 be seen. All that the men knew was that they seemed sur- 
 rounded by fierce, curling flames, which were accompanied 
 by a loud roaring noise, and dense clouds of black smoke. 
 Here and there a big blob of burning oil would fall into a 
 trench or saphead. Shouts and yells rent the air as individual 
 
INCENDIARY MATERIALS 349 
 
 men, rising up in the trenches or attempting to move in the 
 open, felt the force of the flames. The only way to safety 
 appeared to be to the rear. This direction the men that were 
 left took. For a short space the flames pursued them and the 
 local retirement became a local rout. After the bombardment 
 which followed, only one man is known to have returned. 
 
 After a study of the pictures of the liquid fire gun in 
 operation, it is evident that the men could not be blamed for 
 tliis retirement. One has only to imagine being faced by a 
 sjHTad of flame similar to that used for the oil burners under 
 the largest boiler, but with a jet nearly 60 feet in length 
 and capable of being sprayed round as one might spray water 
 v/ith a fire hose. 
 
 Later, when the device was better known it was different, 
 though even then it was a pretty good test of a man's nerve. 
 It was found that the flames could not follow one to the 
 bottom of a trench as the gas did, and that, if a man crouched 
 to the bottom of his trench, his head might be very warm for 
 a minute or so but that the danger was soon past and he then 
 could pick off the man who had so recently made things 
 uncomfortable for him. 
 
 While it is said that Major R., who invented the Flammen- 
 werfer, enjoyed a great popularity among his men, and is 
 familiarly known as the Prince of Hades, there is no doubt 
 that this was not shared by the Allies. Their rule was: ** Shoot 
 the man carrying the apparatus before he gets in his shot, if 
 possible. If this cannot be done, take cover from the flames 
 and shoot him afterwards." 
 
 The German had several types, which may be grouped into 
 the small or portable and the krgre Flammenwerfers. 
 
 The portable Flammenwerfer consisted of a sheet steel 
 cylinder of two compartments, one to hold compressed 
 nitrogen, the other to hold the oil. The nitrogen furnished the 
 pressure which forces the oil out through the flexible tube. 
 Air cannot be used, because the oxygen would form an explo- 
 sive mixture with the vapors of the oil, and any heating on 
 compression, or back flash from the flame or fuse might make 
 things very unpleasant for the operator. A pressure of about 
 23 atmospheres is reached when the cylinder is charged. The 
 
350 
 
 CHEMICAL WARFARE 
 
 nitrogen appeared to be carried on the field in large containers 
 and the flame projectors actually charged in the trenches. 
 
 The oil used in the flame projectors varied from time to 
 time, but always contained a mixture of light or easily volatile 
 and heavy and less volatile fractions of petroleum or mineral 
 oil, very carefully mixed. In some cases even ordinary com- 
 mercial ether has been found in the cylinders. 
 
 The most interesting part about the flame projector is the 
 lighting device. This is so made that the oil ignites spon- 
 
 FiG. 114. — Small Flammenwerfer. 
 
 taneously the minute the jet is turned on, and is kept alight 
 by a fiercely burning mixture which lasts throughout the 
 discharge. This mixture is composed of barium nitrate, potas- 
 sium nitrate, metallic magnesium and charcoal, with some 
 resinous material. The priming consists of black powder and 
 metallic magnesium. 
 
 When the oil rushes out of the jet, it forces up the plunger 
 of a friction lighter and ignites this core of fiercely burning 
 mixture. 
 
INCENDIARY MATERIALS 
 
 351 
 
 The range of these small projectors is from 14 to 17 meters 
 (17 to 20 yards) but the duration of the flame is rather less 
 than a minute. 
 
 In a later pattern, it was designed that one nozzle should 
 be issued to three reservoirs. After the discharge of one, the 
 jet is attached to the others in succession. This is called the 
 *'Wx" Flammenwerfer (interchangeable). In this way a 
 squad of three men could carry 58 pints of inflammable oil. 
 It is a question, though, whether the third man would live 
 to use his reservoir. 
 
 6age 
 
 "^.i. I 
 
 *♦ 
 
 Htjdroqe 
 
 hkjdro^en Ignition ; >- '' , 
 
 Fig. 115. — Boyd Flame Projector. 
 
 The fact that the trenches were often very close together 
 during the early part of the war, made possible the use of 
 large or stationary Flammenwerfer. These consisted of a steel 
 reservoir SVg feet in height and l^/g feet in diameter, weighing 
 about 250 pounds, which could be connected to two steel 
 cylinders, containing nitrogen under pressure. These carried 
 180 liters (40 gallons) of liquid and operated under a pressure 
 of 15 atmospheres. The discharge nozzle was at the end of 
 a metal tube three feet long, and its orifice was about Vig 
 of an inch in diameter. The range of this apparatus was 
 
352 CHEMICAL WARFARE 
 
 from 33 to 40 yards and the duration of the flame from one 
 to two minutes. Because of the comparatively short range 
 of these guns and the ease with which they could be destroyed, 
 if located by the enemy, their use was very limited. 
 
 Even with the portable flammenwerfer, the most difficult 
 thing to do is to get near enough the target to make the 
 shoot effective. Another serious disadvantage is its very short 
 duration. It is impossible to charge up again on the spot, 
 and the result is that once the flame stops, the whole game 
 is finished and the operators are at the mercy of the enemy. 
 
 With these facts in mind it is easy to see how service 
 in the flaming gun regiments is apparently a form of punish- 
 ment. Men convicted of offenses in other regiments were 
 transferred cither for a time or permanently and were forced 
 under threat of death in the most hazardous enterprises and 
 to carry out the most dangerous work. Taken all in all the 
 flame thrower was one of the greatest failures among the many 
 promising devices tried out on a large scale in the war. 
 
chaptp:r XXI 
 
 THE PHARMACOLOGY OF WAR GASES 
 
 The pharmacology of war gases plays such an important 
 part in chemical warfare that a brief discussion may well be 
 given of the methods used in the testing of gases for toxicity 
 and other pharmacological properties. 
 
 War gases may be divided into two groups: persistent and 
 non-persistent, each of which may include several classes: 
 
 I. Lethal 
 
 II. Lachrymatory 
 
 III. Sternutatory 
 
 IV. Special 
 
 PJach class necessitates special tests in order to determine 
 whether or not it is suitable for further development. 
 
 , Toxicity 
 
 One of the first paints which must be carefully determined 
 in investigating a substance is its toxicity. It is important 
 that this be determined for numerous reasons: 
 
 1. To determine what concentrations are dangerous in the 
 field. 
 
 2. To ascertain how effective protective devices have to 
 be to furnish sufficient protection against the gas. 
 
 3. To furnish a basis for accurate experimental work on tlid 
 treatment of gassed cases. 
 
 4. To decide whether or not the material is worthy of further 
 development in the laboratory or in the plant. 
 
 These considerations necessitate the determination of the 
 toxicity in the form of a vapor and not by the ordinary method 
 of administration by mouth, through the skin (subcutaneously) 
 or through the blood (intravenously). The simplest method of 
 determining the toxicity of a substance as a vapor would be 
 to place animals in a gas-tight box and introduce a known 
 amount of the substance in the form of vapor. But by this 
 
 353 
 
354 
 
 CHEMICAL WARFARE 
 
 method the concentration is not accurately known unless chemical 
 analyses of the air are made, and then it is found to be much 
 less than that calculated from the amount of substance intro- 
 duced, because of condensation on the walls of the chamber, or 
 absorption of the substance by the skin and hair of the animal 
 and in some cases, of decomposition of the substance by moisture 
 in the air. Moreover, it is found that the concentration decreases 
 markedly with time. Because of these factors, the figures used 
 for the concentration are more or less guess work. To overcome 
 these difficulties, a chamber is used through which a continuous 
 current of air, containing a known and constant amount of the 
 
 k€> 
 
 Fig. 116. — Continuous Flow Gassing Chamber for Animals. 
 
 poisonous vapor, is passed. Such an apparatus is shown in 
 Fig. 116. 
 
 The flask ^ is a 300 cc. Erlenmeyer flask, with a ground glass 
 stopper. The liquid to be tested is placed in this flask together 
 with a sufficient quantity of glass wool to prevent splashing and 
 the carrying over mechanically of droplets of the liquid. Air is 
 passed through A and C (calcium chloride drying tubes) and 
 the rate measured by the flow meter D. The air and gas are 
 mixed in F before passing into the chamber G. This chamber is 
 made of plate glass, is of about 100 liters capacity, and is air- 
 tight. The entire flow of air and gas through the box, kept 
 constant at 250 liters per minute, is measured at H. The gas is 
 removed through K, which is filled with charcoal and soda lime, 
 in order that little gas may pass into the pump. 
 
 By weighing the flask E, and its contents before and after 
 passing air through it, and knowing the total volume of the 
 
THE PHARMACOLOGY OF WAR GASES 355 
 
 mixture passing through the chamber during the same period, 
 the concentration of the substance can readily be calculated. 
 This concentration, as determined by the "loss in weight" 
 method, can be checked by chemical analysis (samples taken at 
 M — M). The method has been found to give accurate values. 
 
 The concentration in the chamber reaches its constant level 
 within 30 to 40 seconds after the apparatus is started. 
 
 With the flow of 250 liters per minute, the difficulties men- 
 tioned above are reduced to a point where they are practically 
 negligible. 
 
 All toxicity tests on mice were made with an exposure of ten 
 minutes, while dogs were exposed for thirty minutes. In case 
 death did not occur during exposure, the animals were kept 
 under observation for several days. Toxicity and all other 
 figures are expressed in milligrams per liter of air, though parts 
 per million (p.p.m.) was frequently used during the early 
 work. 
 
 Another point of difficulty is the great individual variation 
 in the susceptibility of animals. This is probably greater than 
 when the poison is administered subcutaneously or intravenously. 
 It necessitates the use of a large number of animals in making a 
 determination of the toxicity of a gas. Again, the toxicity for 
 different species may vary, and as the ultimate aim is a knowl- 
 edge of the toxicity for man, a great many different species must 
 be used. If the toxicity is widely different for different animal 
 species, it is hard to arrive at a definite conclusion as to the 
 toxicity for man. 
 
 With longer exposures than thirty minutes the lethal con- 
 centration is usually less, there being a cumulative effect. This 
 is not true for hydrocyanic acid. If the concentration is not 
 enough to kill at once, an animal can stand it almost indefinitely. 
 Whether the action is cumulative or not depends on the rate at 
 which the system destroys or eliminates the poison. If the 
 poison is being eliminated as fast as received the concentration 
 in the tissues cannot increase. It is stated, for example, that 
 the amount of nicotine in a cigar would kill a man if taken in 
 one dose. If it is spread over twenty minutes, the destruction or 
 elimination of the nicotine is so rapid that no obviously bad 
 effects are noted. 
 
 Another interesting thing about the work on poison gases is 
 
!53 
 
 CHEMICAL WARFARE 
 
 that in most cases a preliminary exposure to less than the lethal 
 concentidtion does not seem to make the animal either more or 
 less sensitive on a later exposure. This is quite unexpected, be- 
 cause we know that with irritating gases, especially lachrymators, 
 men adapt themselves to much higher concentrations than they 
 could stand at first. In view of the experiences of arsenic 
 eaters, it is quite possible that the experiments, which showed no 
 accustoming to toxic gases, were not continued long enough to 
 give positive results. 
 
 Not only does the susceptibility of different animals of the 
 
 Air Intake 
 
 Dry Filtered ^ir 
 under Pressure 
 
 f°SF 
 
 l/m 
 
 ELEVATION 
 Aeration Apparatus jj J 
 
 Not drawn to Scale 
 
 HI 
 
 ^F 
 
 Fig. 117. 
 
 Bg PLAN DF E 
 -Aeration Apparatus for Testing Lachrymators. 
 
 same species vary greatly for a particular gas, but the suscep- 
 tibility of different species varies greatly with different gases. 
 Thus while the effects of certain gases on mice are quite com- 
 parable to the effects on man, it is very far from being true with 
 other gases. 
 
 Lachrymators 
 
 While one cannot determine the lethal concentrations of 
 poison gases for men, it is possible to determine the concentration 
 that will produce lachrymation. The threshold value is that at 
 which two-thirds of the observers experience irritation. The 
 lachrymatory value is considerably higher than the threshold 
 value. 
 
 A very satisfactory method for determining lachrymatory 
 values is shown in Fig. 117. Air is measured at A and 
 bubbled through the lachrymatory substance in B. The air and 
 
THE PHARMACOLOGY OF WAR GASES 
 
 357 
 
 gas are mixed in D and pass into E, a gas-tight, glass-walled 
 chamber of about 150 liters capacity. The gas is removed 
 through Ef, by suction and the volume of the air-gas mixture 
 measured by the flow meter, F. 
 
 After the apparatus has run a few minutes, and the con- 
 centration of the gas has become constant, the subject is 
 instructed to adjust the mask, attached at H, and to tell what- 
 
 M: 
 
 Air Pressure 
 
 FRENCH SPRAY 
 
 Not to Scale 
 
 Approz.FulI Size 
 
 SIDE ELEVATION 
 Not to Scale 
 
 END ELEVATION 
 
 Approx.Full Size 
 
 Fig. 118.— Type of Spray Nozzles. 
 
 ever he notices just as soon as he notices it. The operator 
 stands in such a position that he can manipulate the stopcock H 
 without being observed by the subject. After breathing air for 
 a time (il is a two-way cock, connected with the air through J, 
 and to the chamber through Eg) both to become accustomed 
 to the mask and to eliminate, as far as possible, any "psycho- 
 logical symptoms," the subject is allowed to breathe the gas 
 mixture for a maximum of three minutes. If the expected symp- 
 toms are produced in less than this time, the test is discontinued 
 as soon as they develop. 
 
358 CHEMICAL WARFARE 
 
 For accurate work, it is necessary to work with a pure sample 
 which is at least fairly volatile. Mixtures cannot be run by this 
 method. In this case it is necessary to volatilize each separately, 
 passing the vapors simultaneously into the mixing chamber E. 
 
 A spray method may also be used with satisfactory results. 
 Types of sprays are shown in Fig. 118. 
 
 Odors 
 
 Because of the great value in detecting low concentrations 
 of gases in the field, it is important to know the smallest amount 
 of a gas that can be detected by odor. In some cases, this test is 
 more delicate than any chemical test yet devised. 
 
 Odors may be divided into two classes, true odors, and mild 
 irritation. By true odor is meant a definite stimulation of the 
 olfactory nerve, giving rise to a sensation which is more or less 
 characteristic for each substance producing the stimulation. 
 Mild irritation defines the sensation which is confused with the 
 sense of smell by untrained observers, but which is really a gentle 
 stimulation of the sensory nerve endings of the nose. This so- 
 called odor of substances producing this effect is not character- 
 istic. Higher concentrations of these compounds almost in- 
 variably cause a definite irritation of the nose. 
 
 Examples of true odors are the mercaptans, mustard gas, 
 bromoacetone, acrolein, chlorine and ammonia. Substances 
 which cause mild irritation are chloroacetone, methyl dichloro- 
 arsine, ethyl iodoacetate and chloropicrin. 
 
 In making the test for odor, the same apparatus is used as for 
 lachrymators. The time of exposure is shortened to 30 seconds, 
 as the subject always detects the odor at the first or second in- 
 halation. 
 
 In this connection the recent work of Allison and Katz (J. 
 Ind. Eng.'Chem. 11, 336, (1919)) is of interest. They have de- 
 signed an instrument, **the odorometer, ' * for measuring the in- 
 tensity of odors in varying concentrations in air. It is based on 
 the principle given above. A measured volume of air is passed 
 through the liquid and then diluted to a given concentration. 
 The mixture is then passed through a rubber tube with a glass 
 funnel at the open end. Only one inhalation of the mixture is 
 
THE PHARMACOLOGY OF WAR GASES 359 
 
 used to determine the intensity of the odor. The position of any 
 strength of odor on the scale depends upon the sensitiveness and 
 judgment of the operator, but with one person conducting the 
 entire test, the results have been found quite satisfactory. (See 
 tables on pages 360 and 361.) 
 
 Skin Irritants 
 
 Substances which seem useful for producing skin burns are 
 studied both on animals and on man. Dichloroethyl sulfide 
 (mustard gas) is used as a basis of comparison. Several methods 
 are available. 
 
 Direct Application. This method consists of the direct 
 application of the compound itself to the skin, using a definite 
 quantity (0.005 cc. or 0.005 mg.) over a definite area (5 square 
 centimeters) of the skin. With such a quantity of mustard gas 
 a rather severe burn on animals is produced. No precautions 
 are taken to prevent evaporation from the skin since it is 
 believed that in this way the test will approximate fairly closely 
 the field conditions. 
 
 Vapor Tests. Preliminary tests with vapors of volatile 
 compounds are best made by placing a small amount of the 
 material on a plug of cotton in the bottom of a test tube enclosed 
 in a larger test tube which acts as an air jacket. After about an 
 hour at room temperature the mouth of the test tube is applied 
 to the skin. The concentration is not known, but one is dealing 
 practically with saturated vapor. If an exposure of from 30 to 
 60 minutes produces no effect, one is safe to assume that the 
 compound is not sufficiently active to be of value as a skin 
 irritant. 
 
 If quantitative results are desired, the apparatus shown in 
 Fig. 119 is used. Dry air is blown through the bubbler, which 
 is connected with a series of glass skin applicators. ' The con- 
 centration is determined in the usual way. The skin applicator 
 consists of a small cylinder about 1.5 to 2 cm. in diameter and 
 about 4 cm. long with a small glass handle attached on top. 
 The opening is 1 cm. in diameter. "When the concentration of 
 the gas is constant, the exposure to the skin is made directly 
 for ^ny desired length of time. The skin irritant efficiency is 
 
360 
 
 CHEMICAL WARFARE 
 
 
 
 
 
 
 
 
 
 
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THE PHARMACOLOGY OF WAR GASES 
 
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362 
 
 CHEMICAL WARFARE 
 
 judged by comparing the per cent of positive responses to 
 approximately equal concentrations of the vapors, using mus- 
 tard gas as a standard. 
 
 Touch Method. This method consists of dipping a small 
 glass rod drawn to a needle-like end to the depth of 1 mm. 
 
 Ait Pressure 
 
 A To be Corked when 
 
 not in use. 
 
 Applied to Skin when 
 
 iu use. 
 
 Absorption 
 for Analysis 
 
 Fig. 119. — Skin Irritant Vapor Apparatus. 
 
 in the compound and then quickly touching the skin. The 
 method is qualitative only. 
 
 Use of Solutions. Alcohol, kerosene, olive oil, carbon 
 tetrachloride and other solvents may be used for the purpose of 
 determining the lowest effective concentration of a substance, 
 and for the determination of the relative skin irritant efficiencies 
 of various compounds. Since the skin irritants were scarcely 
 ever used in this form in the field, that is, in solution, the 
 method is not as satisfactory as the vapor method. 
 
CHAPTER XXII 
 
 CHEMICAL WARFARE IN RELATION TO STRATEGY 
 AND TACTICS ^ 
 
 Fundamentals of War. The underlying fundamental prin- 
 ciples of Chemical Warfare are the same as for all other arms. 
 P)ecause of this, it is worth while, and even necessary, to under- 
 stand the applications of Chemical Warfare, for us to go back 
 and study the work of the masters in war from the dawn of 
 history down to the present. When we do that we find that 
 the underlying fundamental principles of war remain un- 
 changed. They are the same to-day as they were in the time 
 of Demosthenes, and as they will be 10,000 years from now. 
 It is an axiom that th e basis of success in wa r is ihp. flbility to 
 have at the decisive point at th e decisive m om^ut-a^ more 
 effective force than that of the enemy. This involves men 
 and materials. It involves courage, fight ing_abilit y^ and t he 
 discrimination and energy of the opposing command ers. 
 
 A nother fundamental is that no success is achieved wit hout 
 positive action ; passive rpsistflTipp npy^^f wins These are really 
 unchanging fundamentals. We may also say that the vigor of 
 attack, the speed of movement of men and supplies, and the 
 thorough training of men in the use of the weapons of war 
 are unchanging requirements, but outside of these everything 
 is subject to the universal law of change. 
 
 Grecian Phalanx and Roman Legion. The last word in the 
 development of human strength as a battle weapon was illus- 
 trated by the Grecian phalanx with its sixteen rows of men, 
 the spears of each row being so adjusted that all reached to 
 the front line. That phalanx could not be stopped by any other 
 
 * This material is adapted from a lecture by Gen. Fried before the 
 students of the General Staff College, in Washington, May 11, 1921. 
 
 363 
 
364 CHEMICAL WARFARE 
 
 human formation that met it face to face. To overcome it 
 required a Roman legion that could open up and take the 
 phalanx in the flank and rear. In the same way, the elephants 
 of the Africans and the chariots of the Romans with their great 
 swords swept all in front of them, until the Roman Legion, 
 opening up into smaller groups allowed the elephants and 
 chariots to pass through only to close in on them from the rear. 
 Then and then only did those engines of war disappear forever. 
 
 Frederick the Great. Frederick the Great, realizing that 
 rapidity of fire would win on the fields of battle where he 
 fought, trained his men to a precision of movement in close 
 order probably never achieved by any other troops in the world 
 and then added to their efficiency by teaching them to load 
 and fire muskets at double the rate of that of his adver- 
 saries. He was thus enabled to concentrate at the decisive 
 points a preponderance of power, which swept all his enemies 
 before him. 
 
 Napoleon. Napoleon achieved the same decisive power in 
 a different way. Realizing that his French troops could not 
 stand the rigorous training that the Prussians underwent, he 
 trained them to fight with great enthusiasm, to travel long dis- 
 tances with unheard-of swiftness, and to strike the enemy 
 where least expected. He added to that a concentration of 
 artillery until then not thought of as possible on the field of 
 battle. He, of course, had also a genius for organizing and 
 keeping up his supply. 
 
 Grant and Jackson. Grant at Vicksburg and Stonewall 
 Jackson in the Shenandoah Valley and at Chancellorsville, 
 achieved the same results in different ways. In every case the 
 fundamental principle of concentrating the greatest force at 
 the decisive point at the vital moment in the battle remained 
 the same. The methods for achieving that end change with 
 every age, and every commander of world-wide renown de- 
 veloped something new or used an old method in a new way. 
 And that is the fundamental requirement for a successful gen- 
 eral. Hannibal, Hasdrubal, Caesar, Napoleon, Frederick the 
 Great, Scott, Grant, and Jackson were all independent thinkers. 
 Each and every one dared to do something that every other 
 general and statesman of his time told him could not be done 
 
RELATION TO STRATEGY AND TACTICS 365 
 
 or that would bring about disaster. They had the courage of 
 their convictions. They had the courage to think out new 
 ideas and to develop them, and then they had the courage to 
 carry through those convictions, not alone against the opposi- 
 tion of the enemy, but against the opposition of their own 
 people, both in the field and at home. And we may be per- 
 fectly sure that in each case had these men not done the things 
 they did, they would have gone down to oblivion just as has 
 been the case with millions of others who tried the usual 
 methods in the usual way. 
 
 Chemical Warfare Latest Development. Chemical Warfare 
 is the latest development of war. So far as the United States 
 is concerned, it is considerably less than four years old. It is 
 the most scientific of all methods of fighting and also the most 
 universally applicable to all other methods of making war. Theli 
 use of poisonous and irritating gases in war is just as funda- ! 
 mental as the introduction of gunpowder. In fact, they have 
 
 '} 
 
 an even wider application to war than powder itself. 
 
 Necessity for New Methods. The idea that has been eSlj 
 pressed above is that the General Staff and the Army com-n 
 mander who sticks to old and tried methods and who is unwill- 
 ing to try with all his might new developments, will never | 
 achieve any first-class success. The General Staffs and thej 
 generals of the future that win wars will be the ones who 
 make the most vigorous and efficient use of Chemical Warfare 
 materials. They cannot confine this use to the artillery, to 
 Aviation, to Special Gas Troops, or to any other single branch 
 of the war machine. They must make use of it in every way. 
 
 What Is Meant by Gas. It must be understood that by 
 gases we refer to materials that injure by being carried to the 
 victim in the air. The word ''gas" has nothing whatever to 
 do with the condition of the material when in the shell, or the 
 bombs, or the cylinders before released. In every case, the 
 gases are liquids or solids. When the containers are broken 
 open the liquids are volatilized either by the gas pressure or by 
 the force of the explosion of the bomb. 
 
 Groups of Gases. Chemical Warfare gases are divided into 
 three great gi^oups. So far as their actual tactical use on the 
 field of battle is concerned, there are only two groups — per- 
 
366 CHEMICAL WARFARE 
 
 sistent and non-persistent. The third is the irritant group. 
 This group affects the eyes and the lungs so as to make the 
 victim very uncomfortable if not completely incapable of action 
 in quantities so small as to cause no injury that lasts more than 
 a few hours. The quantities of such gases needed to force the 
 wearing of the mask is ^Aooo that needed to cause the same 
 discomfort by the really poisonous gases, such as phosgene. 
 They, therefore, have a very great economic value in harassing 
 the enemy by forcing him to wear masks and to take other 
 precautions against gas. And no matter how perfect gas masks 
 and gas-proof clothing become, their long-continued use will 
 cut down physical vigor in an ever-increasing ratio until in 
 two or three days an army may be totally incapacitated. 
 
 Smoke. In Chemical Warfare materials we have another 
 great group which will probably be equal in the future to the 
 three, groups just mentioned. That is common smoke. Smoke 
 has a variety of uses. By the simple term ''smoke" is meant 
 smokes that are not poisonous or irritating. Such smokes offer 
 a perfect screen against enemy vision, whether it is the man, 
 who sights the machine gun, the observer in the lookout sta- 
 tion, the cannoneer or even the aeroplane observer. Every shot 
 through impenetrable smoke is a shot in the dark and has a 
 tenth or even less chance of hitting its mark. Smoke affords 
 a means of decreasing the accuracy of firing, much the same as 
 night decreases it, without the inherent difficulties of night 
 action. 
 
 Peace Strategy. The strategy of successful war involves 
 the strategy of peace. This has been true from the days when 
 David with his sling-shot slew Goliath, down to the present 
 moment. We don't always think of it in connection with war, 
 but back of every successful war has been preparation during 
 peace. It, may have been incidental preparation such as the 
 training of men in fighting Indians, and in creating public 
 sentiment favorable to an independent nation that preceded the 
 Revolutionary War. It may, on the other hand, have been a 
 deeply studied policy such as that of the Germans prior to the 
 World War. They tried and generally quite successfully, to 
 coordinate all peace activities toward the day when a war 
 should come that would decide the future destiny of the Ger- 
 
. RELATION TO STRATEGY AND TACTICS 367 
 
 man Empire, and it was only because of that study in peace 
 that Germany almost single-handed was able to stand out for 
 more than four years against the world. The Allies came near 
 losing that war because they did not appreciate that the 
 strategy of efficient war had to be preceded by the strategy of 
 peace. 
 
 Chemical Warfare an Example. Chemical warfare is a par- 
 ticularly good example of this fact. Prior to the World War 
 WG had acknowledged, and without any misgivings, that Ger- 
 many led the world in chemistry, that it produced most of the 
 dyes in the world, and to a large extent the medicines of the 
 world. We felt that when American needs showed it to be 
 advisable we could take up chemistry and chemical production 
 and soon excel the Germans. We had not reckoned on the sud- 
 denness of war. 
 
 We were just getting ready with chemicals, and that in- 
 cluded powders and high explosives, when the war closed. And 
 yet we had had not only eighteen months' intensive preparation 
 after our own entry into the World War, but also the prepara- 
 tion of great steel institutions and powder factories for nearly 
 three years in manufacturing supplies for the Allies who pre- 
 ceded us in the war. 
 
 Coal Tar. The World War opened the eyes of England, 
 France and Japan as well as the United States. Each of them 
 to-day is struggling to build up a great chemical industry as 
 the very foundation of successful war. Few of us realized 
 prior to the World War that in the black, sticky mess called 
 coal tar from the coking of coal or the manufacture of gas 
 from coal and oil, was stored up most of the high explosives 
 used in war, the majority of the poison gases, a great deal of 
 the medicines of the world, and nearly all the dyes of the world. 
 Tha Germans realized it and in their control over methods 
 of using this material, together with the great commercial 
 plants developed to manufacture it, as well as with the trained 
 personnel that must go with such plants, were enabled, when 
 blockaded on land and sea, to furnish the munitions, the cloth- 
 ing and the food needed for four and one-half years of war. 
 
 Great Chemical Industries. Thus it is that our Government 
 to-day is giving most serious heed to the need of building up 
 
368 CHEMICAL WARFARE 
 
 a great chemical industry in the United States. We have the 
 raw materials. We need only the factories and the trained 
 men that go with them. We need, of course, in addition to 
 the development of the coal tar industry, a production of heavy 
 chemicals such as chlorine, sulfuric acid and the like, all of 
 which, however, are bound together by community interest in 
 peace as well as in war. 
 
 Reserves of Chemists. A part of the strategy of peace is 
 the card-indexing of the manpower of a nation divided into 
 special groups. In one great group must come those who have 
 a knowledge of chemistry and the chemical industries. That 
 must be so worked out that if war should come on a moment's 
 notice, within twenty-four hours thereafter every chemist could 
 be given his job, jobs extending from the firing line to the re- 
 search laboratory. And that is the task of the Chemical War- 
 fare Service. And right here it is .well to know that Congress, 
 among the other features of its Army Reorganization Act of 
 June 4, 1920, provided for a separate Chemical Warfare Ser- 
 viee^with^fehese-pirw^rsi ^ 
 
 Chemical Warfare Powers 
 
 The Chief of the Chemical Warfare Service under the authority of 
 the Secretary of War shall be charged with the investigation, develop- 
 ment, manufacture, or procurement and supply to the Army of all 
 smoke and incendiary materials, all toxic gases, and all gas-defense 
 apphances; the research, design, and experimentation connected with 
 chemical warfare and its material ; and chemical projectile filling plants 
 and proving- grounds; the supervision of the training of the Army 
 in chemical warfare, both offensive and defensive, including the neces- 
 sary schools of instruction; the organization, equipment, training, and 
 operation of special gas troops, and such other duties as the President 
 may from time to time prescribe. 
 
 Why Power Is Needed. These rather broad powers indi- 
 cate that Congress realized the unity of effort that must be 
 made from the research laboratory to the firing line if America 
 was to keep pace with Germany or any other nation in chemical 
 warfare. Some have raised the question as to whether a 
 service should be both supply and combat. Perhaps the best 
 
RELATION TO STRATEGY AND TACTICS 369 
 
 answer to that question is that so organized Chemical Warfare 
 was a success in the World War. It was a success notwith- 
 standing- it had to be developed in the field six months after 
 our entry into the war and with no precedents, no materials, 
 no literature and no personnel. Through its officers on the 
 staffs of commanding generals of armies, corps and divisions, 
 and through its fighting gas troops in the front line, it was 
 enabled to direct its research, development and manufacture 
 more quickly along lines shown to be necessary by every change 
 in battle conditions, than any other service. 
 
 Chemical Warfare Troops. And why should there not be 
 fighting Chemical Warfare troops? They fight under exactly 
 the same orders as all other troops. They conform to the same 
 general plan of battle. They bring, however, to that battle 
 experts in a line that it takes a long time to master. And where 
 has there been any live commander in the world's history who 
 refused aid from any class of troops that might help him win? 
 
 Specialists in War. The wars of the future will become 
 more and more wars of the specialists. Your Infantry may 
 remain the backbone of the fighting force, but if it has not the 
 Artillery, the AA^iation, the Chemical Warfare, the Engineers, 
 the tanks and other specialists to back it up, it will be over- 
 come by the army which has such specialists. Indeed the 
 specialist goes into the very organization of the Infantry itself 
 with its machine gun battalions, its tank battalions, and as now 
 proposed, the Infantry light howitzer companies. 
 
 Duties of Chemical Warfare Staff Officers. The Chemical 
 Warfare officers on the staff of armies, corps and divisions are 
 there for the purpose of giving expert advice as to the quan- 
 tities of chemical materials available, the best conditions for 
 using them, and the best way of avoiding the effects of enemy 
 gas upon our own troops. The conditions that must be kept in 
 mind are so many that no other officer can be expected to master 
 and keep them if he does his own work well. The general 
 staff officers and commanding generals will not have the time 
 to even try to remember the actual effects of clouds, wind, rain, 
 trees, valleys, villages and plains upon each and every gas. 
 They must depend upon the Chemical Warfare officer for accu- 
 rate information along those lines, and if he cannot furnish it 
 
370 CHEMICAL WARFARE 
 
 they will have to secure some one who can. The history of 
 war is filled with the names of generals who failed because 
 they conld not forget how to command a company. These 
 Chemical Warfare officers will also furnish all data as to supply 
 of chemical warfare materials, and will furnish the best infor- 
 mation along lines of training, whether for defensive or offen- 
 sive use of gas. 
 
 Gras Used by all Arms. As before stated, we cannot confine 
 the use of gas to any one arm. We may then ask why, if it 
 is applicable to all arms, it should need special gas troops. 
 Special gas troops are for the purpose of putting off great 
 quantities of chemical warfare materials by special methods 
 that are not applicable to any other branch now organized 
 or that any other branch has the time to master. Long-range 
 firing of gas by the artillery can be done just as well by the 
 artillery as by gas troops. Why? Because in the mechanics 
 of firing chemical ammunition there is no difference whatever 
 from the mechanics of firing high explosives or shrapnel. The 
 same will be true of gas rifle grenades and smoke candles in 
 use by the Infantry. The same will be true of the dropping 
 of gas bombs and the sprinkling of gas by the aeroplanes. In 
 this connection just remember that all of the army is trained 
 in first aid, but in addition we have our ambulance companies, 
 our hospitals, and our trained medical personnel. 
 
 Arguments Against Use of G-as. It has been many times 
 suggested since the Armistice that the use of poisonous gas in 
 Vv^ar may be done away with by agreement among nations. 
 TJie arguments against the use of gas are that itjs_inhiiinane 
 and that it might b-e_ used against non-CQmbatant,Sj__especially 
 women and diildren. The inhumanity of it is absg]ut_ely dis- 
 proven by the results of its use in the AVorld War. The death 
 rate from gas alone was less than one-twelfth that from bullets, 
 high explosives and other methods of warfare. The disability 
 rate for gas patients discharged was only about one-fourth 
 that for the wounded discharged for other causes. The per- 
 manently injured is likewise apparently very much less than 
 from other causes. 
 «^ Humanity. No reliable statistics that we cf n get show that 
 gas in any way causes tuberculosis any more than a severe 
 
RELATION TO STRATEGY AND TACTICS 371 
 
 attack of bronchitis or pneumonia causes tuberculosis. Since 
 its principal effects are upon the lungs and, therefore, hidden 
 from sight, every impostor is beginning to claim gassing as the 
 I'cason for his wanting War Risk benefits from the Govern- 
 ment. We do not claim there may not be some who are suf- 
 fering permanent injuries from gas, and we are trying very 
 liard to find out from the manufacturers of poisonous gases 
 and allied chemicals if they have any authentic records of such 
 cases. So far the results indicate that permanent after-effects 
 are very rare. 
 
 As to non- combatants, certainly we do not contemplat e 
 using poisonous gas against them , nQ _more at least than w e 
 propo se to use high explosives in long range guns or aeroplanes 
 against them. The use of the one against non-combatants is 
 just as damnable as the other and it is just as easy^.to refrain 
 fi'ora._ using one as the other. 
 
 Gas Cannot be Abolished. As to the abandonment of poison 9^ 
 gas, it must be remembered that no powerful weapon of war 
 lias ever been abandoned once it proved its power unless a 
 more powerful weapon was discovered. Poisonous gas in the 
 World War proved to be one of the most powerful of all 
 weapons of war. For that reason alone it will never be aban- 
 doned. It cannot be stopped by agreement, because if you 
 can stop the use of any one powerful weapon of war by agree- 
 ment you can stop all war by agreement. To prepare to use 
 it only in case it is used against you is on the same plane as 
 an order that was once upon a time issued to troops in the 
 Philippine Islands. That order stated in substance that no 
 officer or soldier should shoot a savage Moro, even were he 
 approaching the said officer or soldier with drawn kriss 
 (sword), unless actually first struck by such savage. Every 
 officer preferred, if necessary, to face a court-martial for dis- 
 obedience of such an order rather than allow a savage Moro 
 with a drawn kriss to get anywhere near, let alone wait until 
 a^'tually struck. 
 
 Let the world know that we propose to use gas against 
 alljtroops that may be engaged against_us^ and that we pro- 
 l)ose to use it to the fullest extent oijiur_aMlity. We believe 
 that such a proposition will do more to head off vjrar than all 
 
372 CHEMICAL WARFARE 
 
 the peace propaganda since time began. It has been said that 
 we should not use gas against those not equipped with gas. 
 Then why did we- use repeating rifles and machine guns against 
 Negritos and Moros armed only with bows and arrows or poor 
 1 muskets and knives. Let us apply the same common sense to 
 ^ the use of gas that we apply to all other weapons of waf.J 
 
 Effect on World War Tactics. A very brief study of the 
 effects of chemical warfare materials on the strategy of the 
 World War will indicate its future. It began with clouds of 
 chlorine let loose from heavy cylinders buried under the firing 
 trench. These took a long time to install and then a wait, 
 sometimes long, sometimes brief, for a favorable wind, but even 
 at that these cloud gas attacks created a new method of fight- 
 ing and forced new methods of protection. Gas at once added 
 a tremendous burden to supply in the field, to manufacture, 
 and to transportation, and in a short time even made some de- 
 cided changes in the tactics of the battle field itself. 
 
 Cloud Gas. The fact that the gas cloud looked like smoke 
 is responsible for the name ' ' cloud gas. ' ' Really all gases are 
 nearly or wholly invisible, but those which volatilize suddenly 
 from the liquid state so cool the air as to cause clouds of con- 
 densed water vapor. The cloud obscured everything behind 
 and in front of it. It led the German to put off fake smoke 
 clouds and attack through them, thus taking the British at a 
 tremendous disadvantage. Then and there began a realization 
 of the value of smoke. Cloud gas was also the real cause of 
 the highly organized raid that became common in every army 
 during the World War. The real purpose in the first raids, 
 carried out by means of the box barrage, was to find out 
 whether or not gas cylinders were being installed in trenches. 
 
 These raids finally became responsible, in a large measure, 
 for driving the old cloud gas off the field of battle. It did not, 
 however, stop the British from putting off cloud gas attacks in 
 1918 by installing their gas cylinders on their light railway 
 cars and then letting the gas loose from the cylinders while 
 still on the cars. This enabled them to move their materials 
 to the front and put off gas attacks on a few hours' notice 
 when the wind was right. 
 
 Toxic Smoke Candles. To-day we have poisonous smokes 
 
RELATION TO STRATEGY AND TACTICS 373 
 
 that exist in solid form and that are perfectly safe to handle 
 until a fuse is lighted. The so-called candles will be light 
 enough so that one man can carry them. With these, cloud 
 gas can be put off on an hour 's notice when wind and weather 
 conditions are right, no matter how fast the army may be 
 moving and whether on the advance or in retreat. Cloud gas 
 will usually be put off at night because the cloud cannot be 
 seen, because then men are tired and sleepy, and all but the 
 most highly trained become panicky. Under those conditions 
 the greatest casualties result. The steadiness of wind currents 
 also aids cloud gas attacks at night. 
 
 Value of Training in Peace. And this brings up the value 
 of training in peace. We are frequently asked, *'Why do you 
 need training with masks in peace ; why do you need training 
 with actual gas in peace ; cannot these things be taught on short 
 notice in war ? ' ' The answer is, " No ! * ' Nothing will take the 
 place of training in peace. 
 
 All of us recall that early in the war the Germans spread 
 broadcast charges that the Allies were using unfair and inhu- 
 mane methods of fighting because they brought the Ghurka 
 with his terrible knife from Asia and the Moroccan from Africa. 
 And we all know that after a time the Germans ceased saying 
 anything about these troops. What was the cause ? They were 
 not efficient. Just as the Negro will follow a white officer over 
 tlie top in daylight and fight with as much energy and courage 
 and many times as much efficiency as the white man, he cannot 
 stand the terrors of the night, and the same was true of the 
 Ghurka and the Moroccan. 
 
 All the Allies soon recognized that fact as shown by their 
 drawing those troops almost entirely away from the fighting 
 lines. In some cases dark-skinned troops were kept only as 
 shock troops to be replaced by the more highly developed Cau- 
 casian when the line had to be held for days under the deadly 
 fire of the counter attack. The German idea, and our own 
 idea prior to the World War, was that semi-savages could 
 stand the rigors and terrors of war better than the highly sen- 
 sitive white man. War proved that to be utterly false. 
 
 Familiarity with Gas Necessary. The same training that 
 makes for advancement in science, and success in manufacture 
 
374 CHEMICAL WARFARE 
 
 in peace, gives the control of the body that holds the white 
 man to the firing line no matter what its terrors. A great deal 
 of this comes because the white man has had trained out of 
 him nearly all superstition. He has had drilled into him for 
 hundreds of years that powder and high explosive can do cer- 
 tain things and no more. If the soldier is not to be afraid of 
 gas we must give him an equal knowledge of it, its dangers, 
 and its limitations. The old adage says, ''Familiarity breeds 
 contempt." Perhaps that is not quite true, but we all know 
 that it breeds callousness and f orgetfulness ; that the man man- 
 ufacturing dynamite or other more dangerous explosives takes 
 chances that we who do not engage in such manufacture 
 shudder at. 
 A- Ed^ewood Chemists Not Afraid. All of this has direct 
 application to training with chemical warfare materials in 
 peace. We helieve that all opposition to chemical warfare to-day 
 can he divided into two classes — those who do not understand 
 it and those who are afraid of it — ignorance and cowardice. 
 Our chemists at Edgewood Arsenal are every day toying with 
 the most powerful chemical compounds; toying with mixtures 
 they know nothing of, not knowing what instant they may 
 induce an explosion of some fearful poisonous gas. But they 
 have learned how to protect themselves. They have learned 
 that if they stop breathing and get out of that place and on 
 the windward side they are safe. They have been at that work 
 long enough to do that automatically. 
 ^ Staff Officers Must Think of Gas in Every Problem. The 
 staff officer must train the army man in peace with all chemical 
 ^\\U^^ warfare materials or he will lose his head in war and become 
 ffiP^ a casualty. The general staff officers aild commanding generals 
 jA must so familiarize themselves with these gases and their gen- 
 eral use that they will think them in all their problems just 
 exactly as they think of the Infantry, or of the Cavalry, or 
 of the tanks or of the Artillery in every problem. On them 
 rests the responsibility that these gases are used properly in 
 battle. If plans before the battle do not include these materials 
 for every arm and in the proper quantities of the proper kinds 
 they will not be used properly on the field of battle and on 
 them will rest the responsibility. 
 
RELATION TO STRATEGY AND TACTICS 375 
 
 They are not expected to know all the details of gases and 
 their uses, but they will be expected to consider the use of gas 
 in every phase of preparing plans and orders and then to 
 appeal to the chemical warfare officers for the details that 
 will enable them to use the proper gases and the proper quan- 
 tities. They cannot go into those details any more than they 
 can go into tlie details of each company of infantry. If they 
 try to do that tliey are a failure as staff officers. 
 
 Effect of Masks on Troops. The very best of masks cause ^ 
 a little decrease in vision, a little increase in breathing resist- 
 ance, and a little added discomfort in warm weather, and hence 
 the soldier must learn to use them under all conditions. But 
 above all in the future he must be so accustomed to the use 
 of the mask that he will put it on automatically — almost in 
 his sleep as it were. We have tear gases, to-day, so powerful 
 and so sudden in their action that it is doubtful if one man 
 out of five who has had only a little training can get his mask 
 on if subject to the tear gas alone — that is, with tear gas 
 striking him with full force before he is aware of it. 
 
 Effectiveness of Gas in World War. In the past war more 
 than 27 out of every 100 Americans killed and wounded suf- 
 fered from gas alone. You may say that many of the wounds 
 were light. That is true ; but those men were put out of the 
 battle line for from one to four months — divisions, corps and 
 armies almost broken up — and yet the use of gas in that war 
 was a child's game compared to what it will be in the future. 
 
 It is even said that many of them were malingerers. Per- 
 haps they were, but do you not suppose that there were at least 
 as many malingerers among tjie enemy as there were in our 
 own ranks? Furthermore, if you can induce malingering it 
 is a proper method of waging war, and unless our tToasted 
 ability is all a myth we should have fewer malingerers under 
 conditions of battle than any other nation. 
 
 Strategy of Gas at Picardy Plains. Let us go back nowHo 
 the strategy of gas in war. Following the cloud gas came tear 
 gases and poisonous gases in shells and bombs. A little advance 
 in tactics here and a little there, the idea, though, in the early 
 days being only to produce casualties. As usual the Germans 
 awoke first to the fact that gas might be used strategically and 
 
376 CHEMICAL WARFARE 
 
 on a large scale. And thus we find that ten days before he began 
 the battle of Picardy Plains he deluged many. sections of the 
 front with mustard gas. He secured casualties by the thousands, 
 but he secured something of greater importance. He wore out 
 the physical vigor and lowered the morale of division after 
 division, thus paving the way for the break in the British 
 Army which almost let him through to the sea. 
 
 He used non-persistent gases up to the very moment when 
 his own men reached the British lines, thereby reducing the 
 efficiency of British rifle and artillery fire and saving his own 
 ^men. And this is just a guide to the future. A recent writer 
 in the Field Artillery Journal states that gas will probably not 
 be used in the barrage because of its probable interference with 
 the movement of our own troops. In making that statement 
 he forgot the enemy and you cannot do that if you expect to 
 win a war. 
 
 Gas in Barrages. In the future we must expect the enemy 
 to be in a measure as well prepared in chemical warfare as we 
 are. Let us consider the special case of our own men advanc- 
 ing to the attack behind a rolling barrage. "We will consider 
 also that the wind is blowing toward our own troops. Obviously 
 under those conditions the wind will blow our own gas back 
 onto our troops. Will we use gas in that barrage? We cer- 
 tainly will ! Because with the wind blowing toward our own 
 troops we have the exact ideal condition that the enemy wants 
 for his use of gas. He will then be deluging our advancing 
 troops with all the gas he can fire, in addition to high explo- 
 sives and shrapnel. Our men must wear masks and take every 
 precaution against enemy gas. How foolish it would be not to 
 fire gas at the enemy under those conditions. If we did not 
 fire gas we would leave him entirely free from wearing masks, 
 and entirely free from taking every other precaution against 
 gas while our own troops were subject to all the difficulties of 
 gas. No, we will fire gas at him in just as great quantities 
 as we consider efficient. And that is just a sample of what is 
 coming on every field of battle — gas used on both sides by 
 every method of putting it over that can be devised. 
 
 World War Lessons Only Guide Posts. Example of Book 
 Worms. Every lesson taught by the World War must be 
 
RELATION TO STRATEGY AND TACTICS 377 
 
 taken as a guide-post on the road to future success in war. 
 No use of gas or other materials in the past war must be taken 
 as an exact pattern for use in any battle of the future. Too 
 much study, too much attention to the past, may cause that 
 very thing to happen. A certain general commanding a bri- 
 gade in the Argonne told me just recently that while the battle 
 was going on a general staff officer called him on the telephone 
 and asked him what the situation was. He gave it to him. 
 The staff officer then asked, ''What are you doing?" and he 
 told him. The staff officer replied, ''Why, the book doesn't 
 say to do it that way under such conditions. ' ' There you have 
 the absurd side of too much study and too close reliance on 
 details of the past. 
 
 The battle field is a perfect kaleidoscope. The best we can 
 hope to get out of books is a guide — something that we will 
 keep in our minds to help us decide the best way to meet cer- 
 tain situations. He who tries to remember a particular position 
 taught in his school with the idea of applying that to actual 
 use in battle is laying the foundation for absolute failure. Your 
 expert rifleman never thinks back when he goes to fire a shot 
 as to just what his instructor told him or what the book said. 
 He just concentrates his mind on the object to be attained, 
 using so far as comes to him facts he has learned from 
 books or teachers. Your general and your staff must do the 
 same. 
 
 Infantry Use of Gas. A few words about how we will use 
 gas in the future. We will start with the Infantry: The 
 Infantry as such will use gas in only two or three ways. They 
 will use some gas in rifle grenades, and a great deal more smoke. 
 We speak of the rifle grenade because in our opinion the hand 
 grenade is a thing of the past. We do not believe there will 
 ever be used in the future any grenade that is not applicable 
 to the rifle. The Infantry will probably often carry large quan- 
 tities of gas in the shape of the toxic smoke candle. These 
 materials being solids may be shot up by rifles or artillery fire, 
 run over by trucks or tractors, or trampled and still be harm- 
 less. It is only when the fuses are lighted and the material 
 driven off by heat that they are dangerous. In using these 
 candles under these conditions you must have sufficient chem- 
 
378 CHEMICAL WARFARE 
 
 ical warfare officers and soldiers to get the necessary control 
 indicated by the sun, wind, woods, fogs, ravines and the like. 
 
 Cavalry Use of Gas. Next consider the Cavalry. The Cav- 
 alry will use gas practically the same as the Infantry. The 
 chemical warfare troops will accompany the Cavalry with 
 Stokes ' mortars or other materials to fire gases into small enemy 
 strongholds that may be encountered whether machine gun 
 nests, mountain tops, woods or villages. They will do this 
 either against savages or civilized people. Methods of making 
 these materials mobile for that purpose are already well under 
 way. If against savages and one does not want to kill them, 
 use tear gases — ^no better method of searching out hidden 
 snipers in mountain tops, among rocks, or villages, in ravines, 
 or in forests was ever invented. 
 
 Use of Gas by Tanks. The tanks will employ gas in the 
 same way as the Infantry with the possibility, however, that 
 they may be used to carry large quantities of gas on cater- 
 pillar tractors where otherwise it would be difficult to move 
 the gas. This is not a certainty, but is a situation promising 
 enough to warrant further study. 
 
 Artillery Use of Gas. Your Artillery will fire gas and 
 smoke in every caliber of gun. There is a tendency now to 
 limit gas to certain guns and howitzers and to limit smoke to 
 even a smaller number of guns. This is a mistake that we are 
 going to recognize. A very careful study of the records of 
 the war show that more casualties were produced several times 
 over by a thousand gas shells than by a thousand high explo- 
 sive or shrapnel. And that is because gas has an inherent per- 
 manence that no other weapon of war has. 
 
 Permanency of Gas. The bullet whistles through the air 
 and does its work or misses. The high explosive shell bursts, 
 hurling its fragments that in a few seconds settle to earth, 
 and its work is done. The shrapnel acts in the same way, but 
 when one turns loose a shell of gas it will kill and injure the 
 same as the high explosive shell and in the same length of time 
 and in addition for some minutes thereafter. Even with the 
 non-persistent gases, it will continue on its way, causing death 
 or injury to every unprotected animal, man or beast in its 
 
RELATION TO STRATEGY AND TACTICS 379 
 
 path. With the persistent gases, the materials from each shell 
 may persist for days. 
 
 Variety of Uses of Gas. This brings up the point of the 
 great variety of uses to which gas can be put. The non-per- 
 sistent gas may be used at all times where one wants to get 
 rid of it in a few moments — the persistent gas wherever one 
 wants to keep the enemy under gas for days at a time. We 
 will use mustard gas on strong points in the advance, on 
 flanks, on distant areas one will not expect to be reached, 
 and as our own protection of masks and clothing increases 
 toward perfection we will use it on the very fields you expect 
 to cross. Why? Because we will be firing it at the enemy for 
 days before hand and we will cause him trouble all those days 
 v/hile we ourselves will encounter it for a few hours at the 
 most. So do not think that mustard gas is only going to be 
 used in defense in the future. 
 
 Solid Mustard Gas and Long Range Guns. We will come 
 to use chemical warfare materials just as high explosives and 
 bullets are used to-day, even though at times we do suffer an 
 occasional loss from our own weapons. Our Artillery in long 
 range guns where we want destruction will fill each shell with 
 say 15 per cent gas and 85 per cent high explosive. We have 
 a solid mustard gas that may be so used. We have tremen- 
 dously powerful tear gases and irritating gases that may be so 
 used. Being solids they do not affect the ballastic qualities 
 of the shell. And what an added danger will mustard gas from 
 every shell bring against railroad centers, rest villages, can- 
 tonments, cross roads and the like. The results will be too 
 great for any force to overlook such use. 
 
 Tear Gases in Shrapnel. We will probably use tear gas in 
 most, if not all, of our shrapnel. The general idea now is that 
 we should not put tear gas in all shrapnel because under certain 
 conditions it will be blown back and harass our own troops. 
 But as was said before, we must remember that the enemy 
 will be using gas at all times as well as ourselves, and hence 
 if we limit ourselves in any line we give the enemy an advan- 
 tage. This use of gas by the Artillery will extend to all classes 
 of guns — seacoast, field, turret and what not. 
 
380 CHEMICAL WARFARE 
 
 Use of Gas by Air Service. Bombs. Let us next consider 
 the Air Service. We naturally think of dropping gas in bombs 
 v/hen we speak of the use of gas by the Air Service. Gas 
 will so be used and it will be used in bombs of perhaps a 
 thousand pounds or even a ton in weight, at least 50 per 
 cent of which will be gas. Such gases, however, will be of 
 the non-persistent type — phosgene or similar ones. They 
 will be used against concentration camps and cross-roads, 
 on troops on the road in columns; against railroad centers 
 and rest areas; in other words, against groups of men or 
 animals. 
 
 Sprinkling. But that is not even the beginning of the use 
 of gas by aeroplanes. Mustard gas, which is one-third again 
 as heavy as water, and which volatilizes far slower than water, 
 may be sprinkled through a small opening such as a bung hole 
 in a tank that simply lets liquid float out. The speed of the 
 aeroplane will atomize it. In this way, gas can be sprinkled 
 over whole areas that must be crossed in battle. The Lewisite, 
 of which we have heard considerable, will be used. It is less 
 persistent than the mustard gas, but like mustard gas it pro- 
 duces casualties by burning. Unlike mustard gas, however, 
 the burns from a quantity equal to three drops will usually 
 cause death. The material can be made up by hundreds, even 
 thousands, of tons per month. 
 
 We are working on clothing that will keep it out just as 
 we have been and are working on clothing that will protect 
 against mustard gas. But these gases are so powerful that if 
 any opening be left in the clothing the gas will get through, 
 so that even if we get clothing that will protect, it must cover 
 every inch of the skin from head to foot. Besides the mask 
 must be worn at all times. 
 
 Consider the burden put on any army in the field that would 
 liave to continually wear such complete protection. What a 
 strain on the mentality of the men ! As before said, to endure 
 it at all we must train our men to think of such conditions, to 
 face them in peace, and in order to do so we must actually 
 use gas. Just as in the World War the highly trained Cau- 
 casian outdistanced the savage in endurance, just so will the 
 
RELATION TO STRATEGY AND TACTICS 381 
 
 most highly trained men in the future outdistance all others 
 in endurance. 
 
 Navy. We now come to the consideration of the Navy. 
 The Navy will use gas both in its guns and in smoke clouds, 
 and in some form of candle that will float. The toxic smokes 
 that in high enough concentrations will kill are extraordinarily 
 irritating in minute quantities — so minute they cannot be seen 
 or felt for a few moments. Every human being on a ship must 
 breathe every minute just as every human being everywhere 
 must breathe every minute or die. A gas that gets into the 
 ventilating system of a ship will go all through it and the Navy 
 realizes it. 
 
 The Navy is studying how to keep the gas out of their own 
 ships, and how to get it into the enemy's ships. The toxic 
 smokes may be dropped from aeroplanes or turned loose from 
 under water by submarines. In either case they will give off 
 smokes over wide areas through which ships must pass. Any 
 defects will let these toxic smokes in and will force every man 
 to wear a mask. Aeroplane bombs will come raining down on 
 the ship or alongside of it either with toxic smokes or other 
 terrible gases. White phosphorus that burns and cannot be 
 put out wet or dry will be rained on ships. Yes, chemical war- 
 fare materials will be used by the Navy. 
 
 Gas Against Landing Parties. The use of gas against land- 
 ing parties or to aid landing parties has come up in many 
 Vv^ays. Our studies to date indicate that gas is a greater 
 advantage to the defense against landing parties than to the 
 offense. Mustard gas and the like may be sprinkled from aero- 
 planes, and while it will not float long on the water, it will 
 float long enough to smear any small boats attempting to land. 
 It can be sprinkled over all the areas that landing parties must 
 occupy. Mustard gas may be placed in bombs or drums around 
 all areas that are apt to be used as landing places and exploded 
 in the face of advancing troops. 
 
 Storing Reserve Gases in Peace. And a word here about 
 how long gases may be stored. One of the statements made 
 by opponents of chemical warfare was that gas is a purely 
 war time project and could not be stored up in peace. We 
 
382 CHEMICAL WARFARE 
 
 have to-day at Edgewood Arsenal some 1,400 tons of poisonous 
 gases not including chlorine. Those gases have been manu- 
 factured, practically every ounce of them, for three years, and 
 are yet in almost perfect condition. Our chemists believe they 
 can be kept in the future for ten years and perhaps longer. 
 Our gas shells then will have the life almost of a modern battle- 
 ship, while the cost of a million will be but a fraction of the 
 cost of a battleship. What I have just said applies particularly 
 to liquid gases such as phosgene, chlorpicrin, and mustard gas. 
 We know that many of the solids may be kept for far longer 
 periods. 
 
 Storing Gas Masks. Our masks, too, we believe can be kept 
 for at least ten years. Experience to date indicates that rubber 
 deteriorates mainly through the action of sunlight and mois- 
 ture that cause oxidation or other change in the crystalline 
 structure of cured rubber. Accordingly, we are putting up 
 masks to-day in hermetically sealed boxes. It is thus evident 
 that we can store a reserve of masks and gases in peace the ^ 
 same as other war materials. 
 
 Use of Gas by Gas Troops. Now we come to the use of gas 
 by special gas troops. In the war, Gas Troops used 4-inch 
 Stokes ' mortars and 8-inch Livens ' projectors and in a very short 
 time would have used a new portable cylinder for settiiig off 
 cloud gas, using liquid gases, such as phosgene. They will 
 use these same weapons in future wars. All of these are short- 
 range weapons, but since the Livens' bomb or drum contains 
 50 per cent of its weight in gas while the artillery shell con- 
 tains 10 per cent, they have an efficiency away beyond that of 
 artillery or any other method of discharging gas except cloud 
 gas. They will, therefore, produce more casualties than any 
 other method known for the amount of material taken to the 
 front. These short-range weapons were developed by the British 
 for trench use and. not for open warfare, and yet our troops 
 developed methods with the Stokes ' mortars that enabled them 
 to keep up with many of the Infantry divisions. 
 
 Phosphorus and Thermit Against Maxjhine Gun Nests. The 
 use of phosphorus and thermit against German machine gun 
 nests by the Gas Troops is well known. How effective it was 
 
RELATION TO STRATEGY AND TACTICS 383 
 
 not known to so many. Phosphorus and thermit were so 
 'used from the early days of the Marne fight in the latter part 
 of July, 1918, to the very close of the war. There is no recorded 
 instance where the Gas Troops failed to silence machine gun 
 nests once the machine guns were located. In the future Gas 
 Troops will put off the majority of all cloud gas attacks even 
 with toxic smoke candles. 
 
 Necessity for Training in Peace. This is an outline of the 
 subject of chemical warfare. As stated in the beginning, the 
 fundamental underlying principles for the successful use of 
 poisonous gas is necessarily the same as for any other war 
 materials. The necessity for continuous training in peace is 
 just the same with chemical warfare as with the rifle, the 
 machine gun, with field artillery or any other weapon of war. 
 Indeed it is more so because the use of gas is so perfectly 
 adaptable to night work. Men must be taught to take pre- 
 cautionary measures when so sleepy, tired and worn out that 
 tliey will sleep through the roar of artillery. 
 
 How Chemical Warfare Should be Considered. We ask you 
 only to look at the use of chemical warfare materials as you 
 look at the use of the artillery, infantry, cavalry, tanks or aero- 
 planes. Measure its possible future use ; not simply by its use 
 in the World War, but by considering all possible developments 
 of the future. Remember that its use was barely four years 
 old when the war closed, while the machine gun, the latest type 
 of infantry weapon, had been known for more than one-third 
 of a century. Chemical warfare developments are in the infant 
 stage. Even those on the inside of chemical warfare when the 
 Armistice was signed can see to-day things that are certain to 
 come that were undreamed of at that time. This is bound to 
 be so witli-a new weapon. 
 
 To sum up, gas is a universal weapon, applicable to every 
 arm and every sort of action. Since we can choose gases that 
 are either liquid or solid, that are irritating only or highly 
 poisonous, that are visible or invisible, that persist for days 
 or that pass with the wind, we have a weapon applicable to 
 every act of war and for that matter, to every act of peace. 
 But we must plan its use, remembering there is no middle 
 
384 CHEMICAL WARFARE 
 
 ground in war, it is success or failure, life or death. Remember 
 also that training outruns production in a great war, that 
 5,000,000 men can be raised and trained before they can be 
 equipped unless we with proper foresight build up our essential 
 industries, keep up our reserve of supplies, and above all, keep 
 such perfect plans that we can turn all the wheels of peace into 
 the wings of war on a moment ^s notice. 
 
CHAPTER XXIII 
 THE OFFENSIVE USE OF GAS 
 
 What Chemical Warfare Includes 
 
 Chemical Warfare includes all gas, smoke and incendiary 
 materials and all defensive appliances, of which the mask is the 
 principal item, used by the Army. Some of the items or ma- 
 terials in both offense and defense are used by the entire Army, 
 while a few are used only by Chemical Warfare troops. 
 
 The Term ''Gas" 
 
 The term "gas" is now taken to include all materials that 
 are carried to the enemy by the air, after their liberation from 
 cylinders, bombs or shell. It is necessary that this broad use of 
 the term ''gas" be thoroughly understood, because some of these 
 materials are solids, while all others are liquids, until liberated 
 from the containers at the time of the attack. These containers 
 may be special cylinders for cloud gas attacks, special bombs for 
 Livens' projectors and mortars, or artillery shell, and even 
 aviation bombs. Some of the liquids which have a very low 
 boiling point volatilize quickly upon exposure to air, and hence 
 require only enough explosive. to open the shell and allow the 
 liquid to escape. Practically all solids have to be pulverized by 
 a large amount of high explosive, or driven off as smoke by 
 some heating mixture. 
 
 Technical Nature 
 
 Chemical warfare, besides being the newest, is the most tech- 
 nical and most highly specialized Service under the War De- 
 partment. There is no class of people in civil life, and no officers 
 or men in the War Department, who can take up chemical 
 
 385 
 

 386 CHEMICAL WARFARE 
 
 warfare successfully until they have received training in its use. 
 This applies not only "to the use of materials in attack, but to the 
 use of materials for defense. Ten years from now perhaps this 
 will not be true. It is certainly hoped that it will not be. By 
 that time the entire Army should be pretty thoroughly trained 
 in the general principles and many of the special features of 
 chemical warfare. If not, chemical warfare cannot be used in 
 the field with the efficiency and success with which it deserves to 
 be used. Furthermore, it is believed that within ten years the 
 knowledge of the gases used in chemical warfare will be so com- 
 mon through the development of the use of these same materials 
 in civil life, that it will not be so difficult, as at the present date, 
 to get civilians who are acquainted with Chemical Warfare Ser- 
 vice materials, • 
 
 Effectiveness of Gas 
 
 Chemical warfare materials were used during the war by 
 Chemical Warfare Service troops, by the Artillery and by the 
 Infantry. In the future the Air Service and Navy will be added 
 to the above list. Chemical warfare, even under the inelastic 
 methods of the Germans, proved one of the most powerful means 
 of offense with which the American troops had to contend. To 
 realizfi__its_effectiveness we-^ieed onJyj'emember^tlmt more than 
 27_outjif_-every_100 casualties on the_ field of battle were from 
 gas alQne. Unquestionably many of those who died on the battle- 
 field from other causes suffered also from gas. No other single 
 elementjDf war, unless, you call powder a basic element, accounted 
 for so many casualties among the American troops. Indeed, it is 
 believed that a greater number of casualties was not inflicted by 
 any other arm of the Service, unless possibly the Infantry, and 
 even in that case it would be necessary to account for all injured 
 by bullets, the bayonet, machine guns and hand grenades. This 
 is true, in spite of the fact that the German was so nearly com- 
 pletely out of gas when the Americans began their offensive at 
 St. Mihiel and the Argonne, that practically no gas casualties 
 occurred during the St. Mihiel offensive, and only a very few 
 until after a week of the Argonne fighting. Furthermore, the 
 Germans knew that an extensive use of mustard gas against the 
 American lines on the day the attack was made, and also on the 
 
THE OFFENSIVE USE OF GAS 387 
 
 line that marked the end of the first advance a few days later, 
 
 would have produced tremendous casualties. Judging from the 
 
 results achieved at other times by an extensive use of mustard 
 
 gas, it is believed that had the German possessed this gas and 
 
 used it as he had used it a few other times, American casualties i( 
 
 in the Argonne would have been doubled. In fact, the advance 1^^ 
 
 might even have been entirely stopped, thus prolonging the war I ^ 
 
 into the year 1919. "^^ 
 
 OV 
 Humanity of Gas 
 
 A few words right here about the humanity of gas are not \ 
 out of place, notwithstanding the Army and the general public 
 have now so completely indorsed chemical warfare that it is 
 believed the argument of inhumanity has no weight whatever. 
 There were three great reasons jwhy chemical warfare ,.was first 
 widely advertised throughout the world as inhumane and hor- 
 rible. These reasons may be summed up as follows : 
 
 In the first place, the original gas used at Ypres in 1915 was 
 chlorine, and chlorine is one of a group of gases known as 
 suffocants — gases that cause death generally by suffocating the 
 patient through spasms of the epiglottis and throat. That is the 
 most agonizing effect produced by any gas. 
 
 The second reason was unpreparedness. The English had 
 no masks, no gas-proof dugouts, nor any of the_other_4)ara- 
 phernalia t hat w as later employed t o protect against poisonous 
 gas. Consequently, the death rate in the first gas attack at 
 Ypres was very high, probably 35 per cent. As a matter of fact, 
 every man who was close to the front line died. The only ones 
 who escaped were those on the edges of the cloud of gas or so far 
 to the rear that the concentration had decreased below the deadly 
 point. —— ^ 
 
 The third great reason was simply propaganda. It was good Af 
 war propaganda to impress upon everybody the fact that the y 
 German was capable of using any means that he could develop ^f- 
 in order to win a victory. He had no respect for previous agree- ^ 
 ments or ideas concerning warfare. This propaganda kept up j^ 
 the morale and fighting spirit of the Allies, and was thoroughly ^ 
 justifiable upon that score, evenwheirif led To wild exaggeration^ 
 
 The chlorine used in the first attack by the German is the 
 
\U 
 
 388 CHEMICAL WARFARE 
 
 least poisonous of the gases now used. Those later introduced, 
 such as phosgene, mustard gas and diphenylchloroarsine are 
 from five to ten times as effective. 
 
 The measure of humanity for any form of warfare is the 
 percentage of deaths to the total number injured by the par- 
 ticular method of warfare under consideration. 
 
 American Gas Casualties. The t)fficjal list of casualties in 
 ^^ battle as compiled by the Surgeon General's office covering all 
 \fy cases-^eprrrted up to September 1, 1919, is 258,338. Of these 
 ^^"^,752^.^ 27.4 per cent, were gas casualties. Also of the above 
 ^^ — casualties 46,519 resulted in death, of whom about 1,400 only 
 ^^ \ were due to gas. From these figures it is readily deduced that 
 \j^<^^ while 24.85 per cent of all casualties from bullets and high ex- 
 plosives resulted in death, only 2 per cent of those wounded by 
 gas resulted in death. That is, a man wounded on the battle 
 field with gas had twelve times as many chances of recovery as 
 the man who was wounded with bullets and high explosives. 
 
 Fundamentals of Chemical Warfare 
 
 Before taking up in some detail the methods of projecting gas 
 upon the enemy, it is very desirable to understand the funda- 
 mentals of chemical warfare, in so far as they pertain to poison- 
 ous gases. Following the first use of pure chlorine all the 
 principal nations engaged in the war began investigations into a 
 wide range of substances in the hope of finding others more 
 poisonous, more easily produced, and more readily projected 
 upon the enemy. These investigations led to the use of a large 
 number of gases which seriously complicated manufacture, sup- 
 ply, and the actual use of the gases in the field. Gradually a 
 more rational conception of chemical warfare led both the Allies 
 and the enemy to restrict the numbers of gases to a comparative 
 few, and still later to divide all gases into three groups. Thus 
 the German divided his into three groups known as (1) Green 
 Cross, the highly poisonous non-persistent gases, (2) Blue Cross, 
 or diphenylchloroarsine, popularly known as sneezing gas, and 
 (3) Yellow Cross, highly persistent gases, such as mustard gas. 
 In the American Chemical Warfare Service we have finally 
 divided all gases into two primary groups. These groups are 
 
THE OFFENSIVE USE OF GAS 389 
 
 known as "Non-persistent" and "Persistent." The "Non- 
 persistent" gases are those quickly volatilizing upon exposure to 
 the air, and hence those that are carried away at once by air 
 currents, or that in a dead calm will be completely dissipated into 
 the surrounding air in a few hours. If sufficient high explosive 
 be used to pulverize solids, they may be used in the same way, 
 and to a large extent certain highly persistent liquid gases may 
 have their persistency greatly reduced by using a large amount 
 of high explosive, which divides the liquid into a fine spray. 
 The "Persistent" group constitutes those gases that are very 
 slowly volatilized upon exposure to the atmosphere. The princi- 
 pal ones of these now used or proposed are mustard gas and 
 bromobenzylcyanide. For purposes of economy, and hence 
 efficiency, certain gases, both persistent and non-persistent, are 
 placed in a third group known as the ' ' Irritant Group. ' ' These 
 gases are effective in extremely low concentrations against the 
 lungs and other air passages, or the eyes. Diphenylchloroarsine, 
 and some other solids when divided into minute particles by high 
 explosive or heat, irritate the nose, throat and lungs to such an 
 extent in a concentration of one part in ten millions of air as to 
 be unbearable in a few minutes. The tear gases are equally 
 powerful in their effects on the eyes. The irritating gases are 
 used to force the wearing of the mask, which in turn reduces 
 the physical vigor and efficiency of the troops. This reduction 
 in efficiency, even with the best masks, is probably 25 per cent 
 for short periods, and much more if prolonged wearing of the 
 mask is forced. 
 
 Efficiency of Irritant Gases 
 
 One pound of the irritant gases is equal to 50P to 1,000 pounds 
 of other gases when forcing the wearing of the mask alone is de- 
 sired. The great economy resulting from their use is thus appar- 
 ent. Due to the rapid evaporation of the non-persistent gases they 
 are used generally only in dense clouds, whether those clouds be 
 produced from cylinders or from bombs. These gases are used 
 only for producing immediate casualties, as the necessary amount 
 of gas to force the enemy to constantly wear his mask by the use 
 of non-persistent gases alone could not possibly be taken to the 
 front. 
 
390 CHEMICAL WARFARE 
 
 Mustard gas, which is highly persistent and also attacks the 
 lungs, eyes and skin of the body, may and will be used to force 
 the wearing of the mask. It has one disadvantage when it is 
 desired to force immediately the wearing of the mask, and that 
 is its delayed action and the fact that it acts so slowly, and is 
 usually encountered in such slight concentrations that several 
 hours ^ exposure are necessary to produce a severe casualty. For 
 these reasons the enemy may often take chances in the heat of 
 battle with mustard gas, and while himself becoming a casualty, 
 inflict quite heavy casualties upon opposing troops by continuing 
 to operate his guns or rifles without masks. A powerful tear 
 ga.s on the other hand forces the immediate wearing of the mask. 
 
 Materiai. of Chemical Warfare Used by C. W. S. Troops 
 
 Chemical warfare troops, in making gas attacks, use 
 cylinders for the cloud or wave attack, and the Livens' pro- 
 jector and the 4-inch Stokes' mortar for attacks with heavy 
 concentrations of gas projected by bombs with ranges up to 
 a mile. This distance will in the future probably be increased 
 to 1% or 1% miles. The original cylinders used in wave 
 attacks were heavy, cumbersome and very laborious to install, 
 and notwithstanding the wave attack was known to be the 
 deadliest form of gas attack used in the war, fell into disrepute 
 after the use of gas became general in artillery shells and in 
 special bombs. 
 
 Cloud Gas. The Americans at once concluded that since 
 cloud gas attacks were so effective, efforts should be made to 
 make these attacks of frequent occurrence by decreasing the 
 weight of the cylinders, and by increasing the portability and 
 methods of discharging the cylinders. As early as March, 1918, 
 speciflcations for cylinders weighing not more than 65 pounds, 
 filled and completely equipped for firing, were cabled to the 
 United States. They would have been used in large numbers in 
 the campaign of 1919 had the enemy not quit when he did. 
 Toxic smoke candles that are filled with solids driven off by 
 heat will probably be the actual method in the future for put- 
 ting off cloud attacks. The toxic smoke candle is perfectly safe 
 under all conditions and can be made in any size desired. 
 
THE OFFENSIVE USE OF GAS 391 
 
 Cloud gas attacks will be common in the future, and all plans 
 of defense must be made accordingly. They will usually be 
 made at night, when, due to fatigue and the natural sleepiness 
 which comes at that time, men are careless, lose their way, or 
 neglect their masks, and are thus caught unprepared. Ex- 
 perience in the war proved that a wave attack always produced 
 casualties even, as several times occurred, when the enemy or the 
 Allied troops knew some hours beforehand that the attack was 
 coming. The English estimated these casualties to be 10 or 11 
 per cent of the troops exposed. 
 
 Livens' Projectors. The second most effective weapon for 
 using gas by gas troops was and will be the Livens' projector. 
 This projector is nothing less than the simplest form of mortar, 
 consisting of a straight drawn steel tube and a steel base plate. 
 As used during the World War by the Allies it did not even 
 have a firing pin or other mechanism in the base, the electric 
 wires for firing passing out through the muzzle and alongside 
 the drum or projectile which was small enough to permit that 
 method of firing. These were set by the hundreds, very close 
 behind or even in front of the front line trenches. They were 
 all fired at the same instant, or as nearly at the same instant as 
 watches could be sjmchronized, and firing batteries operated. As 
 discussed on page 18 these mortars were emplaced deep enough 
 in the ground to bring their muzzles practically level with the 
 surface. It usually took several days to prepare the attack, and 
 consequently allowed an opportunity for the enemy to detect the 
 work by aeroplane photographs or by raids, and destroy the 
 emplacements by artillery fire. It should be added, however, 
 that notwithstanding this apparent great difficulty, very few 
 attacks were broken up in that way. Nevertheless, in line with 
 the general policy of the American troops to get away from 
 anything that savored of trench warfare, and to make the 
 fighting as nearly continuous as possible with every means avail- 
 able, the American Chemical Warfare Service set at work at once 
 to develop an easy method of making projector attacks. 
 
 It was early found, that, if the excavation was made just 
 deep enough so that the base plate could be set at the proper 
 angle, the drums or projectiles were fired as accurately as when 
 the projectors or mortars were set so that the muzzles were level 
 
392 CHEMICAL WARFARE 
 
 with the surface. The time required to emplace a given number 
 of mortars in this way was only about one-fifth of that required 
 for digging them completely in. 
 
 Coupled of course with these proposed improvements in 
 methods, studies were being made and are still being made 
 to produce lighter mortars, better powder charges, and better 
 gas checks in order to develop the full force of the powder. 
 Many improvements along this line can be made, all of which 
 will result in greater mobility, more frequent attacks, and 
 hence greater efficiency. 
 
 4-Iiich Stokes' Mortar. The Stokes' mortar is not different 
 from that used by the Infantry, except that it is 4-inch, while 
 the Infantry Stokes' is 3-inch. The 4-inch was chosen by the 
 British for gas, as it was the largest caliber that could be 
 fired rapidly and yet be moderately mobile. Its range of 
 only about 1,100 yards handicapped it considerably. The poor 
 design of the bomb was partly responsible for this. The powder 
 charges also were neither well chosen nor well designed. It 
 is believed that great improvements can be made in the shape 
 of the bomb and in the powder charge, which will result in 
 much longer range and high efficiency, while in no way increas- 
 ing the weight of the bomb or decreasing the rate of fire. 
 These last two weapons were used during the World War, 
 and will be very extensively used in the future for firing high 
 explosive, phosphorus, thermit and similar materials that non- 
 technical troops might handle. 
 
 Since gas has proven without the shadow of a doubt, that 
 it will produce more casualties for an equal amount of material 
 transported to the front than any other substance yet devised, 
 ^\l troops using short range guns or mortars should be trained 
 to fire gas whenever weather conditions are right. When 
 weather conditions are not right, they should fire the other 
 substances mentioned. The Livens' projector with its 60 pound 
 bomb, of which 30 pounds will be gas or high explosive, is 
 a wonderful gun up to the limit of its range. The bomb, not being 
 pointed, does not sink into the ground, and hence upon explod- 
 ing exerts the full force of high explosive upon the surround- 
 ings, whether bombs, pill boxes, barbed wire or trenches, to 
 say nothing of personnel. 
 
h 
 
 THE OFFENSIVE USE OF GAS 393 
 
 High Explosive in Projectors. When these are burst by 
 ihe hundreds on a small area everything movable is blotted 
 out. Thus concrete machine gun emplacements, lookout sta- 
 tions, bomb-proofs and wire entanglements are destroyed, 
 trenches filled up, and the personnel annihilated. This was 
 amply demonstrated on the few occasions when it was actually 
 used at the front. The American Infantry, wherever they 
 saw it tried out, were wild to have more of it used. The Ger- 
 man was apparently equally anxious to have the use stopped. 
 It is, however, one of the things that must be reckoned with 
 in the future. It means practically that No Man's Land in 
 the future will be just as wide as the extreme range of these 
 crude mortars — and here a word of caution. While efforts 
 have been made to increase the range of these mortars, whether 
 of the Livens' projector or Stokes' variety, no further increase 
 will be attempted when that increase reduces the speed of 
 firing or the efficiency of the projectile. In other words results 
 depend upon large quantities of material delivered at the same 
 instant on the point attacked, and if this cannot be obtained 
 the method is useless. For this reason these mortars will 
 never be a competitor of the artillery. The artillery will have 
 all that it can do to cover the field within its range — beyond 
 that reached by the mortars. 
 
 Phosphorus in 4-Inch Stokes. Phosphorus will be used 
 largely by gas troops, but only in the 4-inch or other Stokes' 
 mortar that may be finally adopted as best. The Livens' pro- 
 jector carries too great a quantity, and being essentially a 
 single shot gun, is not adapted to keeping up a smoke screen 
 by slow and continued firing, or of being transported so as to 
 keep up with the Infantry. Phosphorus has also very great 
 value for attacking personnel itself. Any one who has been 
 burned with phosphoi'us or has witnessed the ease with which 
 it burns when exposed to air, wet or dry, has a most whole- 
 some fear of it. The result of it in the war showed that the 
 enemy machine gunners or other troops would not stand up 
 under a bombardment of phosphorus fired from the 4-inch 
 Stokes' mortar — each bomb containing about seven pounds. 
 
 Thermit. Thermit is used in the same way, and while 
 the idea of molten metal, falling upon men and burning 
 
394 CHEMICAL WARFARE 
 
 through clothing and even helmets, is attractive in theory, it 
 proved absolutely worthless for those purposes on the field 
 of battle. It was found impossible to throw sufficiently large 
 quantities of molten metal on a given spot to cause any con- 
 siderable burn. In other words, the rapid spreading out and 
 cooling of the metal almost entirely ruined its effectiveness, 
 except its effect on the morale. This latter, however, was 
 considerable, as one might judge from seeing the thermit shells 
 burst in air. For this reason thermit may find a limited use 
 in the future. 
 
 The Spread of Gas 
 
 Height of Gas Cloud. The height to which gas rises in a 
 gas cloud is not exactly known, but it is believed to be not 
 much more than fifty feet, and then only at a considerable 
 distance from the point of discharge. Moving pictures taken 
 of gas clouds show this to be true. It is also indicated by 
 the fact that pigeons, which are very susceptible to poisonous 
 gas, practically always return to their cages safely when 
 liberated in a gas cloud. This was a good deal of a mystery 
 until it was realized that the pigeon escaped through his rising 
 so quickly above the gas. This of course would be expected 
 v/hen it is known that practically all gases successfully used 
 were two or more times as heavy as air. Such gases rise only 
 by slow diffusion, or when carried upAvards by rising currents. 
 The absence of these upward currents at night is one of the 
 reasons why gas attacks are more effective at night than dur- 
 ing the day. 
 
 Horizontal Spread of Gas. Another important thing to 
 know in regard to the behavior of the wave of gas is the 
 horizontal spread of a cloud. If gas be emitted from a cylinder 
 the total spread in both directions from that point is from 
 20° to 30° or an average of 25°. This varies, of course, with 
 the wind. The higher the wind the less the angle, though 
 the variation due to wind is not as great as might be expected. 
 This horizontal spread of the gas cloud was measured experi- 
 mentally, and the results checked by aeroplane pictures 
 of heavy wave attacks over the enemy line. In the latter 
 case the path of the gas was very closely indicated by the 
 
THE OFFENSIVE USE OF GAS 395 
 
 dead vegetation. This vegetation was killed and bleached 
 so that it readily showed up in aeroplane photographs. The 
 visibility of a gas clond arises from the fact that when a 
 large amount of liquid is suddenly evaporated, the air is cooled 
 and moisture condensed, thereby creating a fog. With gases 
 such as mustard gas and others of slight volatility, a visible 
 cloud is not formed. For purposes of identification of points 
 struck by shell, smoke substances are occasionally added, or 
 a few smoke shell fired with the gas shell. * As future battle 
 fields will be dotted everywhere with smoke clouds, a point 
 that will be discussed more fully later, the firing of smoke 
 with gas shell will probably be the rule and not the exception. 
 
 Requirements of Successful Gas 
 
 If we succeed in getting a poisonous gas that has no odor 
 it will be highly desirable to fire it so that it will not be visible. 
 In that case no smoke will be used. Carbon monoxide is such 
 a gas, but there are several important reasons why it has not 
 been used in war. (See page 190). These considerations 
 indicate the general requirements for a successful poisonous 
 gas. If non-persistent it must be quickly volatilized, or must 
 be capable of being driven off by heat or by other means, 
 which can be readily and safely produced in the field. It 
 must be highly poisonous, producing deaths in high concen- 
 trations, and more or less serious injuries when taken into 
 the system in quantities as small as one-tenth of that necessary 
 to produce death. If it has a slightly delayed action with no 
 intervening discomfort, it is still better than one that produces 
 immediate discomfort and more or less immediate action. It 
 must be readily compressed into a liquid and remain so at 
 ordinary temperatures, with the pressure not much above 
 25 or 30 pounds per square inch. 
 
 As a persistent gas it must be effective in extremely low 
 concentrations, in addition to having the other qualities men- 
 tioned above. 
 
 These general characteristics concerning gases apply 
 whether used by Chemical "Warfare troops, the Artillery, the 
 Air Service, the Navy, or the Infantry. In speaking of these 
 
396 CHEMICAL WARFARE 
 
 substances being used by the Infantry, it is understood that 
 an ample number of Chemical Warfare officers will be 
 pi'esent to insure that the gases may not be turned loose when 
 weather conditions are such that the gas might drift back and 
 become a menace to our own troops. This is absolutely essen- 
 tial since no troops who have as varied duties to perform as 
 the Infantry, can be sufficiently trained in the technical side 
 of chemical warfare to know when to put it off on a large 
 scale with safety and efficiency. 
 
 Artillery Use op Gas 
 
 The Artillery of the future will probably fire more gas than 
 any other one branch of the Army. Tliere are two reasons 
 for this — first, the large number of guns now accompanying 
 every Army, and second, the long range of many of these 
 guns. As before indicated, the gases are adaptable to various 
 uses, and hence to guns differing both in caliber and range. 
 The gas will be fired by practically all guns — from the 75 mm. 
 to the very largest in use. It is even possible that if guns 
 smaller than the 75 mm. become generally useful that certain 
 gases will be fired by them. 
 
 Efficiency of Artillery Gas Shell. It is well to remember 
 in the beginning that all artillery shell so far designed and 
 used, contain only about 10 per cent gas, i.e., 10 per cent of 
 the total weight of shell and gas. It is hoped that gas shell 
 may later be so designed that a somewhat greater proportion 
 of the total weight of the shell will be gas than is now true. 
 This is very desirable from the point of efficiency. As stated 
 above the bombs used by Chemical Warfare troops contain 
 nearly 50 per cent of their total weight in gas, and hence are 
 nearly five times as efficient as artillery shell within the limit 
 of range of these bombs. This fact alone is enough to warrant 
 the use of gas troops to their full maximum capacity in order 
 that the artillery may not fire gas at the ranges covered. 
 
 Guns Firing Persistent and Non-Persistent Gases 
 
 Considering the firing of non-persistent and persistent 
 gases, it may be said generally that non-persistent gases will 
 
THE OFFENSIVE USE OF GAS 397 
 
 be fired only by the medium caliber guns which are available 
 in large numbers. In fact, the firing of non-persistent gases 
 will be confined mainly to the 6-inch or 155 mm. Howitzer 
 and gun. 
 
 As our Army was organized in France, and as it is organ- 
 ized at present, the number of 155 mm. guns will be greater 
 than all others 'put together, except the 75 mm. In order that 
 a non-persistent gas may be most effective a high concentration 
 must be built up very quickly. This necessitates the use of 
 the largest caliber shell that are available in large numbers. 
 Of course, a certain percentage of the gas shell of other calibers 
 may consist of non-persistent gases in order to help out the 
 155 mm. gun. This is in accordance with the present program 
 for loading gas shell and applies particularly to the 8-inch and 
 240 mm. Howitzer. 
 
 Few Ideally Persistent or Non-Persistent Gases. Naturally 
 there will be very few gases that are ideally non-persistent 
 or ideally persistent. The gi^oups will merge into one another. 
 Those on the border line will be arbitrarily assigned to one 
 group or the.other. It might be said definitely, however, that 
 a gas which will linger more than six or possibly eight hours 
 under any conditions, except great cold, will not be considered 
 non-persistent. For reasons of efficiency and economy per- 
 sistent gases will not be chosen unless they will persist under 
 ordinary conditions for two or three days or more. Accord- 
 ingly, a gas which would persist for one day only would have 
 to be extraordinarily useful to lead to its adoption. 
 
 Firing Non-Persistent Gases. Of the non-persistent gases 
 phosgene is the type and the one most used at present. 
 Furthermore, so far as can now be foreseen, it will continue 
 to be the non-persistent gas most used. It volatilizes very 
 quickly upon the bursting of the shell. Accordingly, in order 
 that the shell fired at the beginning of a gas ''shoot," as they 
 are generally referred to in the field, shall still be effective 
 v/hen the last shell are fired, it is necessary that the whole 
 number be fired within two to three minutes. The temperature 
 and velocity of the wind both affect this. If it be in a dead 
 calm, the time may be considerably extended ; if in a consider- 
 able wind, it must be shortened. Another important considera- 
 
398 CHEMICAL WARFARE 
 
 tion requiring the rapid firing of non-persistent gases is the 
 fact that nearly all masks thoroughly protect against phosgene 
 and similar gases. It is accordingly necessary to take the 
 enemy unawares and gas him before he can adjust his mask; 
 otherwise, practically no harm will result. From the con- 
 siderations previously mentioned, these *'gas shoots" are 
 usually made at night when, as before stated, carelessness, 
 sleepiness and the resulting confusion of battle conditions 
 always insure more casualties than firing gas in the daytime. 
 
 Firing Persistent Gases. The persistent gases will be fired 
 by all caliber guns, but to a less extent by the 155 mm. than 
 by the other calibers. Persistent gases must be sufficiently 
 effective in low concentrations to act more or less alone. If 
 it be desirable to fill an atmosphere over a given area with 
 mustard gas, the firing may extend for two or three, or even 
 five or six hours and all shell still act together. The same is 
 true of bromobenzylcyanide. This, then, permits the minimum 
 number of guns to be used in firing these persistent gases. 
 Inasmuch as they persist and force the wearing of the mask, 
 they are available for use in long-range, large-caliber guns 
 for interdiction firing on cross-roads, in villages, and on woods 
 that afford hiding places, as well as on other similar concentra- 
 tion points. 
 
 Firing Irritant Gases. The irritant gases will be fired by 
 the various caliber guns, in the same manner as the persistent 
 and non-persistent gases. We will have non-persistent irritant 
 gases and persistent irritant gases. They are, however, con- 
 sidered as a group because they are used for harassing pur- 
 poses, due to their efficiency in forcing the wearing of the 
 mask. 
 
 Before the signing of the Armistice, the General Staff, 
 A. E. F., had authorized, beginning January 1, 1919, the filling 
 of 25 per cent of all shell with Chemical Warfare materials. 
 The interpretation there given to shell was that it included 
 both shrapnel and high explosive. 
 
 Of the field guns in use, the 75 mm. will be best, up to the 
 limit of its range, for persistent gases such as mustard gas, 
 and the tear gas, bromobenzylcyanide. A considerable number, 
 however, were filled with non-persistent gases and probably 
 
rTHE OFFENSIVE USE OF GAS 399 
 
 will continue to be so, since, due to the very large number 
 of 75 mm. guns available, they can be used to add greatly 
 at times to the amount of non-persistent gas that can be fired 
 upon a given point. 
 
 Use of Gas by the Aviation Service 
 
 No gas was used by aeroplanes in the World War. Many 
 rumors were spread during the latter part of the war to the 
 effect that the Germans had dropped gas here or there from 
 aeroplanes. Every such report reaching the Chemical Warfare 
 Service Headquarters was run down and in every case was 
 found to be incorrect. However, there was absolutely no 
 reason for not so using gas, except that the German was 
 afraid. In the early days of the use of gas he did not have 
 enough gas, nor had he developed the use of aeroplanes to 
 the point where it would have seemed advisable. When, how- 
 ever, he had the aeroplanes the war had not only begun to go 
 against him, but he had become particularly fearful of gas and 
 of aeroplane bombing. 
 
 It does not seem to be generally known, but it is a fact, 
 that after three or four months' propaganda he made a direct 
 appeal to the Allies to stop the use of gas sometime during 
 the month of March, 1918. This propaganda took the form 
 of an appeal by a Professor of Chemistry who had access to 
 Switzerland, to prevent the annihilation of the Allied forces 
 by a German gas that was to make its appearance in 1918. 
 This German professor claimed that, while favoring the Ger- 
 mans winning the war, he had too much human sympathy to 
 desire to see the slaughter that would be caused by the use 
 of the new gas. The Allies in the field felt that this was 
 simply an expression of fear and that he did not have such 
 a gas. The Germans were accordingly informed that the Allies 
 would not give up the use of gas. Later events proved 
 these conclusions to be absolutely correct. The German evi- 
 dently felt that the manufacturing possibilities of the Allies 
 would put them in a more predominant position with gas than 
 with anything else. In that he was exactly correct. 
 
 The use of gas by aeroplanes will not differ from its 
 
400 CHEMICAL WARFARE 
 
 use in artillery or by Chemical Warfare Troops. Non- 
 persistent gases may be dropped on the field of battle, upon 
 concentration points, in rest areas, or other troop encamp- 
 ments to produce immediate casualties. Persistent gases will 
 be dropped particularly around cross-roads, railroad yards, 
 concentration points and encampments that cannot be reached 
 by the artillery. The sprinkling of persistent gases will be one 
 of the best ways for aeroplanes to distribute gas. 
 
 It might be said here that the aviation gas bomb will be 
 highly efficient, inasmuch as it has to be only strong enough 
 to withstand the low pressure of the gas and ordinary hand- 
 ling, whereas artillery shell must be strong enough to with- 
 stand the shock of discharge in the gun. 
 
 Infantry and Gas Warfare 
 
 When one suggests the possibility of the infantry handling 
 gas, it is at once argued that the infantry is already over- 
 loaded. That is true, but in the future, as in the past, the 
 infantryman will increase or decrease his load of a given 
 material just as its efficiency warrants. If he finds that gas 
 will get casualties and help him win victories more readily 
 than an equal weight of any other material, he will carry 
 gas material. A study of the articles of equipment abandoned 
 by 10,000 stragglers in the British Army picked up during the 
 great German drive towards Amiens in March, 1918, illus- 
 trates this very clearly. Of the equipment carried by these 
 stragglers, more than 6,000 had discarded their rifles. The 
 helmets were thrown away to a somewhat less extent, but the 
 gas mask had been thrown away by only 800 out of the 10,000. 
 Now the gas mask is not a particularly easy thing to carry, 
 nor was the English type comfortable to wear, but the English 
 soldier had learned that in a gas attack he had no chance 
 whatever of escape if his gas mask failed him. Accordingly, 
 he hung on to the mask when he had discarded nearly every- 
 thing else in his possession. The same thing will be true of 
 any gas equipment if it proves its worth. 
 
THE OFFENSIVE USE OF GAS 401 
 
 Smoke and Incendiary Materials 
 
 So far nothing has been said in regard to smoke or incen- 
 diary materials. This has been due to the fact that their 
 use is not dependent upon' weather conditions to anything near 
 the extent that gas is. Second, the smokes, not being poison- 
 ous, are not a danger to our own troops, although they may 
 hamper movements and add to the difficulty of taking a posi- 
 tion, if used improperly. Of the two classes of materials, 
 smoke and incendiary, smoke materials may be said to be at 
 least a thousand times as important as the incendiary materials. 
 A material that will burst into flame when a shell is opened 
 or that will scatter balls of burning fire appeals to the popular 
 imagination, and yet actual results achieved by such materials 
 on the field of battle have been almost nil. About the only 
 results worth while achieved by incendiary materials have 
 been in occasionally firing ammunition dumps and more fre- 
 quently, setting fire to warehouses and other storage places. 
 This will undoubtedly continue in the future. 
 
 Flame Thrower 
 
 Of the incendiary materials the least valuable is the flame 
 tlirower. In the Chemical Warfare Service it has been the 
 habit for a long while not to mention the flame thrower at 
 all, unless questions were asked about it. It is mentioned 
 here to forestall the questions. Even the German, who invented 
 it and who, during the two years of trench warfare, had full 
 opportunity for developing its use, finally came to using it 
 largely as a means of executing people that he did not want 
 to shoot himself. Men falling in that class were equipped 
 with flame throwers and sent over the top. The German knew, 
 as did the Allies, that each man with a flame thrower became 
 a target for every rifle and machine gun nearby. The flame 
 thrower is very quickly exhausted and then the one equipped 
 with it has no means of offensive action, and in addition, is 
 saddled with a heavy load, hampering all movements, whether 
 to escape or to advance. 
 
402 CHEMICAL WARFARE 
 
 Inflammable Materials 
 
 There will probably be some use for materials such as 
 metallic sodium, spontaneously inflammable oils, etc., that will 
 burst into flame and burn when exposed to the air, though 
 white phosphorus is probably equal, and in most cases vastly 
 superior to anything else so far suggested. Phosphorus burns 
 with an unquenchable flame when exposed to the air, whether 
 wet or dry. It is of great value for screening purposes, and 
 for use against the enemy's troops. The German did not use 
 phosphorus simply because he did not have it, just as he did 
 not use helium in his observation balloons because he did not 
 have it. 
 
 The value of phosphorus was just beginning to be realized 
 slightly when the Americans entered the war, while its full 
 value was not appreciated even by the American troops when 
 the war closed. 
 
 The work of the First Gas Regiment with phosphorus 
 against machine gun nests proved how valuable it is against 
 the enemy's troops. It proved also its tremendous value as a 
 screen. 
 
 The Chemical "Warfare Service was prepared to fill a great 
 number of artillery shell with phosphorus, but due to the 
 failure of our shell program to mature before the Armistice, 
 phosphorus was not used by American artillery to any appre- 
 ciable extent. 
 
 Smoke Used by Everyone 
 
 Smoke will be used by every fighting arm of the Service 
 in practically every battle, both by day and by night. If you 
 have ever tried on a target range to shoot at a target that was 
 just beginning to be obscured by a fog, you will recognize 
 the difficulty of hitting anything by firing through an impene- 
 trable smoke screen. It is simply a shot in the dark. Future 
 battles will witness smoke formed by smoke candles that are 
 kept in the trenches or carried by the troops, by smoke from 
 bursting artillery shell and rifle grenades, by smoke from 
 aeroplane bombs and possibly even from what is known as 
 the smoke knapsack. The knapsack produces a very dense 
 
THE OFFENSIVE USE OF GAS 403 
 
 white smoke and very economically, but will probably not 
 be much used. This is because, notwithstanding its efficiency, 
 the knapsack cannot be projected to a distance, that is, the 
 smoke screen is generated on the person carrying the knap- 
 sack. On the other hand the great value of phosphorus is that 
 it can be fired to great distances in rifle grenades or artillery 
 shell, and dropped from aviation bombs. The smoke screen 
 is thus established in front of the object it is desired to cut 
 off, whether it be a battery of artillery, an advancing wave 
 of infantry, or a lookout station. Thus smoke, for screening 
 purposes alone, will be used to a tremendous extent. It will 
 also be used in conjunction with gas. 
 
 Smoky Appearance op Gas Cloud 
 
 4 
 
 Due to the smoky appearance of an ordinary gas cloud and 
 to the coming use of poisonous smokes, no one on the field 
 of battle in the future will ever be certain that any given 
 smoke cloud is not also a poisonous cloud until he has actually 
 tested it. And there lies an opportunity for the most intense 
 study and for the greatest use of the proverbial American 
 ingenuity that war has ever furnished. 
 
 In the variations that can be played with smoke containing 
 gas, or not containing gas, with smoke hurled long distances 
 by the artillery or dropped from aeroplanes, the possibilities 
 indeed are unlimited. Every officer will need to study the 
 < possibilities of smoke, both in its use against him and in 
 his use of it against the enemy. He can probably save more 
 casualties among his own troops by the skillful use of smoke 
 than by any other one thing at his command. On the 
 other hand, the unskilled use of smoke on the part of one 
 side in a battle may lead to very great casualties in proportion 
 to those of the enemy should the latter use his smoke skill- 
 fully. This is a subject that deserves deep and constant study. 
 
 Protection by Smoke Clouds 
 
 Smoke in the future will be the greatest protective device 
 
 ^ available to the soldier. It shuts out not only the view in 
 
 daylight, but the searching of ground at night by search- 
 
404 CHEMICAL WARFARE 
 
 lights, by star bombs or other means for illuminating the battle- 
 field. It has already been used extensively by the Navy and 
 undoubtedly will be used far more extensively in the future. 
 
 Shell Markings 
 
 Modern artillery shell have distinctive colors for high 
 explosive, for shrapnel, for incendiary materials, and for gases. 
 A grayi sh color has been adopted as the general color of 
 the paint on all gas shells, bombs and cylinders. In addition 
 a system of colored bands has been adopted. These bands are 
 white to indicate poisonous non-persistent substances, and red — 
 persistent. Yellow is used to indicate smoke. With any given 
 combination of red and white and yellow bands, the artillery- 
 man at the front can tell, at a glance, whether the gas is non- 
 persistent or whether it is persistent, and also whether or not 
 it contains smoke. There will be secondary markings on each 
 shell which, to the trained Chemical AVarfare Service officer, 
 will indicate the particular gas or gases in the shell. These 
 markings however, will be inconspicuous and no attempt will 
 be made to give the information to the soldier or even to the 
 average officer firing gas. 
 
 These secondary markings are for the purpose of enabling 
 the Chemical Warfare Service officers in charge to use certain 
 gases for particular uses in those comparatively rare cases 
 when sufficient gas is on hand and sufficient time available to 
 enable such a choice to be made. 
 
CHAPTER XXIV 
 DEFENSE AGAINST GAS 
 
 (From the Field Point of View) 
 
 The best defense against any implement of war is a vigorous 
 offense with the same implement. This is a military axiom that 
 cannot be too often, or too greatly emphasized, though like other 
 axioms it cannot be applied too literally. It needs a proper in- 
 terpretation — the interpretation varying with time and circum- 
 stances. Thus in gas warfare, a vigorous offense with gas is the 
 best defense against gas. This does not mean that the enemy 's gas 
 can be ignored. Indeed, it is more important to make use of all 
 defensive measures against gas than it is against any other form 1 
 of attack. G as being heavier than air, rolls along the groun d,^^' r 
 filling dugouts, trenches, wo ods and jyalleys — ^just th e places | ^^ y 
 that'^ are safest from bullets and high ex plosive s. There it ^^ 
 remains for hours after it has blown away in the open, and, ^^\i( 
 since the very air itself is poisoned, it is necessary not only that 
 protection be general but that it be continuous during the whole 
 time the gas is present. 
 
 Earliest Protective Appliances 
 
 The earliest protection against gas was the crudest sort of a 
 mask. The first gas used was chlorine and since thousands of 
 people in civil life were used to handling it, many knew that 
 certain solutions, as hj^posulfite of soda, would readily destroy it. 
 They also knew that if the breath could be drawn through 
 material saturated with those solutions, the chlorine would be 
 destroyed. Thus it was that the first masks were simple cotton, 
 or cotton waste pads, which were dipped into hyposulfite of soda 
 solutions and applied to the mouth and nose during a gas attack. 
 
 405 
 
406 CHEMICAL WARFARE 
 
 These pads were awkward, unsanitary, and, due to the long inter- 
 vals between gas attacks, were frequently lost, while the solution 
 itself was often spilled or evaporated. The net i:esult of all this 
 was poor protection and disgust with the so-called masks. 
 
 Design of New Masks 
 
 After using these, or similar poor excuses for a mask, for a 
 few weeks', the British designed what was known as the PH 
 helmet. In a gas attack the sack was pulled over the head and 
 tucked under the blouse around the neck, the gas tight fit being 
 obtained by buttoning the blouse over the ends of the sack. This 
 PH helmet was quite successful against chlorine and, to a much 
 less extent, against phosgene, a new gas introduced during the 
 spring of 1916. 
 
 But it was warm and stuffy in summer — the very time when 
 gas is used to the greatest extent — while the chemicals in the 
 cloth irritated the face and eyes, especially when combined with 
 some of the poisonous gases. 
 
 Probably as a result of experience with oxygen apparatus in 
 mine rescue work. Colonel Harrison suggested making a mask 
 of which the principal part was a box filled with chemicals and 
 carried on the chest. A flexible tube connected the box with a 
 mouth-piece of rubber. Breathing was thus through the mouth 
 and in order to insure that no air would be breathed in through 
 the nose, a noseclip was added. 
 
 This, of course, cared for the lungs, but did not protect the 
 eyes. Their protection was secured by making a facepiece of 
 rubberized cloth with elastics to hold it tight against the face. 
 The efficiency of this mask depends, then, first upon the ability 
 of the facepiece to keep out lachrymatory gases which affect the 
 eyes, and, second, upon a proper combination of chemicals in the 
 box, to purify the air drawn into the lungs throilgh the mouth- 
 piece. (Details are given in Chapter XII). 
 
 Protection Against Smoke \ 
 
 While the charcoal and soda lime granules furnished an 
 adequate protection against all known true gases, they did not 
 furnish protection against certain smokes or against minute 
 
DEFENSE AGAINST GAS 407 
 
 particles of liquid gas. Since certain smokes, as stannic chloride, 
 though not deadly, are so highly irritating as to make life un- 
 bearable, it early became necessary to devise means for keeping 
 them from going through the masks. This was done in the first 
 masks by adding a sufficient thickness of cotton batting. The 
 cotton was usually placed in three layers alternating with the 
 charcoal and granules, as it was thought the latter would be held 
 in place better by that means. 
 
 Some time after stannic chloride came into use the Germans 
 started firing shells containing a small quantity of diphenyl- 
 cliloroarsine, popularly known as ** Sneezing Gas.'* Protection 
 against this is discussed in Chapter XVIII. 
 
 Choice of Masks for U. S. Troops 
 
 When it became necessary, with the creation of a Chemical 
 Warfare Service in France in August, 1917, to decide upon a 
 mask for American troops, there were available for purchase 
 two types — the British type and the French M-2. The French 
 M-2 consisted essentially of 32 layers of cloth impregnated with 
 various chemicals, through which the air was breathed both in 
 and out. This mask was quite effective against ordinary field 
 concentrations of most gases, but was utterly inadequate to care 
 for the high concentration of phosgene obtained in the front 
 line from cloud gas or from projector gas attacks. It was also 
 poor against chloropicrin. The M-2 was, however, very light and 
 easy to carry and moreover was deemed sufficient to protect 
 against concentrations of cloud gas even, at points more than 
 five miles distant from the front line. 
 
 Furthermore, it was felt desirable at first to have an auxiliary 
 or emergency mask in addition to the principal one, for use in 
 case the principal mask was worn out or damaged. Accordingly 
 both types of masks were adopted and the day after Fries took 
 charge of the Chemical Warfare Service, A.E.F., on August 
 22, 1917, 100,000 of each were purchased, although there were 
 then only ten or twelve thousand American troops in France 
 requiring masks. Later additional masks of both kinds were 
 purchased to tide over the American troops until a sufficient 
 quantity of the British type masks could be manufactured in 
 
408 CHEMICAL WARFARE 
 
 the United States. The total of British masks purchased 
 amounted to about 700,000, 
 
 However, within a comparatively short time after American 
 troops got into the front line it was realized that a second mask, 
 inferior in protection to the first, was highly undesirable. Dur- 
 ing a gas attack men seemed to acquire an uncontrollable desire 
 to shift from one mask to the other. This shifting in nearly 
 every case resulted in a casualty. We then came rapidly to the 
 conclusion that one mask only should be furnished, and that 
 one the liest that could be made, and then to impress upon the 
 soldier the fact that his life depended upon the care he took of 
 his mask. This proved to be an entirely sound conclusion, as 
 the number of men gassed through injuries to the mask was 
 comparatively small. An interesting proof of the value the 
 soldier placed upon his mask was shown by the articles of equip- 
 ment thrown away by 10,000 British stragglers in the great 
 German offensive of March, 1918. Of the articles thus thrown 
 away the gas mask came at the foot of the list, with only 800 
 missing. The steel helmet is said to have come next with about 
 4,000 missing. 
 
 Sizes of Faces for Masks 
 
 "When adopting the British respirator in August, 1917, it 
 was decided that the American face as well as the American 
 stature was probably larger than the English. Accordingly 
 inquiry was made in regard to the sizes of masks issued to the 
 Canadians as it was thought probable they required a greater 
 proportion of the larger size masks than did the English. When 
 prescribing the relative quantities of each size of mask to be 
 furnished Americans, the Canadian requirements were taken as 
 a base but with the larger sizes increased slightly over the 
 Canadian requirements. As a matter of fact even these in- 
 creases proved considerably too small, so that the numbers in the 
 two sizes above normal had to be finally more than doubled. 
 
 Objections to German Type Mask 
 
 The American Gas Service felt from the beginning that a 
 design which attached the box of chemicals to the facepiece was 
 
DEFENSE AGAINST GAS 409 
 
 unsound in principle (this design was used in the German mask 
 and in the French A. R. S. masks), since it did not allow proper 
 flexibility for increasing the size of the box to care for new 
 gases. Furthermore, the weight of the box during movement 
 caused the facepiece to swing slightly from side to side. This 
 interfered with vision and tended to lift the facepiece away 
 from the face and allow gas to enter. That the objections of the 
 American Gas Service to this type were correct was proved by 
 the difficulty encountered toward the end of the war by both the 
 French and the Germans in trying to provide a suitable filter 
 for protection against particulate clouds and the smokes, such as 
 stannic chloride and diphenylchloroarsine. 
 
 Struggle Between Mask and Gas 
 
 As between the mask and poisonous gases, we have the old 
 struggle of the battleship armor against the armor-piercing pro- 
 jectile. While the armor-piercing projectile has always had a 
 little the better of the game, it is just the reverse with gases. 
 The gas mask has always been just a little better than the gases, 
 so that very few casualties have occurred through failure of the 
 mask itself. This margin of safety has never been any too great, 
 and that we have had a margin at all is due to the energy, skill and 
 enthusiasm of those developing and manufacturing masks in 
 England, France, and particularly in the United States. 
 
 However, the mask at the best is uncomfortable, causes some 
 loss of vigor, and even with the very best American masks there 
 is some loss in vision. The wearing effect on troops results 
 mostly from the increased resistance to breathing. Accordingly 
 a tremendous amount of study and effort was made to decrease 
 this breathing resistance. In the English type masks this 
 resistance was equal to the vacuum required to raise a column 
 of w^ater about four and one-half inches. Adding the sulfite 
 paper to protect against diphenylchloroarsine increased this 
 resistance by about one inch. This put a heavy burden on the 
 wearer of the mask whenever it was necessary for him to do any 
 manual labor while wearing it. In addition earlier masks left a 
 good deal to be desired in the way of reducing resistance by 
 proper sized tubes, angles and valves through which the air was 
 
410 CHEMICAL WARFARE 
 
 drawn. This was much more easily overcome than reducing the 
 resistance through the chemicals and charcoal and the materials 
 for protection against diphenylchloroarsine. In the latest type 
 canister, devised after long trials for the American forces, this 
 resistance was brought down to about two inches of water. "What 
 this reduction in resistance means no one knows except one who 
 has worn the old mask with its mouth-piece and four to six 
 inches' resistance and has then replaced that mask for one 
 through which he breathes naturally with only two inches' 
 resistance. 
 
 Design of New American Mask 
 
 The American Gas Service felt from the beginning that the 
 mouth-piece and noseclip must be abandoned and bent every 
 effort toward getting a mask perfected for that purpose. The 
 English opposed this view fiercely for nearly a year. This 
 position on the part of the English was more or less natural. 
 They developed their mask in the beginning for protection 
 against cloud gas. In those days the opposing trenches were 
 close together. Moreover, front line trenches were quite strongly 
 manned. The result was that a large number of men were 
 exposed to a very high concentration of gas, but — and highly 
 important — for a short period only. Inasmuch as the German 
 feared this cloud gas even more than the English there was no 
 danger of his attacking in it. The English rules of conduct 
 during a gas attack called for all movement to stop and for 
 every man to stand ready until the cloud passed. Accordingly, 
 the man was breathing the easiest possible and hence did not 
 suffer particularly from the resistance. 
 
 With the advent of mustard gas, however, the whole general 
 scheme of protection changed. Mustard gas, as is well known, 
 is effective in extremely low concentrations and has very great 
 persistency. In dry warm weather mustard gas, scattered on 
 the ground and shrubbery, will not be fully evaporated for two 
 to three days and accordingly will give off vapors that not only 
 burn the lungs and eyes but the soft, moist parts of the skin as 
 well. In cool, damp weather the gas remains in dangerous 
 quantity for a week and occasionally longer. Since this gas, in 
 liquid form, evaporates too slowly for use in gas clouds, it is 
 
DEFENSE AGAINST GAS 411 
 
 used altogether in bombs and shells. Accordingly it could be 
 expected to be and actually is fired at all ranges from the front 
 line to nearly eight miles back of that line. Hence, with the 
 coming of mustard gas, the need for protection changed from 
 high protection for a short period to moderate protection for very 
 long periods. Indeed, mustard gas makes it necessary for men 
 to wear masks just as long as they remain in an area infected 
 with it. There is still occasional need for high protection for 
 short periods, but with the increase in the efficiency of charcoal 
 alone, it is found that the amount of charcoal and chemicals in 
 the canister can be very greatly reduced and still maintain 
 sufficient protection for the high concentrations encountered in 
 cloud gas and projector attacks. 
 
 Exhaustion and Malingering 
 
 It seems physically impossible for the ordinary man to wear 
 the British mask with its mouth-piece and noseclip more than 
 six to eight hours and vast numbers are unable to even do that. 
 How many thousands of casualties were suffered through men 
 losing their mental balance from exhaustion and the discomfort 
 of -the mouth-piece and noseclip no one knows. Such men tore 
 off the mask, stating that they would rather die than endure the 
 torture of wearing it longer. Furthermore, the poor vision of 
 this mask led to the habit of taking the facepiece off while still 
 leaving the mouth-piece and noseclip in place. This gave pro- 
 tection to the lungs, but exposed the eyes, and as mustard gas 
 affects the eyes very readily this alone led to thousands of casu- 
 alties. There was another interesting side to this situation. The 
 malingerer who wanted to get out of the front line and was will- 
 ing to take any action, however cowardly, to achieve that end, 
 deliberately removed the facepiece and thus suffered gassing of 
 the eyes. The effect of mustard gas soon became so well known 
 that the malingerer knew gassing of the eyes never resulted in 
 death or permanent loss of sight. With the new type of 
 American mask, the protection of eyes and lungs depends solely 
 upon the fit around the face and no such playing with the mask 
 can be done. 
 
 "Without going into further details in regard to masks it is 
 
412 CHEMICAL WARFARE 
 
 sufficient to state that at the end the Americans had produced a 
 mask thoroughly comfortable, giving complete protection against 
 gases and smoke clouds, and one that was easy to manufacture on 
 the huge scale (fifty to seventy-five thousand per day) which was 
 necessary to provide masks for an army of three to four million 
 men in the field. 
 
 Protection in War is Relative Only 
 
 Napoleon is credited with saying ''In order to make an 
 omelet, it is necessary to break some eggs.'' Every student of 
 war realizes that casualties cannot be avoided in battle and yet 
 one American Staff Officer went so far as to refuse to use gas 
 offensively unless the Chemical Warfare Service could absolutely 
 guarantee that not a single American casualty could occur under 
 any circumstances. This same idea early got into the heads of 
 the laboratory workers on masks. They seemed to feel that if a 
 single gas casualty occurred through failure of the mask, their 
 work would be a failure or at least they would be open to severe 
 criticism. Accordingly efforts were made to perfect masks and 
 to perfect protection regardless of the discomfort imposed upon 
 the wearer of the mask. This idea was very difficult to eradicate. 
 The laboratory worker who accustoms himself to experiment with 
 a particular thing forgets that he develops an ability to endure 
 discomfort, that is not possible of attainment by the ordinary 
 man in the time available for his training. 
 
 Furthermore, if the need for such training can be avoided it 
 is of course highly desirable. This applies to the mouth-piece of 
 the British respirator; to elastics that cause undue discomfort 
 to the face ; to the noseclip and to the large boxes that cause too 
 great resistance to breathing. 
 
 It may be taken as a general rule that when protection 
 requires so much effort or becomes so much of a burden that the 
 average man cannot or will not endure it, it is high time to find 
 out what the average man will stand and then provide it even 
 if some casualties result. Protection in battle is always relative. 
 A man who cannot balance protection against legitimate risk has 
 no business passing on arms, equipment or tactics to be used in 
 battle. 
 
DEFENSE AGAINST GAS 413 
 
 Training 
 
 Bitter experience taught the Allies as well as the Americans 
 that no matter how efficient the gas mask and other defensive 
 appliances, they would not take the place of thorough and con- 
 stant training. One of the greatest difficulties at first was to get 
 American troops to realize that a thing as invisible as gas, with in 
 many cases no offensive smell and producing no immediate dis- 
 comfort, could be deadly. Nothing but constant drill and con- 
 stant reiteration of these dangers could get this fact impressed 
 on them. Indeed it never was impressed sufficiently in any of 
 the earlier divisions of American troops in the line to prevent 
 their taking such chances that each division suffered heavy loss 
 on one or more occasions from gas attacks. 
 
 A great deal of emphasis had been placed by the English 
 upon the adjustment of the mask in the shortest possible time, 
 this time having been officially set at six seconds after the alarm. 
 The Americans in adopting the mask in toto naturally had to 
 adopt the rules for adjusting it and wearing it. Experience, how- 
 ever, taught them in a few months that the effort to attain too 
 great speed was dangerous. It tended to rattle the soldier and 
 to result in poor adjustment of the mask, both of which led to 
 causalties. Accordingly in the latest instructions for defense 
 against gas all reference to six seconds was eliminated and 
 emphasis placed on the necessity of accurate adjustment of 
 the mask. Inasmuch as any -man, practically without effort or 
 previous drill, can hold his breath for twenty seconds, the need 
 for great speed in adjusting the mask is not apparent. 
 
 Holding the Breath 
 
 The first regulations and those in general use up to near 
 the close of hostilities, prescribed that the soldier should hold 
 his breath and adjust his mask. It seemed impossible to 
 overcome the natural inference that ''holding the breath" 
 meant first the drawing of a full breath. This was obviously 
 highly dangerous if gas were actually present before the 
 alarm was heard, as was often the case with projector and 
 artillery gas shell attacks. The change was then made to 
 
414 CHEMICAL WARFARE 
 
 the phrase '*Stop Breathing and Stay Stopped until the Mask 
 is Carefully and Accurately Adjusted/' 
 
 Psychology in Training 
 
 While the importance of impressing upon the soldier the 
 danger of gas was early appreciated it was deemed necessary 
 not to make him unduly afraid of the gas. However, as gas 
 defense training in our Army got a big start over gas offense 
 training, this became a matter of very great importance. In 
 fact, due to a variety of causes, training in the offensive use 
 of gas was not available for any troops until after their arrival 
 in France. This resulted in officers and men looking upon 
 the gas game, so far as they were individually concerned, as 
 one of defense only. Accordingly after their arrival in France 
 it became verj^ difficult not only to get some of our officers 
 to take up the offensive use of gas but even to get them to 
 permit its use along the front they commanded. 
 
 Notwithstanding all the care taken in training Americans 
 in gas defense there arose an undue fear of the gas that had 
 to be overcome in order to get our troops to attack close 
 enough to their own gas to make it effective. This applied 
 to the use of gas by artillery as well as to its use by gas troops. 
 However, it should be said that in every instance where gas was 
 once used on an American front all officers in the Division, 
 or other unit, affected by it were always thereafter strongly 
 in favor of it. 
 
 German Problems in Gas Training 
 
 The Germans also had serious troubles of their own over 
 the psychology of gas training. As stated elsewhere they 
 were using mustard gas nearly eleven months before the Allies 
 began using it. During that time, for purposes of morale, if 
 not sheer boastfulness, the Germans told their men that mus- 
 tard gas could not be made by the Allies ; that it was by far 
 the worst thing the war had produced— and in that statement 
 they were correct— and that they would win the war with 
 it — in which statement they were far from correct. When the 
 Allies began sending it back to them they had to reverse their 
 
DEFENSE AGAINST GAS 415 
 
 teachings and tell their men that mustard gas was no worse 
 than anything else, that they need not be afraid of it and that 
 their masks and other protective appliances gave full protec- 
 tion against it. They thus had a problem in psychology which 
 they never succeeded in fully solving. Indeed there is no 
 question but that the growing fear of gas in the minds of the 
 German is one of the reasons that prompted him to his early 
 capitulation. 
 
 ^v Gas at Night 
 
 In the early dayb it was very difficult to get officers to 
 realize the absolute necessity of night drill in the adjustment 
 of the mask. For various reasons, including surprise, gas 
 attacks were probably eighty to ninety per cent of the time 
 carried out at night. Under such conditions confusion in the 
 adjustment of the mask is inevitable without a great deal of 
 practice before hand, especially for duty in trenches with 
 narrow spaces and sharp projecting corners. There are numer- 
 ous instances of men waking up .and getting excited, who not 
 only gassed themselves, but in their mad efforts to find their 
 masks, or to escape from the gas, knocked others down, dis- 
 arranging their masks and causing the gassing of from one 
 to three or four additional men. The confusion inherent in 
 any gas attack was heightened in the latter stages of the war 
 by heavy shrapnel and high explosive bombardments that 
 accompanied nearly all projector and cloud gas attacks for that 
 very purpose. The bombardment was continued for three or 
 four hours to cause exhaustion and removal of the mask and 
 to prevent the removal of the gassed patients from the gassed 
 area. y 
 
 Y Detection of Gases 
 
 Efforts were made by the enemy and by all the Allies 
 throughout the war to invent a mechanical detector that would 
 show when gas was present in dangerous quantities. "While 
 scores, perhaps hundreds, of these were invented none proved 
 simple, quick, or certain enough in action to make their adop- 
 tion desirable. In every case it was necessary to rely on the 
 sense of smell. Thus it was that as the war wore on, more 
 
416 CHEMICAL WARFARE 
 
 and more attention was given to training officers and non- 
 commissioned officers to detect various kinds of gases in 
 dangerous quantities by the sense of smell. 
 
 In the American Gas Defense School for officers this was 
 done wholly by using captured German gases. This was 
 because certain gases have quite different smells, depending 
 upon the impurities in the gas and also upon the solvents 
 sometimes mixed with them. Thus the German mustard gas 
 has a mustard smell, while the Allies mustard gas, due to a 
 slight difference in the method of manufacture, has a very 
 perfect garlic odor. Not only must officers and men who 
 handle gas training know the smell of the various gases, but 
 they must know when the concentration of each is high 
 enough to be dangerous. This is not easy to learn because 
 the strength of the various gases in dangerous concentrations 
 varies through wide limits. Not only does the strength of 
 the gases vary and the sharpness of the odors accordingly, 
 but the mingling of poisonous gases with other gases from high 
 explosive and shrapnel tends .to obscure these odors and make 
 
 them more difficult of detection. 
 
 ■\ 
 
 Deceptive Gases 
 
 A great deal of thought was given toward the end of 
 the war to the subject of deceptive gases which could by 
 powerful or peculiar odors mask the dangerous gases. This 
 masking was to deceive the enemy when dangerous gases were 
 present or to admit an attack without masks while the enemy 
 was wearing his through thinking there was a dangerous gas 
 when as a matter of fact none existed. 
 
 In gas warfare, the German, as well as the Allies, was 
 exercising his ingenuity in devising new and startling methods 
 of making gas attacks. A well known trick with the German 
 was to fire gases for several days, particularly against green 
 troops, in concentrations so slight as to do no harm. When 
 he felt that he had lulled those troops to a sense of the ineffec- 
 tiveness of his gas, he sent over a deadly concentration. In 
 spite of the warning that this was what was happening, he 
 often achieved too great a success. Before the war closed, 
 
DEFENSE AGAINST GAS 417 
 
 however, the American was beginning to out-think and out-wit 
 the German in this method of warfare. 
 
 Mustard Gas Burns 
 
 With the advent of mustard gas which burned- the body, 
 a new and serious difficulty in protection arose. At first it 
 was thought mustard gas burned only when the liquid from 
 the bursting shell actually splashed on the clothing or skin. 
 This was unfortunately soon found to be not true. The gas 
 itself rapidly penetrates clothing and burns the skin even when 
 the concentration of the gas is very low. Probably the ma- 
 jority of burns from mustard gas arose from concentrations 
 of gas consisting of less than one part of gas to five hundred 
 thousand of air. Furthermore, the gas is fully fifty per cent 
 cumulative in its effects, that is, in extremely low concentra- 
 tions over a period of hours it will produce more than fifty 
 per cent the effect that a far higher concentration would 
 produce in a relatively shorter time. 
 
 The Allies were not long in discovering that oilcloth 
 afforded very complete protection against mustard gas. The 
 ordinary oilcloth, however, was too thick, too hot and too 
 heavy for general use. Experiments soon showed that cloth 
 thoroughly impregnated with boiled linseed oil would give 
 protection. In order to make this protection more perfect 
 a certain amount of paraffin was added. All this made the 
 clothing air-tight, rather stiff and always uncomfortable. Not- 
 withstanding these discomforts, hundreds of thousands of 
 oiled suits, and as many pairs of oiled gloves were made and 
 issued to artillery troops, and to troops especially charged 
 with handling mustard gas shells, or to those employed in 
 destroying mustard gas in shell holes by spreading chloride 
 of lime over them. 
 
 The importance of protection against mustard gas burns 
 led to extensive researches being made with a view to finding 
 a cloth which would be comfortable and porous and while 
 stopping mustard gas would yet be sufficiently durable and 
 comfortable to be issued to infantry troops as well as to 
 artillery and other special troops. This, it is understood, had 
 
418 CHEMICAL WARFARE 
 
 been achieved, just prior to the Armistice. Still more desir- 
 able would be the discovery of a chemical substance which 
 could be applied to all uniforms and Army clothing and thus 
 protect the regulation clothing against the penetration of 
 mustard gas, and thereby avoid carrying extra clothing for 
 that special purpose. 
 
 Protecting Troops by Moving Them From Infected Areas 
 
 As soon as it was fully realized that mustard gas persisted 
 for several days it was decided to run complete reliefs of 
 men into and out of areas that had been heavily shelled with 
 mustard gas, or better still, where practicable, to completely 
 evacuate the area. Inasmuch as the gas is dangerous to 
 friend and foe alike, this method was comparatively safe and 
 was used to a very considerable extent. With the warfare 
 of movement that existed over most of the active front 
 throughout the season of 1918, this moving of troops out of 
 infected areas became highly important and, when skillfully 
 done, often resulted in a great saving of troops and at the same 
 time prevented the enemy from receiving any particular tac- 
 tical advantage from his mustard gas attacks. 
 
 There was one very excellent example of this a few miles 
 to the northwest of Chateau-Thierry prior to the counter- 
 offensive of July 18, 1918. At that time the Germans heavily 
 shelled with mustard gas four or five small woods and two 
 or three villages. It was necessary for the men to stay in 
 these woods during the day, as they afforded the only protec- 
 tion obtainable from machine guns, shrapnel and high 
 explosive. At the time this occurred American gas officers 
 generally understood the necessity of getting troops out of 
 a mustard gas infected area. Accordingly all began searching 
 for places safe from the mustard gas. In one particular in- 
 stance the gas officer of a regiment discovered that a portion 
 of the woods his men were in was free from the gas, and 
 the regimental commander, promptly following his advice, 
 moved his troops into the free area. As a result of this prompt 
 action the regiment had only four light gas casualties, although 
 all told there were several hundred mustard gas casualties 
 
DEFENSE AGAINST GAS 419 
 
 in this attack, the number per thousand generally being from 
 ten to twenty times that of the thousand men just mentioned. 
 
 \ 
 
 Mixing Poisonous Gases 
 
 On this as well as other occasions the Germans fired some 
 diphosgene and Blue Cross (Sneezing gas), as well as mustard 
 gas. This added to the difficulty of determining areas free 
 from the latter. In the future such mixing of poisonous gases 
 may always be expected and, in addition, gases which have 
 no value other than that of masking the poisonous ones will 
 be fired. While with practically all gases except mustard gas 
 a man is comparatively safe while breathing a concentration 
 very noticeable to the sense of smell, the only safe rule with 
 mustard gas is to consider as dangerous any concentration 
 that can be smelled. 
 
 For the reason that this gas persists longer in calm areas, 
 woods are always to be avoided, where practicable, and also, 
 since all gases, being heavier than air, tend to roll into depres- 
 sions and valleys, they should be avoided. There have 
 been a number of authentic cases where batteries in hollows 
 or valleys suffered severely from mustard gas, while troops 
 on nearby knolls or ridges were comparatively free, though 
 the difference in the amount of shelling of the two places 
 vv'as not noticeable. 
 
 Of great importance with all gases is the posting of a 
 sufficient number of sentries around men sleeping within the 
 range of gas shell. The worst projector gas attack against 
 tlie Americans was one where the projectors were landed 
 among a group of dugouts containing men asleep without 
 sentries. The result was a very heavy casualty list, coupled 
 with a high death rate, the men being gassed in their sleep 
 before they were awakened. 
 
 \), Destruction op Mustard Gas 
 
 Prior to the introduction of mustard gas all that was 
 necessary to get rid of gas was to thoroughly ventilate the 
 spot. Thus in trenches and dugouts, fires were found to be 
 very efficient, simply because they produced a circulation of 
 
420 CHEMICAL WARFARE 
 
 air. In the early days, among the British, the Ayrton fan, 
 a sort of canvas scoop, was used to throw the gas out of the 
 trenches. While this was taken up in the American Service, 
 it did not become very important, since it was found that, 
 under ordinary atmospheric conditions, natural ventilation 
 soon carried the gas out of the trench proper, while fires in 
 dugouts were far more efficient than the fans. Likewise the 
 Ayrton fan smacked too much of trench warfare which had 
 reached a condition of *' stalemate" — a condition that never 
 appealed to the Americans and a condition that it is hoped 
 never will. 
 
 With mustard gas, however, conditions were entirely 
 changed. This liquid having a very high boiling point and 
 evaporating very slowly, remains for days in the earth and 
 on vegetation and other material sprinkled with it. This was 
 particularly true in shell holes where the force of the explosion 
 drove the gas into the earth around the broken edges of the 
 hole. While many substances were experimented with, that 
 which proved best and most practical under all conditions, 
 v/as chloride of lime. This was used to sprinkle in shell holes, 
 en floors of dugouts and any other places where the liquid 
 might be splashed from bursting shells. It was also found 
 very desirable to have a small box of this at the entrance to 
 each dugout, so that a person who had been exposed to mustard 
 gas could thoroughly coat his shoes with it and thus kill tlie 
 mustard gas that collected in the mud on the bottom and sides 
 of his shoes. 
 
 Carrying Mustard. Gas on Clothing 
 
 There are many instances where the occupants of dugouts 
 were gassed from the gas on the shoes and clothing of men 
 entering the dugout. Not only Avere occupants of dugouts thus 
 gassed but a number of nurses and doctors were gassed while 
 working in closed rooms over patients suffering from mustard 
 gas poisoning. Even under the conditions of warfare existing 
 where the Americans were generally in action, the quantity 
 of chloride of lime required amounted to several hundred tons 
 per month which had to be shipped from the United States. 
 
DEFENSE AGAINST GAS 421 
 
 Chloride of lime was also very convenient to have at hand 
 around shell dumps for the purpose of covering up leaky shells, 
 though rules for handling mustard gas shells usually prescribed 
 that they be fired and where that was not practicable to bury 
 them at least five feet under the surface of the ground. This 
 depth was not so much for the purpose of getting rid of the 
 gas as it was to get the shell so deep into the ground that it 
 would not be a danger in any cultivation that might later 
 take place. 
 
 Mustard Gas in Cold Weather "^ 
 
 Much was learned toward the end of the war about ways 
 of getting through or around areas infected with mustard gas. 
 For instance, if mustard gas be fired when the weather is in 
 the neighborhood of freezing or somewhat below, it will remain 
 on the ground at night with so little evaporation as not to 
 be dangerous. The same will be true during the day time 
 if the weather is cloudy as well as cold. If, however, the days 
 are bright and the niglits cold, mustard gassed areas can be 
 safely crossed by troops at night provided care is taken in 
 brush and buslies to protect the feet and clothing from the 
 liquid splashed on bushes. If the sun comes out warm in 
 the morning such areas may be quite dangerous for three to 
 four hours following sun-up and indeed for the greater part 
 of the day. Quite a large number of casualties were ascribed 
 to this fact in the heavy attack on the British front west 
 of Cambrai just prior to the great German drive against 
 Amiens, March 21, 1918. 
 
 Degassing Units \^ 
 
 Since mustard gas has a greatly delayed action it was 
 found that if men who had been exposed to it could be given 
 a thorougli bath with soap and water within a half hour or 
 even a full hour, the mustard gas burns would be prevented 
 or very greatly reduced in severity. Accordingly degassing 
 units were developed consisting essentially of a 5 ton truck 
 with a 1200 gallon water tank, fitted with an instantaneous 
 heater and piping to connect it to portable shower baths. 
 
422 CHEMICAL WARFARE 
 
 Another truck was kept loaded with extra suits of undercloth- 
 ing and uniforms. These degassing units were to be provided 
 at the rate of two per division. Then, in the event of a mus- 
 tard gas attack anywhere in the division, one of these units 
 would be rushed to that vicinity and the men brought out 
 of the line and given a bath and change of clothing as soon 
 as possible. At the same time they were given a drink of 
 bicarbonate of soda water and their eyes, ears, mouth and 
 nasal passages washed with the same. 
 
 Protecting Food from Mustard Gas \ 
 
 It was very early learned that mustard gas, or minute 
 particles of the liquid gas settling on food, caused the stomach 
 to be burned if the food were eaten, just as the eyes, lungs 
 and skin of the body are burned from gas in the air. This 
 made it necessary then to see that all food liable to exposure 
 to mustard gas attacks was protected, and tarred paper for 
 box linings or tops was found by the Gas Service to furnish 
 one of the cheapest and most available means of doing this. 
 
 Alarm Signals \ 
 
 Numerous, indeed, were the devices invented at one time 
 or another with which to sound gas alarms. The English 
 early devised the Strombos horn, a sort of trumpet operated 
 by compressed air contained in cylinders carried for that 
 purpose. Its note is penetrating and can be heard, under 
 good conditions, for three or four miles. When cloud gas 
 attacks, which occurred only at intervals of two to four 
 months, were the only gas attacks to be feared, it was easy 
 enough to provide for alarm signals by methods as cumbersome 
 and as technically delicate as the Strombos horn. 
 
 With the advent of shell gas in general, and mustard gas 
 in particular, the number of gas attacks increased enormously. 
 This made it not only impossible, but inadvisable also, to 
 furnish sufficient Strombos horns for all gas alarms, as gas 
 shell attacks are comparatively local. In such cases, if the 
 Strombos horn is used to give warning, it causes troops who 
 are long distances out of the area attacked to take precautions 
 
DEFENSE AGAINST GAS 423 
 
 against gas with consequent interference with their work or 
 fighting. 
 
 To meet these local conditions metal shell cases were first 
 hung up and the alarm sounded on them. Later steel triangles 
 were used in the same way. At a still later date the large 
 policeman's rattle, well known in Europe, was adopted and 
 following that the Klaxon horn. As the warfare of movement 
 developed the portability of alarm apparatus became of prime 
 importance. For those reasons the Klaxon horn and the police 
 rattle were having a race for popularity when the Armistice 
 was signed. 
 
 A recent gas alarm invention that gives promise is a small 
 siren-like whistle fired into the air like a bomb. It is fitted 
 with a parachute which keeps it from falling too rapidly when 
 the bomb explodes and sets it free. Its tone is said to be very 
 penetrating and to be quite effective over an ample area. 
 Since future gas alarm signals must be efficient and must be 
 portable, the lighter and more compact they can be made the 
 better; hence the desirability of parachute whistles or similar 
 small handy alarms. 
 
 IssuESTG New Masks 
 
 One of the problems that remained unsolved at the end 
 of the war was how to determine when to issue new boxes, or 
 canisters, for masks. One of the first questions asked by the 
 soldier is how long his mask is good in gas, and how long 
 when worn in drill where there is no gas. This information 
 is of course decidedly important. Obviously, however, it is 
 impossible to tell how long a canister will last in a gas attack, 
 unless the concentration of gas is known — that is, the life 
 of the box is longer or shorter as the concentration of gas 
 is weak or heavy. 
 
 A realization of this need led mask designers to work very 
 hard, long before the necessity for comfort in a mask was as 
 fully realized as it was at the end of the war, to increase 
 the length of life of the canister. To get longer life they 
 increased the chemicals and this in turn increased the breath- 
 ing resistance, thereby adding to the discomfort of the soldier 
 
424 CHEMICAL WARFARE 
 
 when wearing the mask. Finally, however, it was found that 
 in the concentration of gas encountered on an average in 
 the field, the life of the comparatively small American boxes 
 was sufficient to last from fifty to one hundred hours, which 
 is longer than any gas attack or at least gives time to get 
 out of the gassed area. 
 
 The British early appreciated the necessity of knowing 
 when boxes should be replaced. They accordingly devised 
 the scheme of furnishing with each mask a very small booklet 
 tied to the carrying case in which the soldier could not only 
 enter a complete statement of the time he had worn the mask 
 but also the statement as to whether it was in gas or for 
 drill purposes only. The soldier was then taught that if he 
 had worn the mask, say for forty hours, he should get a new 
 box. But the scheme didn't work. In fact, it was one of 
 those things which foresight might have shown wouldn't work. 
 Indeed, any man who in the hell of battle can keep such a 
 record completely, should be at once awarded a Distinguished 
 Service Medal. 
 
 As gas warfare developed not only were all kinds of gas 
 shells sent over in a bunch but they were accompanied by 
 high explosive, shrapnel and anything else in the way of 
 trouble that the enemy possessed. A man near the front line, 
 under those conditions, had all he could do and frequently 
 more than he could do, to get his mask on and keep it on 
 while doing his bit. Consequently he had no time, even if 
 he had the inclination, to record how long he had the mask 
 in the various gases. 
 
 In this connection, after the Armistice was signed we in 
 the field were requested to obtain for experimental purposes 
 10,000 canisters that had been used in battle. Each was to 
 be labeled with the length of time it had been worn in or 
 out of gas, and if in gas, the name of each gas and the time 
 the mask was worn in it. This request is just a sample of 
 what is asked by those who do not realize field conditions. 
 One trip to the front would have convinced the one making 
 the request of the utter impossibility of complying with it, 
 for really no man knows how long he wears a mask in gas. 
 With gas as common and as difficult to detect (when inter- 
 
DEFENSE AGAINST GAS 425 
 
 mingled with high explosive gases and other smells of the 
 battle field) as it was at the end of the war, each man wore 
 the mask just as long as he could, simply as a matter of 
 precaution. 
 
 Before hostilities ceased we were trying out a method 
 of calling in say fifty canisters per division once a week for 
 test in the laboratory. If the tests showed the life of the 
 canisters to be short new canisters would be issued. While 
 we did not have opportunity to try out this plan, it gave 
 promise of being the best that could be done. With gas 
 becoming an every day affair, the only other alternative would 
 seem to be to make issues of new boxes at stated intervals. 
 On the other hand there are no definite records of casualties 
 occurring from the exhaustion of the chemicals in the box. 
 Undoubtedly some did occur, but they were very, very few. 
 In nearly all cases the masks got injured, or the box became 
 rusted through before the chemicals gave out. 
 
 Tonnage and Number of Masks Required 
 
 It will probably be a shock to most people to learn that 
 with more than two million men in France we required nearly 
 1500 tons of gas material per month. This tonnage was increas- 
 ing, rather than decreasing, to cover protective suits, gloves, 
 pastes, and chloride of lime, as well as masks. The British type 
 respirator was estimated to last from four to six months. The 
 active part of the war, in which the Americans took part, 
 was too short to determine whether this was correct or not. 
 The indications were, however, that it was about right, con- 
 sidering rest periods and fighting periods. 
 
 With the new American mask, with its much stronger and 
 stiffer face material, the chances are that the life will be con- 
 siderably increased although the more constant use of the 
 mask will probably offset its greater durability. A longer 
 life of mask would of course be a decided advantage as it 
 would not only reduce tonnage, but would reduce manufac- 
 turing and distribution as well. The estimates on which we 
 were working at the end looked forward to requiring from 
 the United States about one-third pound per man per day for 
 
426 CHEMICAL WARFARE 
 
 all troops in France, in order to keep them supplied with gas 
 defense material and with the gases used offensively by gas 
 troops. All gas shell, hand grenades, etc., used by other than 
 gas troops required tonnage in addition to the above. 
 
 Summing Up 
 
 In summing up then, it is noted that there are several 
 important things in defense against gas. First, the mask which 
 protects the eyes and the- lungs. Second, the training that 
 teaches the man how to utilize to best advantage the means 
 of protection at his disposal, whether he be alone or among 
 others. Third, protective clothing that protects hands and 
 feet and the skin in general. Fourth, a knowledge of gases 
 and their tactical use that will enable commanders, whenever 
 possible, to move men out of gas-infected areas. Fifth, train- 
 ing in the off eiiiiive use of gas, as well as in defensive methods, 
 to teach the man that gas has no uncanny power and that it is 
 simply one element of war that must be reckoned with, thus 
 preventing stampedes when there is really no danger. 
 
 While these are the salient points in defense against gas, 
 above them and beyond them lies the vigorous offensive use 
 of gas. This involves not only the research, development and 
 manufacture of necessary gases in peace time, but also the 
 necessary training to enable our nation to hurl upon the enemy 
 on the field of battle chemical warfare materials in quantities 
 he cannot hope to attain. 
 
CHAPTER XXV 
 PEACE TIME USES OF GAS 
 
 ''Peace hath her victories no less renowned than war/' 
 Thus runs the old proverb. In ancient times war profited by 
 peace far more than peace profited by war if indeed the latter 
 ever actually occurred. The implements developed for the 
 chase in peace became the weapons of war. This was true of 
 David's sling shot, of the spear and of the bow. Even powder 
 itself was probably intended and used for scores of years for 
 celebrations and other peaceful events. 
 
 The World War reversed this story, especially in its later 
 phases. The greater part of the war was fought with imple- 
 ments and machines prepared in peace either for war or for 
 peaceful purposes. Such implements were the aeroplane, sub- 
 marine, truck, automobile and gasoline motors in general. The 
 first gas attack, which was simply an adaptation of the peace- 
 time use of the chemical chlorine, inaugurated the change. Gas 
 was so new and instantlj^ recognized as so powerful that the 
 best brains in research among all the first-class powers were 
 put to work to develop other gases and other means of project- 
 ing them upon the enemy. The result was that in the short 
 space of three and one-half years a number of substances- were 
 discovered, or experimented with anew, that are aiding to-day 
 and will continue to aid in the future in the peaceful life of 
 every nation. 
 
 Chlorine is even more valuable than ever as a disinfectant 
 and water purifier. It is the greatest bleaching material in the 
 world, and has innumerable other uses in the laboratory. Chlo- 
 ropicrin, cyanogen chloride and cyanogen bromide are found to 
 be very well adapted to the killing of weevil and other similar 
 insect destroyers of grain. Hydrocyanic acid gas is the great- 
 est destroyer to-day of insect pests that otherwise would ruin 
 
 427 
 
428 
 
 CHEMICAL WARFARE 
 
 the beautiful orange and lemon groves of California and the 
 South. 
 
 Phosgene, so extensively used in the war both in cloud gas 
 
 SALT PRODUCTS 
 
 IN WAR AND PEACE TIME INDUSTRIES 
 
 f 
 
 ■► '-* 
 
 saPt 
 
 CHLORINE 
 
 :WAR GAS 
 WATER PUPIFICATI'^N 
 
 i 
 
 CAUSTl^- SODA 
 
 1 
 
 CHLORIDE OF LIME 
 
 iBLEACttlNG PCWDER; 
 .DISINFECTANT 
 
 X-"' 
 ^J^ 
 
 CHf.OROFORM 
 
 1 
 
 M EXILIC 
 SODIUM 
 
 SOAPS 
 
 CHLORACETIC 
 ACID 
 
 PH050ENE SODIUM 
 CYANIDE 
 
 ■,..SiN(-CCTANT 
 
 i 
 
 iNDIGO 
 
 J 
 
 SODIUM 
 
 5ULPHOCARBOLATE 
 
 MECiCIN AL 
 
 SODIUM 
 SALICYLATE 
 
 MECiClNAL. 
 
 YLL.LOW WOOL GREEN CRYSTACViOlE- 
 
 ■*"' DYE iDYE, •«»»««<«* DYE. 
 
 CHLORA- CYANOGEN CHLORIDE 
 
 CETOPHENONE • --/ap Oas 
 
 WAR OAS 
 
 Fig. 120. 
 
 and in shell, is finding an ever increasing use in the making of 
 brilliant dyes — pinks, greens, blues and violets. On account of 
 its cheapness and simplicity of manufacture, it has great pos- 
 sibilities in the destruction of rodents such as rats around 
 
PEACE TIME USES OF GAS 429 
 
 wharves, warehouses and similar places that are inaccessible 
 to any other means of reaching those pests. Since phosgene 
 is highly corrosive of steel, iron, copper and brass, it cannot 
 be used successfully in places where those metals are present. 
 
 Instead of phosgene for killing rodents and the like in store- 
 houses and warehouses, cyanogen bromide has been developed. 
 This is a solid and can be burned like an ordinary sulphur 
 candle. It is much safer for the purpose of fumigating rooms 
 and buildings than is hydrocyanic acid gas when so used. This 
 is for the reason that cyanogen bromide is an excellent lachry- 
 mator in quantities too minute to cause any injury to the 
 lungs. It will thus give warning to anyone attempting to enter 
 a place where some of the gas may still linger. 
 
 Among tear gases, the new chloracetophenone, a solid, is 
 perhaps the greatest of all. When driven off by heat it first 
 appears as a light bluish colored cloud. This cloud is instantly 
 so irritating to the eyes that within a second anyone in the 
 path of the cloud is temporarily blinded. It causes considerable 
 smarting and very profuse tears which even in the smallest 
 amount continue for two to five minutes. In greater quan- 
 tities it would continue longer. So far as can be ascertained, 
 it is absolutely harmless so far as any permanent injuries are 
 concerned. 
 
 Considering that it is instantly effective, that minute quan- 
 tities are unbearable to the eyes, that it can be put in hand 
 grenades or other small containers and driven off by a heat- 
 ing mixture which will not ignite even a pile of papers, and 
 that it needs no explosion to burst the grenade (all that is used 
 is a light cap, set off by the action of the spring, sufficient to 
 ignite the burning charge), the future will see every police 
 department in the land outfitted with chloracetophenone or 
 other similar grenades. Every sheriff's office, every jail and 
 every penitentiary will have a supply of them. No jail break- 
 ing, no lynching, no rioting can succeed where these grenades 
 are available. Huge crowds can be set to weeping instantly 
 so that no man can see and no mob will continue once it is 
 blinded with irritating tears. More than that, it is an ex- 
 tremely difficult gas to keep out of masks, ordinary masks of 
 the "World War being entirely useless against it. 
 
430 CHEMICAL WARFARE 
 
 The same is true of diphenylaminechlorarsine. This is not 
 a tear gas but it is extraordinarily irritating to the lungs, throat 
 and nose, where it causes pains and burning sensations, and in 
 higher concentrations vomiting. It is hardly poisonous at all 
 so that it is extremely difficult to get enough to cause danger 
 to life. This is mentioned because of its possible use for the 
 protection of bank vaults, safes, and strong rooms generally. 
 
 There are many other gases that can be used for this same 
 purpose. It is presumed that gases that are not powerful 
 enough to kill are the ones desired, and there are half a dozen 
 at least that can be so used. If desired deadly gases can just 
 as readily be used. Already a number of inventors are at work 
 on the problem, with some plans practically completely worked 
 out and models made. 
 
 It has been suggested that one of these gases could be 
 used by trappers in trapping wild animals. Hydrocyanic acid 
 gas may be so used. It acts quickly and is very rapidly dis- 
 sipated. An animal exposed to the fumes would die quickly 
 and the trap be safe to approach within two minutes after it 
 was sprung. It is said that the loss from animals working 
 their way out of traps by one means or another is nearly 20 
 per cent. More than this, it would meet the objections of the 
 S. P. C. A. in that the animal would not suffer from having 
 its limbs torn and lacerated by the trap. 
 
 Attempts are being made to attack the locust of the Philip- 
 pines and the far west and the boll weevil of the cotton states 
 of the South. So far these tests have not proven more success- 
 ful than other methods, but inasmuch as the number of gases 
 available for trial are so great and the value of success of so 
 m.uch importance, this research should be continued on a large 
 scale to definitely determine whether poisonous gas can be 
 used to eradicate these pests — especially the boll weevil. 
 
 As an interesting application of war materials to peaceful 
 uses, we may consider the case of cellulose-acetate, known dur- 
 ing the war as ''aeroplane dope," the material used to coat the 
 linen covering aeroplane wings. With a little further manipu- 
 lation, this cellulose-acetate, or aeroplane dope, becomes arti- 
 ficial silk — a silk that to-day is generally equal to the best 
 natural silk — and which promises in the future to become a 
 
PEACE TIME USES OF GAS 
 
 431 
 
 standard product better in every way than that from the silk 
 worm. 
 
 These few examples of the peacetime value of gas are 
 
 COAL PRODUCTS 
 
 IN WAR AND PEACE TIME INDUSTRIES 
 
 
 I 
 
 FUEL, 
 
 ^ 
 
 CARBOLIC Picmc 
 ACID , ACID 
 
 'mcoicinal 0- high explo 
 disinfcctantsive: &■ dye: 
 
 4^ 
 
 BENZENE 
 
 
 PONCEAU CHLORPICRIN 
 
 DYE: WAR GASi 
 
 BROMBENZYLCYANIDE 
 
 'WAR GAS 
 
 NITROBENZENE 
 
 4^ 
 
 h r 
 
 IPH^L 
 
 DIPHeriTL- 
 CHLORARSINE 
 
 fWAR GAS; .,^ 
 
 BUTTER YELLOW 
 
 ■er%:l 
 
 ANILINE 
 
 ACET'^fitlDE 
 
 Fig. 121, 
 
 worthy of thought from another standpoint. Being so valu- 
 able, their use in peace will not be stopped. If they are thus 
 manufactured and used in peace, they will always be available 
 
432 CHEMICAL WARFARE 
 
 for use in war, and as the experience of the World War proved, 
 they certainly will be so used even should anybody be foolish 
 enough to try to abolish their use. As for this latter idea, the 
 world might as well recognize at once that half-way measures 
 in war simply invite disaster. 
 
 This chapter would not be complete without a brief state- 
 ment of the necessity of a thoroughly developed chemical in- 
 dustry in the United States as a vital national necessity if the' 
 United States is to have real preparedness for a future struggle. 
 As will be indicated a little later, no one branch of the chemical 
 industry can be allowed to go out of existence without endan- 
 gering some part of the scheme of preparedness. 
 
 Let us consider first the coal tar industry. Coal tar is a 
 by-product of coke ovens or the manufacture of artificial gas 
 from coal. The coal tar industry is of the utmost importance 
 because in the coal tars are the bases of nearly all of the 
 modern dyes, a large percentage of the modern medicines, most 
 of the modern high explosives, a large proportion of poisonous 
 gases, modern perfumes, and photographic materials. 
 
 A consideration of these titles alone shows how vital the 
 coal tar industry is. The coal tar as it comes to us as a by- 
 product is distilled, giving off at different temperatures a series 
 of compounds called crudes. Ten of these are of very great 
 importance. The first five are benzene, toluene, naphthalene, 
 anthracene and phenol (carbolic acid). The second group com- 
 prises xylene, methylanthracene, cresol, carbazol and phenan- 
 threne. 
 
 These, when treated with other chemicals, produce a series 
 of compounds called intermediates, of which there are some 300 
 now known. From" these intermediates by different steps are 
 produced either dyes, high explosives, poisonous gases, pharma- 
 ceuticals, perfumes or photographic materials. 
 
 We have all heard that Germany controlled the dye in- 
 dustry of the world prior to the World War. A little study 
 of the above brief statement of what is contained in the coal 
 tar industry along with dyes will show in a measure one of the 
 reasons why Germany felt that she could win a war against the 
 world. That she came so desperately close to winning that war 
 is proof of the soundness of her view. 
 
PEACE TIME USES OF GAS 433 
 
 In many of the processes are needed the heavy chemicals 
 such as chlorine, sulfuric acid, nitric acid, hydrochloric acid 
 and the like. The alcohol industry is also of very great im- 
 portance. Grain alcohol is used extensively in nearly all 
 research problems and in very great quantities in many com- 
 mercial processes such as the manufacture of artificial silk and 
 foi" gasolene engines in addition to its use in compounding medi- 
 cines. It is of very great importance to the Chemical War- 
 fare Service in that from grain alcohol is obtained ethylene 
 gas, one of the three essentials in the manufacture of mustard 
 gas. While this ethylene may be obtained from many sources, 
 the most available source, considering ease of transportation 
 and keeping qualities, is in the form of grain alcohol. 
 
 Allied to the chemical industries just mentioned is the 
 nitrate industry for making nitric acid from the nitrogen of 
 the air. Nitrates are used in many processes of chemical man- 
 ufacture and particularly in those for the production of smoke- 
 less powders. The fertilizer industry is of large importance 
 because it deals with phosphorus, white phosphorus being not 
 only one of the best smoke producing materials but a material 
 that is, as stated elsewhere, of great use against men through 
 its powerful burning qualities. 
 
 Another point not mentioned above in connection with 
 these industries is the training of chemists, chemical engineers 
 and the building up of plants for the manufacture of chemicals, 
 all of which are necessary sources of supply for wartime needs. 
 Chemists are needed in the field, in the laboratory and in man- 
 ufacturing plants. The greater their number, the more effi- 
 ciently can these materials be handled, and since chemicals 
 as such will probably cause more than 50 per cent of all cas- 
 ualties in future wars, their value is almost unlimited. 
 
 Instead of trying to ameliorate the ravages of war, let us 
 turn every endeavor towards abolishing all war, remembering 
 that the most scientific nations should be the most highly civi- 
 lized, and the ones most desirous of abolishing war. If those 
 nations will push every scientific development to the point 
 where by the aid of their scientific achievements they can over- 
 come any lesser scientific peoples, the end of war should be in 
 sight. 
 
434 CHEMICAL WARFARE 
 
 However, we can never be certain that war is abolished 
 until we convince at least a majority of the world that war 
 is disastrous to the conqueror as well as to the conquered, 
 and that any dispute can be settled peacefully if both parties 
 will meet on the common ground of justice and a square deal. 
 
CHAPTER XXVI 
 THE FUTURE OF CHEMICAL WARFARE 
 
 The pioneer, no matter what the line of endeavor, en- 
 Xiounters difficulties caused by his fellow-men just in proportion 
 as the thing pioneered promises results. If the promise be 
 small, the difficulties usually encountered are only those neces- 
 sary to make the venture a success. If, however, the results 
 promise to be great, and especially if the rewards to the 
 inventor and those working with him promise to be consider- 
 able, the difficulties thrown in the way of the venture become 
 greater and greater. Indeed whenever great results are 
 promised, envy is engendered in those in other lines whose 
 importance may be diminished, or who are so short-sighted 
 as to be always opposed to progress. 
 
 Chemical warfare has had, and is still having, its full share 
 of these difficulties. From the very day when chlorine, known 
 to the world as a benign substance highly useful in sanitation, 
 water purification, gold mining and bleaching was put into 
 use as a poisonous gas, chemical warfare has loomed larger 
 and larger as a factor to be considered in all future wars. 
 Chlorine was first used in the cylinders designed for shipping 
 it. These cylinders were poorly adapted for warfare, and 
 made methods of preparing gas attacks extremely laborious, 
 cumbersome and time-consuming. 
 
 It was not many months, however, until different gases 
 began to appear in large quantities in shells and bombs, while 
 the close of the war, 3% years later, saw the development 
 of gas in solid form whereby it could be carried with the 
 utmost safety under all conditions — a solid which could become 
 dangerous only when the heating mixture, that freed the gas, 
 was properly ignited. 
 
 While some of the chemicals developed for use in war prior 
 
 435 
 
436 CHEMICAL WARFARE 
 
 to the Armistice have been made known to the world, a number 
 or others have not. More than this, every nation of first class 
 importance has continued to pursue more or less energetically 
 studies into chemical warfare. These studies will continue, 
 and we must expect that new gases, new methods of turning 
 them loose, and new tactical uses will be developed. 
 
 Already it is clearly foreseen that these gases will be used 
 by every branch of the Army and the Navy. While chemicals 
 were not used by the Air Service in the last war, it was even 
 then realized that there was no material reason why they 
 should not have been so used". That they will be used in the 
 future by the Air Service, and probably on a large scale, is 
 certain. The Navy, too, will use gases, and probably on a 
 considerable scale. Thus chemical materials as such become 
 the most universal of all weapons of war. 
 
 Some of the poisonous gases are so powerful in minute 
 quantities and evaporate so slowly that their liberation does 
 not produce sufficient condensation to cause a cloud. Conse- 
 quently, we have gases that cannot be seen. Others form 
 clouds by themselves, such, for instance, as the toxic smoke 
 candle, where the solid is driven off by heating, while still 
 others cause clouds of condensed vapor. This brings the dis- 
 cussion into the realm of ordinary smokes that have no 
 irritating and no poisonous effects. 
 
 These smokes are extremely valuable where the purpose is 
 to form a screen, whether it be to hide the advance of troops 
 or to cut off the view of observers. These smokes are equally 
 useful on land and on sea. So great is the decrease in efficiency 
 of the rifle or machine gun, and of artillery even when firing 
 at troops that cannot be seen, that smoke for screening pur- 
 poses will be used on every future field of battle. When firing 
 •through a screen of smoke, a man has certainly less than 
 one-quarter the chance to hit his target that he would have 
 were the target in plain view. Since smoke clouds may or 
 may not be poisonous and since smoke will be used in every 
 battle, there is opened up an unlimited field for the exercise 
 of ingenuity in making these smoke clouds poisonous or non- 
 poisonous at will. It also opens up an unlimited field for the 
 well-trained chemical warfare officer who can tell in any smoke 
 
THE FUTURE OF CHEMICAL WARFARE 437 
 
 cloud whether gas be present and whether, if present, it is in 
 sufficient concentration to be dangerous. 
 
 At the risk of repetition, it is again stated that there is no 
 gas that will kill or even permanently injure in any quantity 
 that cannot be detected. For every gas, there is a certain 
 minimum amount in each cubic foot of air that is necessary 
 to cause any injury. In nearly all ga,ses^thisjninimum amount | 
 is sufficient to be readily noticeable by a trained chemical 
 warfare officer through the sense of smell. 
 
 It would be idle to attempt to enumerate the ways and 
 means by which chemicals will be used in the future. In fact, 
 one can hardly conceive of a situation where gas or smoke will / 
 not be employed, for these materials may be liquids or solids 
 that either automatically, upon exposure to the air, turn into 
 gas, or which are pulverized by high explosive, or driven off 
 by heat. This varied character of the materials enables them 
 to be used in every sort of artillery shell, bomb or other con- 
 tainer carried to the field of battle. 
 
 SoUie of the gases ^re extremely powerful as irritants to 
 the nose and throat in very minute quantities, while at the 
 same time being highly poisonous in high concentrations. 
 Diphenylchloroarsine, used extensively by the Germans in high 
 explosive shell, is more poisonous than phosgene, the most 
 deadly gas in general use in the past war. In addition, it 
 has the quality of causing an intolerable burning sensation 
 in the nose, throat, and lungs, in extremely minute quantities. 
 This material can be kept out of masks only by filters, whereas 
 true gases are taken out by charcoal and chemical granules. 
 
 There is still another quality which helps make chemical 
 warfare the most powerful weapon of war. Gas is the orfly 
 substance used in war which can be counted on to do its work y 
 as efficiently at night as in the daytime. Indeed, it is often 
 more^ effective a-t night than in^Uie^^time, because the man 
 who goes to sleep without his mask on, who is careless, who 
 loses his mask, or who becomes excited in the darkness of 
 night, becomes a casualty, and the past war showed that these 
 casualties were decidedly numerous even when the troops knew 
 almost to the minute the time the gas would arrive. 
 
 Accordingly, chemical warfare is an agency that must 
 
438. CHEMICAL WARFARE 
 
 not only be reckoned with by every civilized nation in the 
 future, but is one which civilized nations should not hesitate 
 to use. When properly safe-guarded with masks and other 
 safety devices, it gives to the most scientific and most ingenious 
 people a great advantage over the less scientific and less 
 ingenious. Then why should the United States or any other 
 highly civilized country consider giving up chemical warfare? 
 To say that its use against savages is not a fair method of 
 I fighting, because the savages are not equipped with it, is 
 I arrant nonsense. No nation considers such things today. If 
 they had, our American troops, when fighting the Moros in 
 the Philippine Islands, would have had to wear the breechclout 
 and use only swords and spears. 
 
 Notwithstanding the opposition of certain people who, 
 through ignorance or for other reasons, have fought it, 
 chemical warfare has come to stay, and just in proportion 
 as the United States gives chemical warfare its proper place 
 in its military establishment, just in that proportion will the 
 United States be ready to meet any or all comers in the future, 
 for the United States has incomparable resources in the shape 
 of the crude materials — power, salt, sulfur and the like — that 
 are necessary in the manufacture of gases. 
 
 If, then, there be developed industries for manufacturing 
 these gases in time of war, and if the training of the army 
 in chemical warfare be thorough and extensive, the United 
 States will have more than an equal chance with any other 
 nation or combination of nations in any future war. 
 
 It is just as sportsman-like to fight with chemical warfare 
 materials as it is to fight with machine guns. The enemy will 
 know more or less accurately our chemical warfare materials 
 and our methods, and we will have the same information 
 about the enemy. It is thus a matching of wits just as much 
 as in the days when the Knights of the Round Table fought 
 with swords or with spears on horseback. The American is 
 a pure sportsman and asks odds of no man. He does ask, 
 though, that he be given a square deal. He is unwilling to 
 agree not to use a powerful weapon of war when he knows 
 that an outlaw nation would use it against him if that outlaw 
 nation could achieve success by so doing. How much better 
 
THE FUTURE OF CHEMICAL WARFARE 439 
 
 it is to say to the world that we are going to use chemical 
 warfare to the greatest extent possible in any future struggle. 
 In announcing that we would repeat as always that we are 
 making these preparations only for defense, and who is there 
 who dares question our right to do so? 
 
INDEX 
 
 Absorbents, Requirements of, 237 
 
 Testing, 259 
 Absorptive activity, 237 
 Absorptive capacity, 238 
 Aeroplane, Smoke screen, 309 
 American Tissot mask, 224 
 Ammonia canister, 230 
 Ammonium chloride smoke, 327 
 Animals, Susceptibility to mustard 
 
 gas, 173 
 Anthracite coal, Activation of, 249 
 A. R. S. mask, 203 
 Arsenic derivatives, 180 
 Arsenic trichloride. Manufacture, 180 
 Arsenic trifliuoride, Manufacture, 180 
 Arsine, proposed use of, 180 
 Artillery, Gas, use of, by, 396 
 Aviation, Gas, use of, by, 380, 399 
 
 Baby Incendiary bomb, 340 
 
 Barrages, Gas, use of, in, 376 
 
 Benzyl bromide, 16, 141 
 
 Benzyl chloride, 16 
 
 Berger mixture, 290 
 
 Black signal smokes, 331 
 
 Black veiling respirator, 195 
 
 Blue cross. See Diphenylchloroarsine 
 
 Blue pencil, German, 346 
 
 Bombs, incendiary, 337 
 
 Box respirator, American, 209 
 
 English, 198 
 Break point of canisters, 262 
 Bromoacetone, 16, 138 
 
 German manufacture, 140 
 Bromobenzyl cyanide, 16, 142 
 Bromomethylethyl ketone, German 
 
 manufacture, 140 
 Bullets, incendiary, 344 
 
 Camouflage gases, 23, 416 
 Canister, life of. Gas concentration 
 and, 132 
 
 Temperature, effect of, 132 
 
 Testing, 260 
 Carbon dioxide, Manufacture, 129 
 Carbonite, 250 
 Carbon monoxide, 190 
 
 Canister, 191 
 
 Manufacture, 128 
 Cavalry, Gas, use of, by, 378 
 Cement, Soda lime, function in, 257 
 Charcoal, 239 
 
 Active, 242 
 
 German, 251 
 
 Inactive, 242 
 
 Manufacture, 242 
 
 Raw material, 239 
 
 Substitutes, 249 
 
 Tests of, 253 
 
 Theory of action, 241 
 Chemical Service Section, Organi- 
 zation, 34 
 Chemical Warfare, Future of, 435 
 
 Gases used in, 24 
 
 Historical, 1 
 
 Officers, duties of, 369 
 
 Strategy, relation to, 363 
 Chemical Warfare Service, Adminis- 
 trative division, 36 
 
 A. E. F., organization, 72 
 
 Development division, 61 
 
 Edgewood arsenal, 53 
 
 Gas defense division, 48 
 
 Liaison officers, 70 
 
 Medical division, 68 
 
 Organization, 35 
 
 Proving division, 63 
 
 441 
 
442 
 
 INDEX 
 
 Chemical Warfare Service, 
 Research division, 38 
 Training division, 65 
 Chemical Warfare troops, 92 
 Chenard bomb, 340 
 Chlorine, 116 
 
 Manufacture, 117 
 Properties, 123 
 Chloroacetone, 16 
 Chloroacetophenone, 16 
 Chloromethyl chloroformate, 21 
 Chloropicrin, 21 
 
 Manufacture, 145 
 Physiological test, 146 
 Properties, 146 
 Protection, 147 
 Tactical use, 148 
 Chlorovinyldichloroarsine, 188 
 ChlorosuKonic acid. Smoke material, 
 
 use as, 286 
 Cloud gas, 10, 116, 390 
 Coalite, 250 
 
 Cocoanut shell charcoal, 239 
 Cohune nut charcoal, 240 
 Complexene, 201 
 
 Horse masks, use in, 278 
 Cottrell Precipitation Tube, 299 
 
 Darts, incendiary, 343 
 Density of smoke clouds, 295 
 Development Division, C. W. S., 61 
 Dichloroethyl sulfide, 22, 80, 105 
 
 Detection, 166 
 
 Historical, 151 
 
 Manufacture, 152, 161 
 
 Mixtures, melting point of, 164 
 
 Properties, 163 
 
 Tactical use, 175, 417 
 
 Toxicity, 168 
 
 Vesicant action, 171 
 /3, /3'-Dichlorodivinylchloroarsine, 189 
 Dihydroxy ethyl sulfide, 160 
 Diphenylchloroarsine, 22, 182 
 
 Manufacture, 183 
 Diphenylcyanoarsine, 185 
 Diphosgene. See Trichloromethyl 
 chloroformate, 
 
 Dog mask, 280 
 Doughnut filter, 324 
 Dressier tunner kiln, 248 
 D-Shell, 134 
 Dugout blankets, 283 
 Dyes for signal smokes, 333 
 
 Edgewood arsenal, C. W. S., 53 
 Efficiency test. Absorbents, 259 
 
 Canisters, 262 
 Ethyldichloroarsine, 185 
 Ethylene, Manufacture of, 155, 158 
 Ethylene chlorhydrin, 158 
 Ethyl iodoacetate, 16, 141 
 Explosive dispersion, 314 
 
 ''Fkst gas attack," 10 
 
 First gas regiment, 93 
 
 Flammenwerfer, 349 
 
 Flaming gun, 347, 401 
 
 Food, protection of, against mustard 
 
 gas, 422 
 French artillery mask, 202 
 
 Gas, Defense against, 405 
 
 Effectiveness of, 375, 385 
 
 Humanity of, 13, 370, 387 
 
 Offensive use of, 385 
 
 Permanency of, 378 
 
 Requirements of, 116, 395 
 Gas alarms, 422 
 Gas cloud, height and spread, 394 
 
 Smoke in, 311, 403 
 Gas cylinder. Mobile, 17 
 Gas defense division, C. W."S., 48 
 Gases, Detection of, 415 
 
 Peace uses of, 427 
 
 Pharmacology, 353 
 Gas and Flame Regiment, 34 
 Gas mask. Development, 195 
 
 Physiological features, 232 
 
 Testing, 259 
 
 See also names of various masks 
 Gas shell, Markings, 28, 404 
 
 Value, 18, 396 
 
INDEX 
 
 443 
 
 Gassing chamber, 354 
 Gas training, 413 
 
 In France, 81 
 
 Value in peace, 373, 383 
 Gas warfare. Fundamentals, 388 
 
 Humanity, 13, 370, 387 
 German mask, 205 
 Greasene, 201 
 Green Cross shell, 148 
 Green-T Stoff, 142 
 
 Hand grenade, incendiary, 345 
 
 Hanlon field, 111 
 
 Hardness, Absorbents, test of, 259 
 
 Hague conference. Poison gases, 
 action on, 6 
 
 Homomartonite, 16, 138 
 
 HopcaUte, Carbon monoxide absor- 
 bent, 193 
 
 Horse boots, 280 
 
 Horse mask, 277 
 
 Humanity, Gas warfare, 13, 370, 387 
 
 Hypo helmet, 196 
 
 Incendiary materials, 336 
 
 Tactical use of, 402 
 Infantry, Gas, use of, by, 377, 400 
 Intelligence section, 113 
 Inter-allied gas conference, 79 
 Irritants, Efficiency of, 389 
 
 Testmg, 359 
 Ivory nut charcoal, 241 
 
 Kieselguhr, Soda lime, function in, 
 
 257 
 Kupramite, 230 
 
 Lachrymators, 15, 137 
 
 Comparative value, 143 
 Protection, 143 
 Testing, 356 
 Lachrymatory shell. Tactical value, 
 
 15 
 Lamp black," Charcoal from, 250 
 Lantern test. Mustard gas, 166 
 Leak detecting apparatus, 266 
 Leakage, Canister, testing of, 261 
 
 Levinstein reactor, 158 
 
 Lewisite, 23, 187 
 
 Liaison officers, 70 
 
 Lime, Soda lime, function in, 257 
 
 Livens' projector, 18, 391 
 
 Livens ' smoke drum, 304 
 
 M-2 Mask, 201 
 Man test, 262 
 Martonite, 16, 138 
 Mask, Development, 405 
 
 Disinfection, 269 
 
 Field tests, 270 
 
 Issuance, 423 
 
 See also Gas mask 
 
 See also Names of masks 
 Mechanical dispersion, 313 
 Medical division, C. W. S., 68 
 Medical section, A. E. F., 114 
 Methyldichloroarsine, 181 
 Moisture, Absorbents, tests of, 259 
 Mustard gas. See Dichloroethyl sul- 
 fide. 
 
 Navy, Canister, 230 
 
 Gas, use of, by, 381 
 
 Smoke funnel, 305 
 Nelson cell, 117 
 
 "Nineteen nmeteen" canister, 325 
 "Nineteen nineteen" Model Ameri- 
 can Mask, 225 
 
 Odors, Testing of, 358 
 Oleum, Smoke material. 
 Overall suit, 273 
 
 as, 286 
 
 PaUte. See Chloromethyl chlorofor- 
 
 mate 
 Penetration apparatus. Toxic smoke, 
 
 measurement of, 315 
 P-Hehnet, 197 
 PH-Heknet, 197 
 Phosgene, 14, 126 
 
 Manufacture, 127 
 
 Properties, 130 
 
 Protection, 131 
 
 SheU filling, 132 
 
 Tactical use, 134 
 
444 
 
 INDEX 
 
 Phosphorus, Smoke material, 286, 382 
 
 Stokes' mortar, use in, 393 
 
 See also Smoke 
 Physiological action, Phosgene, 135 
 
 Mustard gas, 168 
 
 Toxic Smokes, 316 
 Pressure drop apparatus, 266 
 Protective clothing, 272 
 Protective gloves, 274 
 Protective ointments, 275 
 Proving division, C. W. S., 63 
 Pumice stone. Phosgene shell, use 
 in, 130, 135 
 
 Research division, C. W. S., 38 
 Resistance, Canister, test of, 261 
 
 Decreased, 410 
 Respirator, See Gas mask, Mask 
 
 Sag paste, 277 
 Screening smokes, 285 
 
 See also Smoke 
 Screening power, Smoke cloud, 285 
 Selenious acid. Mustard gas 
 
 detector, 166 
 Shell, Gas, Filling of, 132 
 
 Value, 18, 396 
 
 Incendiary, 344 
 
 Markings, 28, 404 
 
 Pumice stone and phosgene in, 
 130, 135 
 
 Smoke, 303 
 Ships, Screening Smoke, 299, 305 
 Shrapnel, Gas in connection with, 379 
 Signal smokes, ,330 
 
 Tactics, 333 
 Silicon tetrachloride, Smoke material, 
 
 use as, 290 
 Smoke, Intensity, measurement of, 
 296 
 
 Tactical value, 310, 402 
 
 Use in offense, 401 
 
 See also, Screening, Signal and 
 Toxic Smokes 
 Smoke box, 299 
 Smoke candle, 301, 372 
 
 Toxic, 318 
 
 Smoke cloud. Properties, 116, 285, 
 
 395 
 Smoke drum, 304 
 Smoke filters, 322 
 
 Felt, 324 
 
 Paper, 323 
 
 Testing, 327 
 
 Theory, 326 
 Smoke funnel, 305 
 Smoke grenade, 302 
 Smoke knapsack, 306 
 Smoke particles. Measurement of, 292 
 
 Size of, 291 
 Smoke screen. Purpose of, 309 
 Smoke shell, 303, 307 
 Smoke signals, 333 
 Sneezing gas. See Diphenylchloro- 
 
 arsine 
 Soda lime. Composition, 256 
 
 Requirements, 255 
 Sodium hydroxide. Soda lime, func- 
 tion in, 257 
 Sodium permanganate. Soda lime, 
 
 function in, 257 
 "SoHdoil", 336 
 Spray nozzles, 357 
 Staff troops, C. W. S., 92 
 Standard Box respirator, 198 
 Stokes' mortar, 20, 392 
 Sulfur chloride. Manufacture, 157 
 Sulfuric acid smoke, 328 
 Sulfur trioxide. Smoke material, use 
 
 as, 289 
 SuperpaUte. See Trichloromethyl 
 chloroformate 
 
 Tactical use, Chloropicrin, 148 
 
 Dichloroethyl sulfide, 175, 417 
 
 Gases in offense, 385 
 
 Incendiary materials, 402 
 
 Lachrymatory shell, 15 
 
 Phosgene, 134 
 
 Screening smokes, 310, 402 
 
 Signal smokes, 333 ' 
 Tactics, Chemical Warfare and, 363 
 Tanks, Smoke screen for, 309 
 Thermal dispersion, 313 
 
INDEX 
 
 445 
 
 Thermit, Uses, 393 
 
 Tin tetrachloride, Smoke material, 
 
 use as, 289 
 Tissot mask, 202 
 Titanium tetrachloride, Smoke 
 
 material, use as, 290 
 Tobacco smoke, 328 
 Total obscuring power of smoke, 295 
 Touch method. Irritants, testing of, 
 
 362 
 Toxicity, Gases, testing of, for, 353 
 Toxic smoke, 313 
 
 Candle, B. M., 319 
 
 Candle, Dispersoid, 320 
 
 Penetration, 314 
 
 Quantitative relationship, 316 
 Training division, C. W. S., 65 
 Trench mortar, 20, 392 
 Trichloromethyl chloroformate, 20 
 Trichloronitromethane. See Chlo- 
 
 ropicrin 
 /3, /3', /3"-TrichIorotrivinyIarsine, 189 
 
 T-StofT, 141 
 Tyndall meter, 299 
 
 Ultramicroscope, Smoke particles, 
 measurements of, 292 
 
 Vapor tests. Irritants, testing of, 359 
 
 Versatility of absorbents, 238 
 
 Vincennite, 15, 180 
 
 Vision chart, 271 
 
 ' ' Vomiting gas. ' ' See Chloropicrin 
 
 War gas. See Gases 
 War, humanity of, 6 
 Wave attack. Disadvantages, 16 
 
 Xylyl bromide, 16, 141 
 
 Yellow cross. See Dichloroethyl sul- 
 fide 
 Yellow smoke, 331 
 Yperite. See Dichloroethyl sulfide 
 
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