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 materials 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 technical and most highly specialized Service under the War Department. There is no class of people in civil life, and no officers or men in the War Department, who can take up chemical 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 common 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 Service 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 realize its effectiveness we need only remember that more than 27 out of every 100 casualties on the field of battle were from gas alone. Unquestionably many of those who died on the battlefield from other causes suffered also from gas. No other single element of 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 completely 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 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 in the Argonne would have been doubled. In fact, the advance might even have been entirely stopped, thus prolonging the war into the year 1919.
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 why chemical warfare was first widely advertised throughout the world as inhumane and horrible. 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 paraphernalia that was later employed to 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 war propaganda to impress upon everybody the fact that the German was capable of using any means that he could develop in order to win a victory. He had no respect for previous agreements or ideas concerning warfare. This propaganda kept up the morale and fighting spirit of the Allies, and was thoroughly justifiable upon that score, even when it led to wild exaggeration.
The chlorine used in the first attack by the German is the 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 particular method of warfare under consideration.
=American Gas Casualties.= The official list of casualties in battle as compiled by the Surgeon General’s office covering all cases reported up to September 1, 1919, is 258,338. Of these 70,752, or 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 while 24.85 per cent of all casualties from bullets and high explosives 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 fundamentals of chemical warfare, in so far as they pertain to poisonous 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, supply, 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 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 principal 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 500 to 1,000 pounds of other gases when forcing the wearing of the mask alone is desired. The great economy resulting from their use is thus apparent. 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.
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 gas on the other hand forces the immediate wearing of the mask.
MATERIAL 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’ projector 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 1½ or 1¾ 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, specifications 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 putting off cloud attacks. The toxic smoke candle is perfectly safe under all conditions and can be made in any size desired. 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. Experience 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 synchronized, 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 available, 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 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-Inch 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 increasing 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, all 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 exploding exerts the full force of high explosive upon the surroundings, whether bombs, pill boxes, barbed wire or trenches, to say nothing of personnel.
=High Explosive in Projectors.= When these are burst by the hundreds on a small area everything movable is blotted out. Thus concrete machine gun emplacements, lookout stations, 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 German 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’ projector 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 phosphorus or has witnessed the ease with which it burns when exposed to air, wet or dry, has a most wholesome 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 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 considerable 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 when 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 upwards 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 during 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 experimentally, 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 dead vegetation. This vegetation was killed and bleached so that it readily showed up in aeroplane photographs. The visibility of a gas cloud 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 concentrations, 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 mentioned 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 substances being used by the Infantry, it is understood that an ample number of Chemical Warfare officers will be present 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 essential 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 OF GAS
The Artillery of the future will probably fire more gas than any other one branch of the Army. There 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 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 organized 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 groups 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 persistent gases will not be chosen unless they will persist under ordinary conditions for two or three days or more. Accordingly, 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 when 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 considerable wind, it must be shortened. Another important consideration 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 considerations 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 concentration 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, considered as a group because they are used for harassing purposes, 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 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, however, 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 Germans 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 evidently 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 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 encampments 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 handling, whereas artillery shell must be strong enough to withstand 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 overloaded. 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, illustrates 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 everything else in his possession. The same thing will be true of any gas equipment if it proves its worth.
SMOKE AND INCENDIARY MATERIALS
So far nothing has been said in regard to smoke or incendiary 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 poisonous, are not a danger to our own troops, although they may hamper movements and add to the difficulty of taking a position, 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 frequently, 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 thrower. 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.
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 appreciable 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 impenetrable 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 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 knapsack. 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 OF GAS CLOUD
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 skillfully. 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 searchlights, by star bombs or other means for illuminating the battlefield. 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 grayish 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 Warfare 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.
##