Gas and flame in modern warfare

by Samuel James Manson Auld

Though it was not realised at the time, it is almost certain that the Germans started to use gas in shell almost simultaneously, and probably actually in the first attack, with the use of the poisonous gas clouds in the attacks of April and May, 1915. Many instances came to notice of men’s eyes being strongly affected to such an extent that they could not keep them open. There seemed to be something in the air which made an unprotected man weep copiously if he tried to keep his eyes open, and of course if he closed them he could not see what he was doing.

These effects, and a peculiar smell which was noticed both during and after the gas-cloud attacks, gave rise to the belief that something like formaldehyde was being used by the Germans mixed with some chlorine gas. Others described the smell as being that of chloroform or ether, but nobody could say definitely what the material actually was. It was only after a number of blind shell had been obtained and examined that it was realised that the Germans were firing shell filled with liquid which had a powerful lachrymatory effect.

It does not appear certain whether the use of lachrymatory liquids for putting men out of action by making their eyes water is in itself contrary to The Hague Convention, as the vapours need not actually be poisonous. This was the case with the first German gas shell, as it was found that the liquid contained consisted only of a material known chemically as “xylyl bromide.” The vapour of this liquid and of many similar substances has a most powerful effect on the eyes, like that of onions but much stronger. Except in very high concentrations it cannot be regarded as poisonous—at any rate not in the sense that chlorine is poisonous.

Examination of the German lachrymatory shells showed that the liquid was contained inside the shell in a sealed lead vessel so that the material should not come in contact with the steel of the shell, which it destroys gradually. Shell of this kind, though termed gas shell, are not really such, as the liquid has to be broken up into fine droplets by the explosive charge of the shell before the vapour can produce its effect. The liquid has no pressure of its own inside the shell and depends entirely on the bursting charge to get it distributed into the atmosphere.

The xylyl bromide used by the Germans was not pure, but contained a big proportion of benzyl bromide, showing that it had been made by the action of bromide on coal-tar light oil from which most of the toluene had been removed for the manufacture of the well-known high explosive, trinitrotoluene.

The effect of xylyl bromide on an unprotected man is instantaneous and remarkable. Even such small proportions as one volume of vapour diluted with one million volumes of air will at once make a man weep so copiously that he cannot possible keep his eyes open.

Obviously a material of this kind has great military value, for though it does not put men out of action permanently by killing them it neutralises their effectiveness to such an extent that for the time being they may be regarded as of no military importance. In strong concentrations the effect on the eyes is most powerful. I have walked into an area which was being bombarded with lachrymatory shells and suddenly got the effect just as if I had been hit in the face. Fortunately the lachrymation has no lasting effect on the eyes, and a man on getting into pure air very quickly recovers.

Throughout the spring and summer of 1915 these lachrymatory shells were used in considerable numbers, especially in the vicinity of Ypres, and at times the ramparts of that much bombarded town reeked of lachrymatory vapour and nobody could stay in certain spots for any length of time without having his eyes protected by specially constructed goggles or by wearing a gas helmet right over his head.

Taking it altogether we were not troubled nearly so much by this new type of gas as were the French, in the southern part of the line. In much the same way that the gas cloud was developed by the Germans against the English the gas shell were developed chiefly against the French, and very much larger numbers were employed against the French positions than we had to contend with during the first six months or so. Later on things were more equallised in this direction. Captured German documents and statements by prisoners showed us that the Germans were counting very considerably on the effect produced by the lachrymatory shell, and detailed instructions for their use in various circumstances were carefully laid down. The lachrymatory shell was known by the Germans as “T-Shell,” and the xylyl bromide as “T-Stoff,” and instructions were laid down for the use of this material. Another kind of shell was known as “K-Shell,” which up to that time had not been used against us, or at any rate had not been recognised.

The T-Shell was particularly to be used against positions which it was not intended to occupy immediately, the reason for this being that T-Stoff hangs about for a long time. Some of the liquid is apt to be spread about the ground and gives off enough vapour to make the neighbourhood of the shell hole uninhabitable for many hours, and in favourable condition—for the enemy—for several days. The K-Shell, on the other hand, was intended to be used against infantry positions and strong-points which it was hoped to assault and capture within an hour or two of the bombardment or on areas which it was hoped to traverse during a big attack.