Gas and flame in modern warfare

by Samuel James Manson Auld

The “surprise effect,” which was mentioned above as being the third fresh feature of this new-era gas-cloud attack, took the form of making the attack in the dark and at a time when men were least prepared—that is, just before the morning “Stand to,” the hour before dawn, when all troops in the trenches stand to arms. By making the attack at night, or at any rate in the dark, the boche achieved two objects: First of all, there were better wind conditions for an attack, because the night winds tend to flow down toward the earth and keep the gas cloud low-lying and thick, whereas in the day the sun warms the ground and produces so many upward currents of air that the cloud gets lifted up and dissipated; in the second place it was impossible to see the cloud when it was first liberated, and this reduced the means of detecting the attack to only two—the hissing noise of the gas escaping from the cylinders and the smell of the advanced parts of the cloud.

Later on it was known that the best hours for all gas attacks, both cloud and shell bombardment, are in the night; and as a matter of fact practically all gas warfare is now carried out at night, but at that time the significance of this was not grasped, and many of our casualties were due to lack of preparedness, numbers of men being caught “on the hop” and overwhelmed.

Some most important steps in improving our protecting measures were taken as a result of the lessons learned from the attack; in fact, it may be taken that all measures in defence against gas have been learned from bitter experience, and to this extent the sufferings of the victims may be taken as having at any rate some compensating value. In such a new and strange and continually developing kind of warfare very little can be done by a priori argument. This fact we have always tried to impress on the men—that the gas warfare orders, sometimes apparently trivial and frequently wearisome and annoying, have all been made as the result of lessons learned from actual attacks.

Among the chief things that were done after the December nineteenth attack was the improvement of our system of alarms.

The bells and horns in the front line had been found quite insufficient, especially for warning people in the rear; and the telephone could not be depended on for this purpose owing to the possibilities of the wires being cut by shell fire. To protect them from being cut, all wires would have to be buried at least six feet deep in the ground, and this is practically impossible owing to the work involved.

It would consequently be fatal to depend on telephonic communication, especially as a gas attack is nearly always accompanied by a pretty heavy bombardment of rear lines. In one case I knew, during just such a bombardment, the staff captain at a brigade headquarters was talking to one of the battalions when the whole telephone instrument seemed to burst into a sheet of flame in his hands, owing to a cut wire. The battalion concerned was isolated for more than an hour as a result, and anything might have happened in the meantime.

For these reasons it was decided to adopt for gas alarms sirens worked by compressed air, which would make a noise sufficiently loud and distinctive to be heard long distances away. The type of siren which was used has been kept in use ever since in continually increasing numbers and has proved extraordinarily useful. It is known as the Strombos horn, and consists of the horn proper and two iron cylinders of compressed air charged to a pressure of one hundred and fifty atmospheres. Only one cylinder at a time is connected to the horn, the other being kept as a reserve.

The Strombos horns are mounted in the trenches in such a way as to protect them from shell splinters as far as possible. This is generally done by packing them round carefully with sandbags, only the mouth of the horn being displayed and pointing toward the rear. Every sentry must know how and when to sound the horn. All he has to do when he realises that a gas attack is being made, or on receiving instructions from an officer to do so, is to loosen the tap on the cylinder one complete turn, when the horn will sound continuously for more than a minute. The noise is terrific and in an enclosed space or in a quiet region it is absolutely deafening. In the trenches, however, it is none too loud, and the distances between the horns in the front system of trenches are never more than four or five hundred yards. Farther back in the chain, toward the rear, the distances can be increased. Horns are now installed at battalion, brigade and divisional headquarters. By turning them on when the noise of those in front is heard it is possible to pass the alarm in an incredibly short space of time and thus forestall the cloud of gas to such an extent that every man in the support trenches or in rest billets or the villages behind the firing line is aware that an attack is in progress and gets ready to protect himself.

Naturally, things don’t always work out exactly according to schedule. The horns are frequently damaged. In one place I was at, just this side of the canal, near Boesinghe, a heavy German trench mortar wrecked three of our Strombos horns within a week, and another and less suitable position had to be found for the alarm. Then there are occasional false alarms. These sometimes arise from individual men “getting the wind up” from a bombardment by gas shell and thinking that a cloud attack is being made. Others I am afraid have been more in the nature of experiments “to see how it works.” After all, it must be a great temptation to a sentry to be in charge of a Strombos horn and never have the pleasure of turning it on.

False alarms are a great nuisance, however, and good arrangements have now been made to prevent their spreading. It is possible to avoid all the unnecessary disturbance to which troops are subjected by a false gas alarm. This disturbance is particularly objectionable in back areas where regiments returned from the trenches are in billets. When the alarm goes everybody has to turn out—probably in the middle of the night. Sentries wake the officers and men in all the billets; messengers have to be sent post-haste to outlying villages or farms with which there is no telephonic communications; respirators are hurriedly inspected and placed in the alert position; the gas-proof curtains of cellars and dugouts are adjusted; the officers move about in the darkness to see that all their men are accounted for and ready; every one is in a state of expectancy—and then the word comes through that it is a false alarm, and the men go back, cursing, to their billets. Not only is an occurrence of this kind wearying to tired troops, but it has the old disadvantage of crying “Wolf, wolf!” when there is no wolf—the consequent determination on the part of the men not to take the next alarm so seriously.