Gas and flame in modern warfare

by Samuel James Manson Auld

Throughout 1915 England was pouring new divisions of its National army into France. As with all new troops the procedure adopted at the time was to bring these divisions by easy stages to within a short distance of the front line, and then send them in by companies for a four day “instructional tour” in the trenches to pick up all the wrinkles and habits from the seasoned troops holding the line. After the whole formation had been put through it in this way the division would be allotted a definite part of the line, taking it over possibly from the troops with whom it had been in for instruction and allowing the latter to get out for a much needed rest, or to get “fattened up” for some impending or progressing show elsewhere.

One such new division, absolutely fresh from England and with no war experience whatever, was the target selected by the boche for his new deviltry. The portion of line allotted to this division was on the outermost part of the Ypres salient and included the ruins of the little village of Hooge right at the point of the salient. This position had always been a hot corner—“unhealthy” in the British army parlance—and had changed hands several times. The trenches there were poor as it was almost impossible to get effective work done on them owing to their exposed position. Indeed there were many parts of the line where no movement was possible by day and the men on the posts had to lie “doggo” until night. The two lines were very close together—in many places less than twenty yards—and it was quite possible to hurl hand grenades from one set of trenches to the other. It was on this position of the line, over a front held by two battalions, that the attack was made.

After a bombardment of several days, a mine was exploded under the front line and then immediately afterward, at 3:20 A. M. on the morning of the 29th of July and without the slightest warning, the front line troops were enveloped in flames. Where the flames came from could not be seen. All that the men knew was that they seemed surrounded 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 a saphead. Shouts and yells rent the air as individual 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. Then the flames stopped and machine guns began to take toll of the fugitives. Only one man from the front trenches is known to have returned. German infantry following up, poured into the breach in the line, widened it, took our positions as far back as Sanctuary Wood, and then consolidated.

Ten days afterward we counter attacked and won back the whole of the line concerned but at very considerable cost. Incidentally, we captured two of the German flame projectors, one of them complete, and they proved to be of the greatest possible use to us subsequently for educating the army in the new warfare, and for inspection by our own experts with a view to their duplication for retaliation.

Any one attempting to blame the troops attacked for their retirement can hardly appreciate the circumstances, and, I am convinced, over-estimates his own capacity for resistance. This attack was an utter surprise—the kind of warfare was unknown and unheard of. Imagine being faced by a spread of flame exactly similar to that used for the oil burners under the biggest boilers, but with a jet nearly sixty feet in length and capable of being sprayed round as one might spray water with a fire hose. Personally, I am pretty sure, had I been there, that I should have hopped it if I had not been fried by the heat or frozen with terror. Later, when we knew the limitations of these things it was different, though even then it is a pretty good test of a man’s nerve.

The flame projectors taken by the 14th Division in the counter attack were simple but very interesting in construction. The main part was a cylindrical vessel of steel about two feet in height and fifteen inches in diameter provided with straps so that it could be carried on a man’s back. At one side about two-thirds of the way up was a filling hole for oil, closed by a screw cap. Near the top was a pressure gauge attachment and toward the base was a lock closed by a lever handle and to which could be attached a long length of flexible hose ending in a peculiar shaped nozzle.

On examination it was found that the body of the projector was divided internally into two compartments which could be connected by opening another tap. The upper compartment was the compressor and the lower the oil reservoir. The compressor chamber was filled to a pressure of twenty-three atmospheres with deoxygenated air or nitrogen. Air itself cannot be used because of its oxygen content forming an explosive mixture with the vapours from the oil, and any heating on compression, or back-flash from the flame or fuse, might make things very unpleasant for the operator. The nitrogen required for the flame projectors is carried into the field in large cylinders about 4 feet 6 inches in length and 6 inches in diameter. Several of these cylinders have been captured from the enemy since. These cylinders are actually taken into the trenches and the flame projectors charged from them there.

The combustible liquid used in the flame throwers has varied in source and composition from time to time, but it invariably has one characteristic which appears to be essential for good results—it must have light or easily volatile and heavy and less volatile fractions mixed in carefully graded proportions. The heavy oil has sometimes been a petroleum product and sometimes a tarry residual oil from the distillation of wood. The light portion, which insures the jet’s keeping alight was originally a light gasolene, but at one period, whether from shortage of petrol or not I do not know, the place of the latter in the mixture was taken by ordinary commercial ether.

The lighting device, fixed at the end of the flexible hose, is the most ingenious part of the whole contrivance and is so made that the oil ignites spontaneously the minute the jet is turned on, and is kept alight by a fiercely burning mixture which lasts throughout the discharge.

The nozzle is about 9 inches long and detachable so that replacement is easy. It clips into the end of the tube and is held in position by an annular ring. When the oil with its twenty-three atmospheres pressure behind it is rushed out of the jet, it forces up the plunger of a friction lighter and ignites a core of a fierce burning fuse mixture which fills the whole of the space between the central tube and an outer casing. The latter consists of a thick wick soaked in paraffin wax and fitting loosely into a thin brass case.