BATTLING WITH LIQUID FIRE
Somewhat associated with gas warfare was another form of offensive which was introduced with the purpose of breaking up the dead-lock of trench warfare. A man could protect himself against gas by using a suitable mask and clothing, but what could he do against fire? It looked as if trench defenders would have to give up if attacked with fire, and so, early in the war, the Germans devised apparatus for shooting forth streams of liquid fire, and the Allies were not slow to copy the idea.
The apparatus was either fixed or portable, but it was not often that the fixed apparatus could be used to advantage, because at best the range of the flame-thrower was limited and in few places were the trenches near enough for flaming oil to be thrown across the intervening gap. For this reason portable apparatus was chiefly used, with which a man could send out a stream for from a hundred to a hundred and fifty feet. On his back he carried the oil-tank, in the upper part of which there was a charge of compressed air. A pipe led from the tank to a nozzle which the man held in his hand, using it to direct the spray.
There was some danger to the operator in handling a highly inflammable oil. The blaze might flare back and burn him, particularly when he was lighting the stream, and so a special way of setting fire to the spray had to be devised. Of course, the value of the apparatus lay in its power to shoot the stream as far as possible. The compressed air would send the stream to a good distance, but after lighting, the oil might be consumed before it reached the desired range. Some way had to be found of igniting the oil stream far from the nozzle or as near the limit of its range as possible. And so two nozzles were used, one with a small opening so that it would send out a fine jet of long range, while the main stream of oil issued from the second nozzle. The first nozzle was movable with respect to the second and the two streams could be regulated to come together at any desired distance from the operator within the range of the apparatus. The fine stream was ignited and carried the flame out to the main stream, setting fire to it near the limit of its range. In this way a flare-back was avoided and the oil blazed where the flame was needed. The same sort of double nozzle was used on the stationary apparatus and because weight was not a consideration, heavier apparatus was used which shot the stream to a greater distance.
But flame-throwing apparatus had its drawbacks: there was always the danger that the tank of highly inflammable oil might be burst open by a shell or hand-grenade and its contents set on fire. The fixed apparatus was buried under bags of sand, but the man who carried flame-throwing apparatus on his back had to take his chances, not knowing at what instant the oil he carried might be set ablaze, turning him into a living, writhing, human torch. Because of this hazard, liquid fire did not play a very important part in trench warfare; to set fire to the spray at its source with a well directed hand-grenade was too easy.