It must be remembered that there are certain things that gas shell cannot do. They cannot replace high-explosive shell for the demolition of fortified works, for example. Nor can they be used for cutting barbed wire previous to an advance; and the creeping barrage that preceded the assaulting infantry cannot be made up by gas shell. An S O S barrage in No Man’s Land, to cut up an attack, also would have to be shrapnel and H. E. so as not to gas the defending troops. When all these are cut out it will be realised that the proportion of gas shell that are used against living targets must be very big indeed. It is hardly too much to assert that at the present day, of the actual methods of attacking men direct gas is the most important. It must be realised also that it can become, and is likely to become, still more important, and that the fight between the offence and the defence on both sides will continue until the end of the war. Since December of last year the boche has been copying a method invented by the British for firing a large number of big drums of gas simultaneously. These drums are used chiefly against the front-line troops and are generally filled with pure phosgene. As each bomb contains a gallon and a half of liquid and many hundreds are fired at the same moment a good high concentration of gas is produced. Warning is given by the tremendous roar from behind the German lines when the flock of canister or rum-jar bombs starts on its way. Every man who hears the noise gets his mask on at once, even before there is any sign of gas; and if he does this there is little danger, as the respirators are quite capable of dealing with even the very high concentrations of phosgene produced. If a man keeps his head and obeys orders there is little to fear from gas. But discipline must be high. As one Tommy said: “You must be so well disciplined that when the gas alarm goes you will even drop the rum ration so as to get your respirator on in time.” Beyond that it is simply a question of carrying on the work in hand while wearing a respirator, and this is entirely a matter of practice. CHAPTER X Liquid Fire--First used by Germans in July, 1915--A great surprise and success--German hopes from it--Construction of a flame projector--Flammenwerfer companies--Their perilous duties and incidents of desertion from them--Improved types of projectors--Co-operation of machine-gun fire--Failure of liquid fire--Its short duration and short range--Ease of escape from it. When the German Army entered on its policy of frightfulness there was none of its new and unprincipled methods which had more immediate and striking success than the use of liquid fire. And there is now none of all its methods of frightfulness which has fallen more into disrepute, and which has had less success when once the first surprise was over.