46 auld: methods of gas warfare 



Then came the first gas attack, and the whole course of the 

 war changed. That first attack, of course, was made against 

 men who were entirely unprepared — absolutely unprotected. 

 You have read quite as much about the actual attack and the 

 battle as 1 could tell you, but the accounts are still remarkably 

 meager. The fellows who could have told most about it didn't 

 come back. The Germans have claimed that we had 6000 

 killed and as many taken prisoners. They left a battle field 

 such as had never been seen before in warfare, ancient or modern, 

 and one that has had no compeer in the whole war except on the 

 Russian front. 



What the Germans expected to accomplish by it I am not 

 sure. Presumably they intended to win the war, and they might 

 conceivably have won it then and there if they had foreseen the 

 tremendous effect of the attack. It is certain that they expected 

 no immediate retaliation, as they had provided no protection 

 for their own men. They made a clear and unobstructed gap 

 in the lines, which was only closed by the Canadians, who rallied 

 on the left and advanced, in part through the gas cloud itself. 



The method first used by the Germans, and retained ever 

 since, is fairly simple, but requires great preparation l^eforehand. 

 A hole is dug in the bottom of the trench close underneath the 

 parapet, and a gas cylinder is buried in the hole. It is an ordi- 

 nary cyhnder, like that used for oxygen or hydrogen. It is then 

 covered first with a ciuilt of moss, containing potassium car- 

 bonate solution, and then with sand bags. When the attack is 

 to be made the sand bags and protecting cover are taken off 

 the cylinder, and each cylinder is connected with a lead pipe 

 which is bent over the top of the parapet. A sand bag is laid 

 on the nozzle to prevent the back "kick" of the outrushing 

 gas from throwing the pipe back into the trench. Our own 

 methods are practically identical with those first used by the 

 Germans. 



The success of a cloud gas attack depends on thorough prep- 

 aration beforehand. The attackers must know the country, 

 the layout of the trenches, and the direction and velocity of 

 the wind with certainty. Favorable conditions are limited 

 jjractically to wind velocities between 12 and 4 miles an hour. 



