auld: methods of gas warfare 53 



Front, and are still in course of development. The enemy 

 started using them soon after the first cloud attack. He began 

 with the celebrated "tear" shells. A concentration of one part 

 in a million of some of these lachrymators makes the eyes water 

 severely. The original tear shells contained almost pure xylyl 

 bromide or benzjd bromide, made by brominating the higher 

 fractions of coal-tar distillates. 



The German did his bromination rather badly. As you know, 

 it should be done very carefully or much dibromide is produced, 

 which is solid and inactive. Some of the shells contained as 

 much as 20 per cent dibromide, enough to make the liquid pasty 

 and inactive. The shells used contain a lead lining, and have a 

 partition across the shoulder, above which comes the T. N. T. 

 and the fuse. These shells had little effect on the British, but 

 one attack on the French, accompanied by a very heavy bom- 

 bardment with tear shells, put them out badly. The eyes of 

 the men were affected, and many of the men were even anesthe- 

 tized by the gas, and were taken prisoner. 



Our first big experience was an attack at Vermelles. The 

 Germans put down a heavy barrage of these shells and made 

 an infantry attack. The concentration was great, the gas 

 went through the helmets, and the men even vomited inside 

 their helmets. But it is difficult to put down a gas barrage, and 

 there is danger that it will not be a technical success. In the 

 instance cited certain roads were not cut off sufficiently, so that 

 reinforcements got up. This attack, however, opened our eyes 

 to the fact that, as in the case of gas clouds, concentration 

 would be developed so as to make it high enough to produce 

 the required effect under any circumstances. 



\Mien the Germans started using highly poisonous shells, 

 which was at the Somme in 1916, they did not attend to this 

 sufficiently, although enormous numbers of shell were used. 

 The substance used was trichloromethyl-chloroformate, but not 

 in great strength. It had no decided reaction on the eyes, 

 hence the men were often caught. 



The quantity of gas that can be sent over in shells is small. 

 The average weight in a shell is not more than six pounds, where- 

 as the German gas cylinders contain 40 pounds of gas. To put 



