METHODS OF GAS WARFARE 71 



high explosives or to gas clouds. Take, for instance, a 

 field howitzer, dug into a pit with a certain amount of 

 overhead cover for the men, who come in from behind 

 the gun. The men are safe from splinters, and only a 

 direct hit will put the gun out of action. But the gas will 

 go in where the shell would not. It is certain to gas some 

 of the men inside the emplacement. The crew of the gun 

 must go on firing with gas masks on, and with depleted 

 numbers. Thus it nearly puts the gun out of commission, 

 reducing the number of shots say from two rounds a 

 minute to a round in two minutes, and may even silence it 

 entirely. Another example is a position on a hillside with 

 dugouts at the back, just over the crest, or with a sunken 

 road behind the slope. Almost absolute protection is af- 

 forded by the dugouts. The French tried three times to 

 take such a position after preparation with high explos- 

 ives, and each assault failed. Then they tried gas shells, 

 and succeeded. The gas flows rapidly into such a dug- 

 out, especially if it has two or more doors. 



Among the effective materials used by the Germans for 

 gas shells were mono- and tri-chloromethyl-chloroformate. 

 Prussic acid never appeared; the Germans rate it lower 

 than phosgene in toxicity, and the reports concerning it 

 were obviously meant merely to produce fear and distract 

 the provisions for protection. 



During the last five months the actual materials and 

 the tactics used by the Germans have undergone a com- 

 plete change. The lachrymator shells are less depended 

 upon than formerly for "neutralization," but are still a 

 source of annoyance. Mere annoyance, however, may be 

 an effective method of neutralizing infantry. For m- 

 stance, where large amounts of supplies and ammunition 

 are being brought up there are always cross-roads where 

 there is confusion and interference of traffic^ A few gas 

 shells placed there make every man put on his mask, and 

 if it is a dark night and the roads are muddy the resulting 

 confusion can be only faintly imagined. It may thus be 



