Page:Popular Science Monthly Volume 91.djvu/36

 The European Trenches Are Not the Only

��Gas masks a new development? Hardly. They have been used for years in American industries. At the left a girl is shown putting caps on bottles of disinfectants

���Foreign cotton has to be disinfected to kill the boll weevil. Here it is treated with hydrocyanic gas, pumped at a pressure of 1,000 pounds a square inch. A whiff of the gas is fatal

��Handling barrels of chloride of lime which gives off an irritating dust pow- der and chlorine gas, the destructive gas used in trench warfare. The men are well protected by their masks

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