THE CHEMICAL WARFARE SERVICE 171 



funnel and the smoke box are intended primarily for merchant 

 vessels and the oleum smoke for fighting vessels. The oleum 

 smoke is also very effective for concealing tanks, the oleum 

 being sprayed into the exhaust. 



For land work the Bureau of Mines smoke candle is more 

 satisfactory than the smoke funnel or smoke box because the 

 smoke can be generated simultaneously at a greater number 

 of points along the front. It is ignited by means of an ordinary 

 match and emits a white dense smoke of large volume for four 

 minutes. A smoke knapsack was also devised consisting of 

 two cylinders which can be carried on a man's back. The 

 apparatus will give a dense cloud of smoke continuously for 

 15 minutes and the operator can regulate the production of the 

 cloud instantly by adjusting the valves on the discharge pipe. 

 Two men can cover the front of a company. 



A Livens smoke projectile consists of a half -capacity 8-inch 

 Livens drum adapted for combustion smoke by drilling holes 

 around the top and filling these with fusible metal. The charge 

 consists of the standard Bureau of Mines smoke mixture. 

 Each shell will produce a smoke cloud of very large volume for 

 five minutes. 



OTHER PYROTECHNICS 



Various other pyrotechnic devices were studied, developed 

 or improved, mention of which may be made, but details of 

 which must be lacking. 



Gas shells were developed with special lead, glass or enamel 

 lining, for use with the lachrymators in particular, but also 

 with other gases. It was necessary to use special precautions 

 with American filled shell, since they had to stand from three 

 to six months before being used. 



Hand grenades were developed and improved, all types 

 (H. E., gas, smoke and incendiary) being studied. Special 

 training grenades were developed, which later offered promise 

 of field use. 



Flaming liquid guns were developed but owing to the gener- 



