6o4 proceedings: Washington academy oe sciences 



culties with manufacturing processes, so that the quality also had been 

 brought up to a high standard. The lecturer showed lantern slides 

 illustrating the various processes used in manufacturing optical glass, 

 together with curves indicating the rapid increase in American pro- 

 duction in 1917 and 1918. 



135TH meeting 

 The 135th meeting of the Academy was held in the Assembly Hall 

 of the Cosmos Club, the evening of Friday, April 4, 1919, the occasion 

 being an address by Lieut. Col. Byron C. Goss, U. S. A., Chief Gas 

 Officer, Second Army, A. E. F., entitled Gas warfare at the front. The 

 lecture was devoted principally to the military features of gas offense 

 and defense, as experienced by the American Army in 191 8. At this 

 stage of the war reliance was placed mainly on gas shell, and the gas 

 cloud, which was the method by which gas warfare was introduced in 

 1915, was very little used. The use of toxic shell may be divided into 

 three periods. From May, 191 5 to July, 191 6 only lachrymatory shell 

 were used. Phosgene and chlorpicrin shell, intended to produce cas- 

 ualties, came into increased use from July, i9i6toJuly, 191 7. With 

 the latter date began the use of the so-called "mustard gas." The 

 tactical handling of gas shell depends on the object to be accomplished, 

 whether the production of casualties or the neutralization of troops. 

 Details of tactics and of shell design were ably discussed by the lec- 

 turer and were illustrated with lantern slides. The lecture closed with 

 the presentation of some new moving pictures showing the use of 

 thermit bombs and smoke clouds and the handling of gas shell by 

 American artillery at the front in the autumn of 191 8. 



136TH MEETING 

 The 136th meeting of the Academy was held in the Assembly Hall 

 of the Cosmos Club, the evening of Thursday, May 15, 1919. An 

 address was delivered by Prof. John C. Merriam, Acting Chairman 

 of the National Research Council, entitled Cave hunting in California. 

 The discovery of prehistoric stone implements supposed to be from 

 the auriferous gravels of California aroused interest some years ago 

 in the question whether man was present on the West Coast during 

 Pliocene or Pleistocene time. The lecturer outlined his early studies 

 of the problem through the examination of auriferous gravels, river 

 terrace gravels, and caves, illustrating the story with many lantern 

 slides of California caves. Among the localities where significant 

 material was obtained were Mercer's Cave in Calaveras County, Haw- 

 ver's Cave and the Robbers' Cave in the American River valley, and 

 Potter Creek Cave and Sarnwel Cave on the McCloud River. Many 

 new species of extinct Pleistocene animals were found in the course of 

 the explorations, but no absolutely certain evidence has been discovered 

 of the existence of man in California before the present epoch. The 

 lecture was discussed by several members of the Academy. 



William R. Maxon, Recording Secretary. 



