GEOPHYSICAL LABORATORY.^ 



Robert B. Sosman, Acting Director. 



Since the date of the last annual report (October 1, 1918), the war 

 has been brought to an end by the armistice of November 1918, and 

 most of the Laboratory's staff has been released from war work to 

 return to the researches interrupted in 1917. 



This release could not be immediately accomplished, however, for 

 two reasons. First, there remained in the possession of the Laboratory 

 a considerable amount of new data, both technical and scientific, 

 bearing on the war problems in which the staff had been engaged, 

 which needed to be written up in form for publication. Second, 

 there were several lines of research which by an additional few months' 

 work could be made to yield valuable results, whereas if abandoned 

 where they stood they would represent a complete loss of the existing 

 experimental preparations and incomplete data. 



A part of the work of the year may thus be considered as salvage 

 work following the disturbance of conditions due to the war. The 

 principal war work of the Laboratory was concerned with directing 

 the manufacture of optical glass for Army and Navy instruments. 

 The scientific and technical results of the optical-glass work are for 

 the most part being published as a series of papers on the manufacture 

 and properties of optical glass, of which 21 numbers have been pub- 

 lished or are in press. ^ 



A second war problem was concerned with the fixation of nitrogen 

 for the manufacture of explosives. Experimental work on the chemis- 

 try of the so-called Bucher cyanide process and the Haber or synthetic 

 process was begun in the summer of 1918, and had therefore not 

 proceeded far when the war ended. A few papers on the chemistry 

 of these processes will put on record the facts of scientific interest 

 obtained in connection with the problems investigated.^ 



VOLCANO STUDIES. 



Investigations of the phenomena of active volcanoes were begun 

 by the Laboratory in 1911 at Kilauea, Hawaii, and reports of the 

 work there have been included in several previous Annual Reports.^ 

 In 1914 the v/ork was extended to several of the ItaUan volcanoes 

 (Vesuvius, Etna, Stromboli, Vulcano), and observations thereon have 

 been continued, though under considerable difficulties and limitations, 

 during the war.^ 



In 1915, observations were made on the volcano of Lassen Peak, 

 in California, which began explosive eruptions in 1914, after a period 

 of quiescence extending back of historic records, and continued its 



^ Situated in Washington, District of Columbia. 



2 See abstracts (1), (2), (3), (13), (14), (15), (17), (19), (20), (25), (26), (27), (29), (32), (38), 

 (39). (40), and (44), below. 



' See abstracts (10) and (34) below. Other papers will appear later. 



* Year Book 10, 91 (1911); 11,99,100(1912); 12,127-129(1913); 15,141-143(1916); 18, 134 

 (1917). 



» Year Book 16, 137-140 (1917). 



153 



