GEOPHYSICAL LABORATORY. 175 



(28) Optical glass and its future as an American industry. Arthur L. Day. J. Franklin 



Inst., 190. 453-472 (1920). (Papers on Optical Glass, No. 26.) 



At the time of the entry of the United States into the World War in April 

 1917, optical glass was being made in tliis country by but one manufacturer. 

 The quahty of the glass was fair, but not comparable with the best European 

 glasses. The maximum production was about 2,000 pounds per month. 

 American requirements for war purposes, including both Army and Navy, 

 were estimated by the General Munitions Board to be about 2,000 pounds 

 per day. 



The three glass-producing countries, England, France, and Germany, for 

 reasons of national interest, chose to maintain the integrity of the national 

 monopoly in optical glass existing in those countries before the war, and even 

 under the pressure of war requirements the technique of optical-glass manu- 

 facture remained shrouded in the deepest secrecy. 



In this emergency the Geophysical Laboratory, because of its experience 

 with silicate solutions, was invited to try, if possible, to discover this tech- 

 nique and to aid in the manufacture of the glass required for fire-control in- 

 struments for all branches of the war ser\ice. This was done in collaboration 

 first with the Bausch & Lomb Optical Company and later with the Spencer 

 Lens Company of Buffalo and the Pittsburgh Plate Glass Company at Char- 

 leroi, Pennsylvania. The problem as confronted by the Laboratoiy consisted 

 mainly in searching out American sources of supply for the purest raw materi- 

 als for the glass and the containing vessels in which it was to be melted. In 

 this it enjoyed the fullest cooperation from the United States Geological Sur- 

 vey and the Bureau of Mines, and many private sources of information. It 

 remained then to ascertain the relation between glass compo.sition and the 

 optical quahties prescribed for particular instruments, and finally to learn 

 the precise conditions necessary for melting these ingredients so as to secure 

 complete homogeneity and a definite composition, and to cool and anneal the 

 finished product to secure physical homogeneity or freedom from strain. 



The work was successful even beyond the most sanguine expectations, and 

 within a period of four months from our entry into the war the limited number 

 of glasses needed by the War and Navy departments could be produced in a 

 quality comparal)le with that which had hitherto been imported. From that 

 time on the problem was chiefly in increasing the plant capacity in the various 

 manufacturing organizations to meet the war requirements. 



The total quantity of glass of optical quahty produced under the direction 

 of the Geophysical Laboratory amounted in all to something over 600,000 

 pounds, being about 97 per cent of the total quantity required and used by 

 the United States Government for war purposes. The remaining 3 per cent 

 was produced in part by the Bureau of Standards Laboratory at Pittsburgh, 

 in part b^^ Mr. Karl Keuffel in the Works Laboratory of the Keuffel & Esser 

 Company at Hoboken. A few hundred pounds were permitted to be im- 

 ported from France and England. No other glass was available to the Gov- 

 ernment for war operations. 



(29) Memorial of George Ferdinand Becker. Arthur L. Day. Bull. Geol. Soc. Amer., 31, 



14-25 (1920). 



A review (with bibhography) of the fife and scientific work of Dr. George F. 

 Becker, for 38 years chief of the Division of Physical and Chemical Research 

 of the United States Geological Survey, and initiator of the researches out of 

 which grew the present organization of the Geophysical Laboratory. 



