GEOPHYSICAL LABORATORY. 173 



The rate of volatilization falls off considerably during a long heating if the 

 glass is not stirred, as a film considerably lower in PbO forms on the sm'face of 

 the melt, into which PbO must diffuse from below before it can escape. The 

 rate of volatihzation of PbO at the temperatures usually employed in optical- 

 glass manufacture would seem from these experiments to be small enough so 

 that variations in refractive index due to volatihzation are not to be expected 

 if the procedure is reasonably constant from melt to melt, but large enough to 

 cause considerable variations in index if the melting schedule is changed. 



(40) War-time development of the optical industry. Fred E. Wright. J. Optical Soc. 



Amer., 2, 1-7 (1919). (Papers on Optical Glass, No. 20.) 



In this paper a brief statement is given of the several factors which were 

 involved in the high-speed production of fire-control instruments for the Army 

 and Nav>'. The development of the manufacture of optical glass and the 

 connection of the Geophysical Laboratory with this problem are described; 

 the rapid increase in the manufacturing capacity of the country for precision 

 optics to meet the urgent demands of the Army and Navj^ is outhned, and 

 attention is directed to the results finally attained which insured an adequate 

 supply of these instruments to June 1919. 



(41) Sights and fire-control apparatus. Fred E. Wright. Chapter VI, pp. 135-147, of 



"America's Munitions, 1917-1918," Report of the Director of Munitions, War 

 Department, Washington, 1919. 



This chapter, which was written by Major Fred E. Wright in collaboration 

 with Colonel H. K. Rutherford, presents a summarized record of the develop- 

 ment of fire-control apparatus during the war, of the difficulties which were 

 overcome in the production of optical glass, and of the conversion of other 

 hues of industry to optical-instrument manufacture. A detailed statistical 

 statement is given of the status of orders for fh'e-control apparatus on Novem- 

 ber 11, 1918 (the time of the signing of the armistice), and also on February 

 20, 1919. 



(42) The oxidation of lava by steam. J. B. Ferguson. J. Wash. Acad. Sci., 9, 539-546 



(1919). 



Under certain conditions steam is capable of oxidizing iron and its lower 

 oxides to magnetite, Fe304, or to ferric oxide, Fe203. This fact has often 

 been quoted as an indication of the probable oxidizing action of steam upon 

 the lava during an eruption. In this paper this reasoning from analogy is 

 subjected to the hght of recent investigations and found wanting. In addi- 

 tion, some experimental results are given which confirm the view that the 

 ferrous iron is not thus oxidized, and wliich indicate that the presence of much 

 ferrous iron in the lava and much steam in the volcanic emanations of Kil- 

 auea are two facts which are in full accord. Several miscellaneous experi- 

 ments are also reported which show that in the experimental study of the 

 chemistry of the lavas careful attention must be paid to the character of the 

 gas phase in contact with the lava if results of value are to be obtained. The 

 bearing of these experiments upon the interpretation of the results ol3tained 

 by pumping gases from rocks at liigh temperatures need only be mentioned. 



(43) George Ferdinand Becker, 1847-1919. Aathur L. Day, Am. J. Sci., 48, 242-245 (1919). 



A review of the life and scientific work of Dr. George F. Becker, for thirty- 

 eight years chief of the Division of Physical and Chemical Research of the 

 U. S. Geological Survej' and initiator of the researches out of which grew 

 the present organization of the Geophysical Laboratory. 



