230 proceedings: geological society 



thus becomes one of interest not alone to the astronomer but also to 

 the magnetician. 



A brief statement was made with regard to observing parties during 

 the total solar eclipse of October 9-10, 1912, the path of totality of which 

 passes through the northern part of Ecuador and the central part of 

 Brazil . The Department of Terrestrial Magnetism of the Carnegie Insti- 

 tution of Washington is planning to place as many of its South American 

 parties as possible along the belt of totality. The special work to be 

 undertaken will be the necessary observations for testing whether there 

 is an observable magnetic or electric effect during the time of totality. 

 The plans contemplate cooperation with astronomical parties sent out 

 by other organizations. 



Mr. Abbot spoke informally of the variable light transmission for 

 different wave lengths in a spectroscope containing ultra-violet glass, 

 the absorption being different for different wave lengths. 



Mr. Humphreys spoke informally of Subring's observations of the 

 variability in the position of one of the neutral points in sky polarization, 

 and gave an explanation of its three different observed positions 



The 707th meeting of the Society as held on March 23, 1912. Two 

 papers were read: An account of the work of the 26-inch equatorial at the 

 Naval Observatory: Asaph Hall, of the U. S. Naval Observatory. The 

 speaker gave a brief historical account of the 26-inch equatorial telescope, 

 and spoke of the changes that had been made in some of its parts since 

 its installation in 1873. Lantern slides were exhibited illustrating its 

 original and its present mounting in the new observatory. 



The class of work for which the telescope has chiefly been used was 

 mentioned and proposed work with it was outlined. 



A new colorimeter: P. G. Ntjtting, of the Bureau of Standards. See 

 this Journal 2: 183. 1912. 



R. L. Faris, Secretary. 



GEOLOGICAL SOCIETY OF WASHINGTON. 



The 250th meeting was held in the Cosmos Club January 10, 1912, 

 and the following papers were given : General remarks on mines, mining 

 etc. in Peru, Chile and Bolivia. Illustrated. Howland Bancroft. 



Vanadium deposits in Peru. Illustrated. D. F. Hewett. This paper 

 described vanadium deposits in two districts in western central Peru, the 

 Yauli district in which vanadium is a constituent of asphaltite, and the 

 Quisque district in which vanadium is found as the sulphide, associated 

 with vanadiferous bitumens. The two districts are situated on the east 

 slope of the Andes, at altitudes of 15, 300 and 16,200 feet respectively. 



The Yauli deposits are numerous lenses of asphaltite lying parallel 

 to the steeply dipping bedding-planes of Jurassic thin limestones and 

 shales. The largest lens is 550 feet long and 22 feet wide. A dike of 

 igneous rock lies parallel to the bedding planes in the footwall. Chemical 

 data were given which indicated the association of vanadium with the 

 bituminous material. The deposits are not exploited for vanadium at 

 present. 



