proceedings: geological society 155 



Mr. Herschel stated that an accuracy of 5 per cent is sufficient for 

 technical purposes. In investigating efflux viscosimeters he has found 

 a modification of Griineisen's diagram very helpful. Plot as ordinates , 



— and as abscissas Ji — . If the commonly accepted Ubbelohde 



form of equation were correct, we would have a straight line cutting the 



X-axis at a distance — = — from the origin, where (I + X) is the effective 



32Z 

 length of capillary, and making an angle whose tangent is — 7 with 



ma . 



the X-axis; m is the kinetic-energy coefficient which is 1.12 according 



to Boussinesq. Mr. Herschel finds that m is variable when a certain 



velocity is exceeded. 



INFORMAL COMMUNICATION 



Mr. L. A. Bauer discussed Some corresponding changes in solar 

 radiation, terrestrial magnetism, and astronomy . With the aid of lan- 

 tern slides, striking similarities were shown to exist between the follow- 

 ing 3 curves: (1) Curve of changes in the solar constant, 1905-1914; 

 (2) curve of anomalies in the regular^ progresing secular variation 

 of the earth's magnetic field, 1905-1913; and (3) curve of mean irregu- 

 larities in motion of Mercury, Venus, the moon, and the earth, 1905- 

 1913. Astronomers having exhausted the possibilities of explaining 

 the outstanding astronomical motions by gravitational causes, are 

 now seeking for some connection with effects arising from possible inter- 

 acting magnetic fields of planets. Inquiries received at various times 

 from astronomers, notably from the late Professor Newcomb, have led 

 the speaker to undertake an examination into the various questions 

 involved. As the first step, he has established a tentative formula 

 which gives the magnetic field strength of the sun within 10 per cent 

 of Hale's provisional value, and shows that a magnetic field possibly 

 to be associated with Jupiter may have a strength almost that of the 

 sun, namely, about 68 times that of the earth. 



The Chair expressed to Mr. Bingham the thanks of the Society for 

 his most interesting communication. 



J. A. Fleming, Secretary. 



THE GEOLOGICAL SOCIETY OF WASHINGTON 



The 300th meeting was held in the lecture room of the Cosmos 

 Club on November 24, 1915. 



informal communications 



D. F. Hewett: Manganese deposits in Virginia. Among six de- 

 posits examined five showed a striking relationship to topographic 

 features. The deposits lie at the base of the Blue Ridge, where the 

 Tertiary plain merges with the hills, and occupy old river channels 



