568 
PHILOSOPHICAL SOCIETY OF WASHINGTON. 
small attendance, due to the inclemency of the weather, the 
reading of the papers upon the program be deferred until the 
next meeting. 
370th Meeting. April 25, 1891. 
Vice-President Gilbert in the chair. 
Thirty-three members present. 
The election and qualification of Mr. W. K. Carr as a mem¬ 
ber of the Society was announced. 
Two papers, illustrated by a series of specimens, were read 
On the Characteristic Radiate Growth in Acid Lavas, the first 
by Mr. W. Cross, entitled Constitution and Origin of Spherulites 
(published in this volume, pp. 411-444), and the second by Mr. 
J. P. Iddings, entitled Spherulitic Crystallization in Obsidian 
(published in this volume, pp. 445-464). 
Remarks were made by Messrs. Abbe, Gilbert, Littlehales, 
Iddings, and Cross. 
Mr. R. S. Woodward gave a review of Tisserands Traite de 
Mecanique Celeste. 
Published in the Annals of Mathematics, vol. 6, No. 1. 
Remarks were made by Messrs. Kummel and Woodward. 
371st Meeting. May 9, 1891. 
Vice-President Gilbert in the chair. 
Twenty-one members present. 
The death of Prof. Julius E. Hilgard, one of the founders of 
the Society, was announced. It occurred at his residence in this 
city on May 8. 
Mr. F. W. Clarke made a communication on A Theory of the 
Mica and Chlorite Groups. 
To be published in the American Journal of Science early in 
1892. 
