1897.] NEW YORK ACADEMY OF SCIENCES. 317 



Special Meeting of the Section of Geology and Mineralogy. 

 Aiml 23, 1897. 



The Section met in the Law School lecture room of Co- 

 lumbia University, Professor J. F. Kemp, Chairman, presiding- 

 About 125 persons present. 



The minutes of the previous meetinor were omitted. The 

 meeting was a joint one with the New York Microscopical So- 

 ciety and the New York Mineralogical Club. 



Professor F. C. Van Dyck, of Rutger's College, briefly ex- 

 plained his improved apparatus for projecting microscopic sec- 

 tions of rocks and minerals with polarized light, using the arc 

 lantern. 



The lantern was then set in operation and large series of thin 

 sections of rocks were thrown upon the screen and were de- 

 scribed b}' Mr. John H. Caswell. 



When the projections of the thin sections were concluded, a 

 vote of thanks was unanimously passed to Messrs. Yan D3^ck 

 and Caswell. 



The Academy then adjourned. 



R. E. Dodge, 

 Secretary of Section. 



April .'50, 1897. 



The regular public lecture for April was delivered by Mr. 

 William Niven on " Recent Archeologicai Explorations in the 

 State of Guerrero, Mexico." About forty persons were present. 



At the conclusion of the lecture a vote of thanks to Mr. Nevin 



was passed. 



J. F. Kemp, 



Secretary. 



Regular Business Meeting, May 3d, 1897. 



The Academy met with President Stevenson in the chair; 

 twenty-five persons present. The minutes of the last meeting 



