RECORDS. 627 



SECTION OF ASTRONOMY AND PHYSICS. 



February 6, 1899. 



Section met at 8.30 P. M., Mr. P. H. Dudley, presiding. 



The following program was then offered : 



L. J. R. Hoist, The Influence of the new Jena Glass 

 ON Modern Optics. 



Mr. Hoist gave in his paper a short account of the develop- 

 ment of photography and photographic lenses, and in addition 

 showed a number of photographs taken with some of the stan- 

 dard lenses in regular use, as well as several that were taken by 

 a similar lens of Jena glass. The latter showed much better 

 definition over a broader field. A number of micro-photographs 

 were also exhibited, showing that with Jena glass a greater depth 

 of focus is obtained than with ordinary optical glass. 



A general discussion on the paper followed and a vote of 

 thanks to Mr. Hoist was tendered by the Section. 



F. L. Tufts, 

 Secretary pro tem. 



SECTION OF BIOLOGY. 



February 13, 1899. 



The following program was offered : 



Francis B. Sumner, Observations on the Germ Layers 

 OF Teleost Fishes. 



Gary N. Calkins, The Evolution of the Karyokinetic 

 Figure. 



Frederic S. Lee, The Cause and Significance of Mus- 

 cle Fatigue. 



Owing to the severe storm on the night preceding it was 

 decided by the Chairman and the Secretaiy, that the meeting be 

 postponed. 



Gary N. Calkins, 



Secretary. 



