CONTENTS 



Page 



Original Papers 



Physics. — On the theory of irreversible time effects. Mayo D. Hersey 149 



Botany. — Notes on the genus Swartzia in Panama and Guatemala. Henry PittiER 155 



Oceanography. — Practical application of the electrical conductivity method of mea- 

 suring sea water salinity. A. L. Thtjras IGO 



Proceedings 



Philosophical Society. . ' 162 



Scientific Notes and News 170 



OFFICERS OF THE ACADEMY 



President: Ali^REd H. Brooks, Geological Survey. 

 Corresponding Secretary: Robert B. vSosman, Geophysical Laboratory. 

 Recording Secretary: WiIvLIAM R. Maxon, National Museum. 

 Treasurer: R. L. Faris, Coast and Geodetic Survev. 



MEETINGS OF NATIONAL ORGANIZATIONS IN WASHINGTON 



April 18-20. The American Geoph^'-sical Union. 



April 20-21. The American Meteorological Society. 



April 22-23. The American Physical Society. 



April 25-27. The National Academy of Sciences. 



May 2-4, The American Society of Mammalogists. 



