CONTENTS 



Originai. Papers 



Physics. — A simple substitute for a cathetometer. J. B. Ferguson 285 



Botany. — ^Revision of the true mahoganies (Swietenia). S. P. Blae£ 286 



Abstracts 



Entomology 298 



Chemistry 299 



Analjrtical Chemistry 299 



Phjrsical Chemistry r 300 



Engineering 300 



Geology 301 



Physics 302 



Technology 302 



F*roceedings 



Philosophical Society of Washington 303 



Biological Society 304 



Scientific Notes and News 3" 



