CONTENTS 

 Oeiginal Papbbs 



Page 

 Artillery. — The problem of anti-aircraft firing. X. Reillb 465 



Crystallography. The assignment of crystals to symmetry classes. Edgab 



T. Wherry 480 



Botany. — A sketch of botanical activity in the District of Columbia. I. 



P. L. RiCKER 487 



Radiotelegraphy. — Resonance measurements in radiotelegraphy with the 



oscillating audion. L. W. Austin 498 



Abstracts 



Geology ^. 501 



Zoology 503 



Proceedings 



Washington Academy of Sciences 4 . . . . 504 



Philosophical Society of Washington 504 



Scientific Notes and News 508 



