CONTENTS 

 Original Papbrs 



Page 



Chemical Crystallography. — Ammonium picrate and potassium trithionate: 

 optical dispersion and anomalous crystal angles. Herbert E. Merwin. . . 429 



Botany. — On the origin of chicle with descriptions of two new species of 

 Achras. H. PiTTiER 431 



Abstracts 



Geology. 439 



Engineering 444 



Metallurgy 445 



Proceedings 



Philosophical Society 447 



Geological Society 45 1 



Scientific Notes and News 454 



