VI CONTENTS. 



Number 202. 



Page 

 Art. XXXI. — Emission of Electrons by Metals under the 

 Influence of Alpha Rays ; by H. A. Bumstead and A. 

 G. McGougan 309 



XXXII. — Flashing Arcs : A Volcanic Phenomenon ; by F. 



A. Pereet ..".... 329 



XXXIII. — Comparison of Two Screws ; by C. Barus 333 



XXXIV. — Some Growth Stages in Naticopsis altonensis, 



McChesney ; by G. H. Girty. (With Plate I).. 338 



XXXV. — Sulphides of Zinc, Cadmium, and Mercury ; their 

 Crystalline Forms and Genetic Conditions ; by E. T. 

 Allen and J. L. Crenshaw. Microscopic Study by 

 H. E. Merwin 341 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — Formation of Eed Phosphorus, Stock, Schrader 

 and Stamm : Devitrification of Silica Glass, W. Crookes, 397. — Presence 

 of Formaldehyde in Plants, Curtius and Franzen : Determination of 

 Sulphur in Insoluble Sulphides, T. St. Warunis, 398. — Benzoic Acid as 

 an Acidimetric Standard, G. W. Morey : Ein neuer Fall von Koppelung 

 kurz- und langwelliger Fluoreszenzbanden, M. Gelbke, 399. — Dielonisier- 

 ung von Gasen durch Licht und das Funkenspektrum des Aluminiums 

 im Gebiete der Schumannstrahlen, 400. — Apparent Change in Weight 

 during Chemical Reaction, J. J. Manley, 401. — Torque produced by a 

 Beam of Light in Obliqvie Refraction through a Glass Plate, G. Barlow, 

 403. 



Geology — Sub-Oceanic Physiography of the North Atlantic Ocean, E. Hull, 

 403. 



Obituary — J. T. Gardiner : W. J. McGee : P. C. Freer : H. A. Weber : 

 J. H. Poincare : C. Andre : H. O. Jones : R. Hornes. 



