CONTENTS. 



Number 21. 



Page 



Art. XIX. — Principal Characters of the Protoceratidse ; by 



O. C. Marsh. Parti. (With Plates II- VII.) 165 



XX.— Theory of Singing Flames ; by H. V. Gill 177 



XXI. — Electrical Discharges in Air; by J. Trowbridge. . . 190 



XXII. — Oscillatory discharge of a large Accumulator; by 



J. Trowbridge __. _.._ 194 



XXIII. — Jura and Neocomian of Arkansas, Kansas, Okla- 

 homa, New Mexico and Texas ; by J. Marcou 197 



XXIV. — Pithecanthropus erectus; by L. Manouvrier. 



Translated by George Grant MacCurdy.. 213 



XXV. — Titration of Sodium Thiosulphate with Iodic Acid ; 



byC. F. Walker. 235 



XXVI. — Solarization effects in Rontgen Ray Photographs; 



by W. L. Robb. (With Plates VIII-X.) 243 



XXVII. — Cape Fairweather Beds, a new marine Tertiary 



Horizon in Southern Patagonia ; by J. B. Hatcher 246 



SCIENTIFIC INTELLIGENCE. 



Natural History — New Series of Contributions from the Gray Herbarium of Har- 

 vard University, No. XI, J. M. Greenman : Synoptical Flora of North Ameri- 

 ca, Vol. 1. Part I, 249.— Illustrated Flora of the Northern United States, Can- 

 ada, and the British Possessions, N. L. Britton and A. Brown: Guide to the 

 Genera and Classification of the North American Orthoptera found north of 

 Mexico, S. H. Scudder: Das Tierreich, E. Hartert, 250. 



Miscellaneous Scientific Intelligence— American Association for the Advancement 

 of Science, 250. — Transactions of the American Microscopical Society, 256. 



