TEN-VOLUME INDEX.— Mention is again called to the Index to 

 Vols. XLI-L, issued in January. Those wishing should order now, as 

 the edition is limited ; price 75 cents. 



CONTENTS. 



Page 



Art. XXIX.— The Morphology of Triarthrus; by C. E. 



Beecher. (With Plate VIII) 251 



XXX. — Examination of the arguments given by Neumayr 

 for the existence of climatic zones in Jurassic times ; by 

 A. E. Ortmann... _ 257 



XXXI. — Occurrence of Theralite in Costa Rica, Central 



America; by J. E. Wolff 271 



XXXII. — Metamorphism of a Gabbro occurring in St. Law- 

 rence County, N. Y.; by C. H. Smyth, Jr. .. 273 



XXXIII. — Notes on Glacial Gravels, in the Lower Susque- 

 hanna Valley; by H. B. Bashore _. 281 



XXXIV. — The Bearpaw Mountains, Montana. First Paper; 



by W. H. Weed and L. V. Pirsson 283 



XXXV. — Pleistocene Marine Shore-Lines on the South Side 



of the St. Lawrence Valley ; by R. Chalmers . _ 302 



XXXVL— Occurrence of Free Gold in Granite; by G. P. 



Merrill _ . _ . _ 309 



XXXVII.— Theory of the "X-Rays;" by A. A. Michelson 312 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — Some physical properties of argon and helium, Lord 

 Rayleigh : Mixed double halides of platinum and potassium, Herty, 315. — 

 Relative atomic weights of oxygen and hydrogen, J. Thomsen : Synthesis of 

 caffeine, E. Fischer and L. Ach : Free hydrazine, L. de Bruyn, 316 —Practical 

 Inorganic Chemistry, G. S. Turpin: Chemical Experiments, General and Ana- 

 lytical, R. P. Williams: Text Book of Gas Manufacture for Students, J. 

 Hornby: Methods of determination of Dielectric Constants, W. Nernst, 317. — 

 Dielectric Resistance, P. Drude : Index of refraction and reflective power of 

 water and alcohol for Electric Waves, A. D. Cole : Rontgen Rays, J. J. Thom- 

 son, 318. — Experiments with the Rontgen Rays, Doelter: Elements of Phys- 

 ics; A College Text-book, E. L. Nichols and* W. S. Franklin, 319. 



Geology and Natural History — Contributions to the Cretaceous Paleontology of 

 the Pacific Coast, T. W. Stanton, 320. — Contribution a l'etude des lapies, M. 

 Emile Chaix: Geographical distribution of marine animals, 321. — Charles 

 Lyell and modern Geology, T. G. Bonney : Beitrage zur Geophysik, G. Ger- 

 land, 322. — Structure-Planes of Corundum and some Massive Minerals (simple 

 rocks) from India and Australia, J. W. Judd: Remarkable phosphoresence in 

 Wollastonite, W. F. Hillebrand, 323. — Propagation of the sugar-cane, J. H. 

 Wakker: Systematic arrangement of Australian Fungi, together with Host- 

 Index and List of Works on the subject, D. McAlpine, 324. — Der Reis-Brand 

 und der Setaria-Brand, 0. Brefeld, 325.— rEntwickelung des Peritheciums bei 

 Sphaerotheca Castagnei, R. A. Harper, 326. 



Obituary — Dr. Johann Muller, 326. 



Miscellaneous Scientific Intelligence— Catalogue of Scientific Papers (1874-1883), 

 compiled. by the Royal Society of London: Yellowstone National Park, H. M. 

 Chittenden: Mechanics and Hydrostatics: R. T. Glazebrook, 327. — Consti- 

 tution and Functions of Gases, the Nature of Radiance, and the Law of Radia- 

 tion, S. J. Corrigan: Algebra for Beginners: Introduction to the Algebra of 

 Quantics, E. B. Elliott: Problems in Differential Calculus, W. E. Byerly: 

 Plane and Solid Geometry, W. W. BEMANand D. E. Smith: Computation Rules 

 and Logarithms with Tables of other useful Functions, S. W. Holman, 328. 



