CONTENTS. Vll 



Number 41. 



Page 



Art. XXXIV. — Some Experiments with Endothermic 



Gases; by W. G. Mixter.._. .__ 323 



XXXV. — Hypothesis to explain the partial non-explosive 



Combination of Explosive Gases and Gaseous Mixtures ; 



by W. G. Mixter 327 



XXXVI. — Occurrence of Paleotrochis in Volcanic Rocks in 



Mexico; by H. S. Williams 335 



XXX VIL— Origin of Paleotrochis ; by J. S. Diller 337 



XXXVIII. — Association of Argillaceous Rocks with Quartz 



Veins in the Region of Diamantina, Brazil; by O. A. 



Derby __* „ 1 343 



XXXIX.— Goldsohmidtite, a New Mineral ; by W. H. Hobbs 357 

 XL. — Hydromica from New Jersey; by F. W. Clarke and 



N. H. Darton . -. 365 



XLI. — Powellite Crystals from Michigan; by C. Palache.. 367 

 XLII. — Volatilization of the Iron Chlorides in Analysis, and 



the Separation of the Oxides of Iron and Aluminum ; by 



F. A. Gooch and F. S. Havens 370 



XLIII. — Descriptions of imperfectly known and new Actini- 



ans, with critical notes on other species, V; by A. E. 



Verrill _ 375 



XLIV. — Preliminary Note as to the Cause of Root-Pressure ; 



by R. G. Leayitt___ ...„__ ..- 381 



XLV. — Study of Some American Fossil Cycads. Part III; 



by G. R. Wieland. (With Plates VIII-X.) 383 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — Low Temperature Experiments, Hempel, 392. — Reduc- 

 tions in Presence of Palladium, Zelinsky: Properties of Metallic Calcium, 

 Moissan, 393. — New Bases from Strychnine, Tafel: History of Physics in its 

 Elementary Branches including' the Evolution of Physical Laboratories, E. 

 Cajori, 394. — Electrolytic Interrupter, A A. C. Swinton: Measurement of slow 

 electrical oscillations, W. Konig, 395. — Electric waves on wires, W. D. Cool- 

 idge: Absorption of the X-rays by air: Optischen Instrumente der Firme R. 

 Euess, C. Leiss, 396. 



Geology and Natural History — Note on a Bridger Eocene Carnivore, 0. C. Marsh : 

 Age of the Franklin White Limestone of Sussex County, N. J., J. E. Wolff 

 and A. n. Brooks, 397. — West Virginia Geological and Economic Survey: 

 Alabama Geological Survey, W. B. Phillips : Development of Lytoceras and 

 Phylloceras, J. P. Smith : Pre-Cambrian Igneous Rocks of the Fox River Val- 

 ley, Wise, S. Weidman, 398. — West Virginia Geological Survey, I. C. White: 

 New and interesting olivine-melilite-leucite rock, V. Sabatini, 899. — Deuxieme 

 Memoire sur les Algues Marines du Groenland, L. K. Rosenving-e : Mono- 

 graphic des Caulerpes, A. W. Bosse, 400. — Dispositione Delesseriearum, J. G-. 

 Agakdh, 401. 



Miscellaneous Scientific Intelligence — National Academy of Sciences, 401. — Annual 

 Report of the Board of Regents of the Smithsonian Institution, to July, 1897 : 

 Harper's Scientific Series, 402. 



Obituary— Dr. G-ustav Wiedemann, 402. 



