CONTEXTS 



Page- 



Art. XL — Observation of Sudden Phenomena ; by S. P. 



Langxey _ _ 93 



XII. — Spectro-photometric Comparison of Sources of Ar- 

 tificial Illumination ; by Edward L. Nichols and Wil- 

 liam S. Fraxklin 100 



XIII. — Possibility of Hemihedrism in the Monoclinic Crystal 

 System, with especial reference to the Hemihedrism 

 of Pyroxene; by George H. Williams 115 



XIV. — Earlier Cretaceous Rocks of the Northwestern portion 



of the Dominion of Canada ; by George M. Dawson 120 



XV. — A new occurrence of Gyrolite ; by F. \V. Clarke.. 128 



XVI. — Action of Light on Allotropic Silver ; by M. Carey 



Lea "... 129 



XVII. — Certain Porphyrite Bosses in Northwestern New 



Jersey ; by J. F. Kemp .. 130 



XVIII. — Great lava flows and intrusive trap sheets of the 



Newark system in New Jersey ; by Nelson H. Darton 134 



XIX. — Recent Explorations in the Wappinger Valley Lime- 

 stones and other formations of Dutchess Co., N. Y. ; by 

 W. B. Dwight. (With Plate VI.) 139 



XX. — Silicic Acids; by George F. Becker _. 154 



XXI. — Appendix. — Notice of Gigantic Horned Dinosauria 



from the Cretaceous ; by O. C. Marsh 173 



XXII. — Discovery of Cretaceous Mammalia, Part II ; by 



O. C. Marsh. (With Plates VII and VIII.). ... 177 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physic*. — Vapor Deusity of hydrogen fluoride, Thorpe aud 

 Hambly. 157. — Decomposition of Potassium chlorate by heat. McLeod, 158. — 

 Synthesis of Formic aldehyde, Jahn, 159. — Identity of Seminose and Mannose. 

 E. Fischer and Hirschberger: Synthesis of Uric acid, Behrend aud Roosex : 

 Crystallized Tungsten, H. N. Riddle, 160. — Influence of Solar radiation on Elec- 

 trical phenomena. S. Arrhenius, 161. — Disruptive discharges in gases, M. 

 Wolf: Selective reflection of Metals, H. Rubens, 163. 



Geology and Mineralogy. — Tertiary Volcanoes of the Western Isles of Scot- 

 land, J. W. Judd, 163. — Genus Tubicaulis of Cotta, G. Stenzel: Faune du 

 Calcaire d'Erbray (Loire Inferieure), C. BarroiS: Notes on Epidote and Hanks- 

 ite. C. Bodewig, 164. — Plattnerite from Idaho, J. D. Hawkins and E. W. Haw- 

 kins, 165. — The Minerals of New South Wales, etc.. A. Liversidge : Eighth 

 Annual Report of the State Mineralogist of California, W. Irelax, 166. 



Botany and Zoology. — Beitrage zur Kenntniss der Oxidationsvorgange in lebenden 

 Zellen, Pfeffer: Biologia Central- Americana, Hemsley, 166. — A Hand-Book 

 of Cryptoganiic Botany, A. W. Bennett, 168. — Bathy metric conditions as to 

 growing corals and other species of Tizard and Macclesfield Banks, in the 

 China Sea. W. TJ. Moore and P. W. Bassett-Smith : The Coral Reefs of the 

 Hawaiian Islands, A. Agassiz : Fisheries and Fishing Industries of the United 

 States, G. B. Goode, 169. — Darwinism, A. R. Wallace, 170. 



Astronomy.-^- Researches on the Spectrum, Visible and Photographic, of the 

 Great Nebula in Orion, Hoggins, 170. 



Miscellaneous Scientific Intelligence. — Elizabeth Thompson Science Fund : The 

 Assayer's Manual, B Kerl and F. L. Garrison, 172. 



Obituary. — John Percy: Maria Mitchell. 



