CONTENTS. 



Page 

 Art. XXV. — The Gulf of Mexico as a Measure of Isostacy; 



by W. J. McGee ._ ...... Ill 



XXVI.— Persistence of Vision ; by E. S. Ferry 192 



XXVII. —Kilauea in April, 1892; by S. E. Bishop 207 



XXVIII. — The Devonian System of Eastern Pennsylvania ; 



by C. S. Prosser . . .. -. 210 



XXIX. — Csesium-Mercuric Halides; by H. L. Wells 221 



XXX. — Relations of the Lanrentian and Huronian on the 



North Side Of Lake Huron ; by A. E. Barlow ... 236 



XXXI. — Some Convenient Forms of Laboratory Apparatus; 



by F. A. Gooch . ..239 



XXXII. — Note oh the change of electric conductivity ob- 

 served in rock magmas of different composition on pass- 

 ing from, liquid to solid; by Carl Barus and J. P. 

 Iddings '. . .-.....- 242 



XXXIII. — Estimation and Dehydration of Silver Oxide; 



by M. Carey Lea __'... . : 249 



SCIENTIVO INTELLIGENCE. 



Chemistry and Physics — Phenomena of Coal-dust Explosions, Thorpe, 250'.= — 

 Certain new forms of Carbon, • Luzi, 251.— Quinite, the simplest' Sugar of the 

 Inosite group, Baeyer: Eelation between the Color of Compounds and their 

 Chemical Constitution, Schutze, 252. — Free Hvdroxvlamine, Lobry de Bruyne : 

 Physical and chemical phenomena under the influence of very low "temperatures, 

 - M. Raoul Pictet, 253. — New method of determining' the specific inductive 

 capacity of a dielectric, F. T. Tbquton and TV. E. Lilly: Action of the Electric 

 discharge on Gases and Vapors, C. Ludeking: Ratio between the Electromagtic 

 and Electrostatic Units, M. H. Abraham : Influence of Electrification on Cloud 

 Condensation, J. Aitken, 254. — Thermal variation of viscosity and of electrolytic 

 resistance, C. Barus : Outlines of Theoretical Chemistry, L Meyer, 255. — 

 Theoretical Mechanics, J. Spencer: Negativ-Retouche nach Kunst- und Natur- 

 gesetzen, Hans Arnold, 256. 



Geology and Mineralogy — Upraised Coral Islands off New Guinea, 256. — Origin of 

 Igneous Rocks, J. P. Iddings, 257. — Bulletin of the Philosophical Society of 

 Washington, Button on Isostacy, 258. — Siliceous bed consisting of Diatoms. 

 Radiolarians and Sponge-spicules in New Zealand : Preliminary Catalogue of the 

 systematic Collections in Economic Geology and Metallurgy in the U. S. 

 National Museum, F. P. Dewey : Palaeontology of the Cretaceous formation on 

 Staten Island, A. Hollick, '259. — Untersuchungen uber fossile Holzer Schwe- 

 dens, H. Conwentz: Penfieldite, a new species, F. A. Genth, 260. — Brief 

 notices of some recently described minerals. 261. 



Miscellaneous Scientific Intelligence — Transactions of the Wisconsin Academy of 

 Sciences, Arts and Letters: Dictionary of Altitudes in the United States, H. 

 Gannett, 262. •' 



