CONTENTS. V 



Number 225. 



Page 



Aet. XXIII. — Feasibility of establishing a Light-wave as 

 the Ultimate Standard of Length; by A. A. Michelson 

 and E. W. Morley 181 



XXIV. — Carboniferous Echinodermata of the Mississippi 



Basin ; by C. R. Ketes 186 



XXV. — Energy Potentialized in Permanent Changes of 



Molecular Configurations ; by C. Barus 193 



XXVI. — Contributions to Mineralogy, No. 44 ; by F. A. 



GrENTH .. 198 



XXVII.— Period of Rotation of the Sun ; by H. Crew 204 



XXVIII.—" Grand Gulf" Formation of the Gulf States; by 



L. C. JOHNSON ._ _.. 213 



XXIX. — Radiant Energy and Electrical Energy ; by J. 



Trowbridge 217 



XXX. — Note on the fossil Spider, Arthrolycosa antiqua 



of Harger ; by C. E. Beecher 219 



XXXI. — Paragenesis of Allanite and Epidote as Rock-form- 

 ing Minerals ; by W. H. Hobbs ... 223 



XXXII. — New locality of the Camptonite of Hawes and 



Rosenbusch ; by F. L. Nason 229 



XXXIII. — Determination of the value of the B. A. Unit of 

 Resistance in Absolute measure, by the method of Lo- 

 renz; by L. Duncan, G. Wilkes and C. T. Hutchinson 230 



XXXIV.— Properties of Allotropic Silver ; by M. C. Lea. . . 237 



XXXV. — Ring Systems and other Curve Systems produced 



on Allotropic Silver by Iodine ; by M. C. Lea 241 



XXXVI. — Notes on some Native Iron Sulphates from Chili; 



by J. B. Mackintosh 242 



SCIENTIFIC INTELLIGENCE. 



Physics. — Electrical Waves in Conductors, Hertz, 246. — Disintegration of Sur- 

 faces by means of the Ultra Yiolet rays, P. Lenabd and M. Wolf, 247. 



Geology and Mineralogy. — Eruption of Baldai-san, in Northern Japan, on July 15, 

 1888, T. Kikuchi, 24*7. — Mastodon or Elephas with fragments of charcoal at 

 Attica, Wyoming Co., N. Y., J. M. Clabke: Illustrations of the Fossil Fishes of 

 the Devonian Rocks of Canada, J. F. Whiteaves: Notices of some recently de- 

 scribed minerals, 249. — Lehrbuch der Mineralogie, C. Hintze, 251. — Mazapilite, 

 ELoenig, 252. 



Botany and Zoology. — Ueber Entstehung und Wachsthum der Zellhaut, E. Zach- 

 arias: Volvox, L. Klein, 252. — Zur Kenntniss der fixen Lichtlage der Laub- 

 blatter, G. Krabbe : Flora, oder Allgemeine botanische Zeitung : Utilization 

 by plants of free atmospheric nitrogen: Monographiaa Phanerogarum Prodromi 

 nunc continuatio, nunc revisio Editoribus et pro parte auctoribus Alphonso et 

 Casimir De Candolle. Vol. Sextum. Andropogoneaa, auctore, E. Hackel, 

 253. — Angewandte Pnauzenanatomie, A. Tschirch: Report on the Mollusca 

 from dredgings of the Steamer "Blake," H. Dall, 254. 



Miscellaneous Scientific Intelligence. — Soaping Geysers, A. Hague, 254. — Proceed- 

 ings of the Colorado Society, Part I : Chemistry of Photography, R. Meldola, 

 255. — Ostwald's Klassiker der exakten Wissenschaften, 256. 



Obituary. — Elias Loomis, 256. 



