CONTEXTS. 



NumlDer 243. 



Page 



Art. XX. — Gold-colored Allotropic Silver; by M. Carey 



Lea. Parti. With Plates XI-XIII 179 



XXL— The Flora of the Great Falls Coal Field, Montana; 



by J. S. Newberry. With Plate XIV 191 



XXII." — High Level Shores in the region of the Great Lakes, 



and their Deformation ; by J. W. Spexcer 201 



XXIII. — Notes on Ferro-Goslarite, a new variety of Zinc 



Sulphate; by H. A. Wheeler _ 212 



XXIV. — Composition of Pollucite and its Occurrence at 



Hebron, Maine ; by H. L. Wells 213 



XXV.— The Volumetric Composition of Water; by E. W. 



Morley 220 



XXVI. — Intensity of Sound : A Reply to a Critic ; by C. K. 



Wead 232 



XXVIL— The Fireball in Raphael's Madonna di Foligno; 



by H. A. Newton _._ 235 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics. — Dead Space in Chemical Reactions, Liebreich: New 

 Principle of determining Molecular Masses, Neknst, 239. — Occurrence of free 

 Fluorine in Fluorite, Becquerel and Moissan. 240. — Chemical condition of 

 Iodine in its Solutions. Gautier and Charpy: Properties of Carbon produced 

 from Cyanogen, P. and L. Schutzenberger, 241. — Principles of General Or- 

 ganic Chemistry, Hjelt : Photographic action of Electromagnetic Waves, yon 

 Dobrzynski : Measurement of Dielectric Constants by means of Hertz's Phe- 

 nomenon, Lecher, 242. — Limit of Solar Spectrum m the Ultra Yiolet, Simony: 

 Recent progress in Spectrum Analysis, Rowland, 243. 



Geology and Mineralogy. — Discovery of fish remains in Lower Silurian Rocks, 

 C. D. Walcott: Burrows and Tracks of Invertebrate Animals in Palaeozoic 

 Rocks, J. W. Dawson, 245.— Annual Report for 1 889 of the Geological and 

 Natural History Survey of Minn.. N. H. \Yinchell, 246. — Remarks on the 

 Perisomic Plates of the Crinoids, C. R. Keyes, 247. — Bulletins 2 and 3 of the 

 Geological Survey of Missouri. A. TVinslow: Second Geological Survey of 

 Pennsylvania : Geological Survey of New Jersey : Group of volcanic rocks 

 from the Tewan Mountains, N. M., J. P. Iddixgs, 248.— Elementary Geology, 

 C. Bird: Allgemeine und Chemische Geologie, J. Roth: Black Rutile from 

 the Black Hills, W. P. Headden, L. Y. Pirsson, 249.— Tin in Central Texas, 

 T. B. Comstock: Brief notices of some recently described Minerals, 251. — Dia- 

 monds in Wisconsin, G. F. Kunz : Native Nickel of terrestial origin, A. Sella, 

 252. — Index der Krystallformen, Y. Goldschmldt, 253. 



Botany and Zoology. — Recherches sur la croissance terminale de la tige des phan- 

 erogames, H. Doultot, 253. — Typical Elms and other trees of Massachusetts, 

 0. W. Holmes, L. L. Dame. H. Brooks : Leber die Balken in den Holzelemen- 

 ten der Coniferen, C. M tiller, 254. — Cultures experimentales dans les Alpes et 

 les Pyrenees, G. Bonnier, 255. — Insecta, A. Hyatt and J. M. Arms, 256. 



Miscellaneous Scientific Intelligence. — Fifth International Congress of Geologists: 

 Alabama Industrial and Scientific Society: Transactions of the Meriden Scien- 

 tific Association: A Move for Better Roads, L. M. Haupt, 257. — Die Cordillere 

 von Merida, W. Sievers: Krystallographisch-Chemische Tabellen: Copley 

 Medal: Ostwald's Klassiker de/exakten Wissenchaften, 258. 



Obituary. — James Croll, 258. 



