514 
Porosity of solid bodies for the light 
ether, Zehnder, 70. 
Pratt, J. H., optical properties of 
lithiophilite and triphylite, 387. 
Pupin, M. I., electro-magnetic theory, 
326, 
R 
Ramsay, argon and helium, 264. 
Reyer, Geologische experimente, 74. 
Reynolds, W. G., reduction of the 
acids of selenium by hydriodie acid, 
204. 
Robinson, B. L., contributions from 
the Gray Herbarium of Harvard 
Univ., 135. 
Rock conductivity for heat, Kelvin 
and Murray, 419; Peirce and Will- 
son, 435. 
Rock specimens, directions for collect- 
ing, 349. 
Rocks, study of, Fletcher, 426. 
Rocks— 
Complementary and radial dikes, 
Pirsson, 116. 
Composite dikes of Arran, Judd, 
270. 
Gneisses of the Laurentian, Adams, 
64. 
Eruptive rocks of Christiania, 
Brogger, 348, 
Marble, thermal conductivity, 435. 
Minette, 313. 
Phonolites, etc., of Montana, Pirs- 
son, 394; Weed, 506. 
Syenite, Montana, 470. 
Quartz diorite porphyrite, 311. 
Quartz syenite porphyry, 311. 
Shonkinite, Montana, 473. 
Yogoite, Montana, 473. 
Rothwell, R. P., Mineral Industry in 
U.S., 427. 
Russell, I. C.. Lakes of North America, 
006. 
Ss 
Scientific Societies’ publications, uni- 
formity of size of pages, 431. 
Scoville, W.S., reduction of selenic 
acid by potassium bromide in acid 
solution, 402. 
Sherzer, W. H.. native sulphur in 
Michigan, 246. 
Silica, Native, Wright, 274. 
INDEX. 
Silicates, constitution, Clarke, 2'74. 
Smith, J. E.. metamorphic series of 
the Shasta region of California, 346. 
Stevens, W. LeC., recent progress in 
optics, 277, 377. 
Story-Maskelyne, N. 
Crystallogra- 
> 
phy, 507. 
T 
Temperatures, measurements of high, 
Holborn and Wien, 502. 
underground, Agassiz, 503. 
Thunderstorms, origin, Smith, 4380. 
Trinidad, Pitch Lake of, Peckham, 
38. 
Trowbridge, J., velocity of electric 
waves, 104. 
U 
United States, geological atlas, 504 ; 
geol. survey, 425. 
V 
Von Zittel, K. A., Grundziige der 
Palzontologie, 268. 
WwW 
Waldo, F., diurnal rise and fall of the 
wind in the U. S., 285. - 
Weed, W. H., igneous rocks of Mon- 
tana, 309, 467; phonolitic rocks 
from Montana, 506. 
Wells, H. L., compounds containing 
lead and extra iodine, 21; double 
salts of cesium chloride, ete., 249 ; 
ammonium cuprous double halogen 
salts, 390. 
Wiley, H. W., Agricultural Analysis, 
431. 
Willson, R. W., thermal conductivi- 
ties of marble and slate, 435. 
Wind in the U. S. diurnal, rise and 
fall, Waldo, 239. . 
Wood, R. W., demonstration of caus- 
tics, 301. 
Woodworth, J. B., dinosaur tracks in 
New Jersey, 481. 
Wright, B., Native Silica, 274. 
