Chromium, _Vauquelin's_ process for obtaining, xxi, 375. ----, on the combinations of, _A. A. Hayes_, xiv, 136. ---- oxide, crystals of, xxviii, 396. ----, sulphate of oxide, _M. E. Kopp_, xlviii, 189. Chronometers, remarks on, xxix, 297. ----, _Dent's_ improvements, xliv, 161. ----, errors of, _E. J. Dent_, xlv, 83.^f ----, sea and land rates of, _Parkinson_ and _Frodsham_, xxvi, 121. ----, rate varied by the density of the medium containing, x, 185. ----, purification of olive oil for, xx, 166. ----, new compensation-balance for, _E. J. Dent_, xlv, 83.^f ----, glass balance for, xxxii, 330.^f Chrysoberyl of Haddam, analysis of, _H. Seybert_, viii, 105. ----, in Connecticut, ii, 142, 240; iv, 52. ----, in New York, iv, 37. Chrysoprase, viii, 234; xvii, 353. _Churchill, S._, notice of a double fish, xxvi, 116.^f Chyometer, mode of determining specific gravities with, xi, 126.^f Cicada septendecim, or seventeen year locust, habits of, xiii, 224. ---- ----, account, of, _S. P. Hildreth_, xviii, 47.^f ---- ----, remarks on, _D. Thomas_, xxi, 188. Cinchona, on the different kinds of bark confounded with, _De Candolle_, xvii, 388. ----, bark, experiments on, _G. W. Carpenter_, ix, 363. Cinchovatine, xlvii, 196. Cinnabar in Michigan, i, 433; ii, 170; xxxvii, 185. Cinnamon stone of Ceylon, analysis of, xiv, 204. Cipher, new diplomatic, iv, 377. Circulation of the blood, regulation of, _T. J. Aikin_, xxviii, 79. ---- in plants, xix, 393. ---- ----, _E. Emmons_, xxvi, 99. _Cist, Z._, mines of anthracite about Wilkesbarre, Pa., iv, 1. _Cist, J._, on the Melolontha or May bug, viii, 269.^f Cisterns for water, mode of constructing, xxv, 301. Citric acid from gooseberries, xvi, 385. Citricic acid, _S. Baup_, xxxiv, 206. Civilization, connection of, with mental aberration, xxii, 379. Clam, eatable, of N. Y., facts regarding, x, 287. _Clark, D. A._, singular appearances of snow and hail, ii, 132. _Clark, S._, on the infinite divisibility of a finite quantity of matter, ix, 356. ----, notice of, xli, 217.^f _Clarke, E. M._, magnetic electrical rotating machines by, xxxiii, 213.^f ----, electrepeter by, xxxiii, 224.^f _Clary, R. E._, parhelia seen at Green Bay, xxviii, 304.^f Classification, chemical, remarks on, _O. W. Gibbs_, xlix, 384. ----, ----, _R. Hare_, xxvii, 63; xxxii, 260. ----, mineral, remarks on, _J. D. Dana_, xlvi, 374. ---- of clouds, _E. Loomis_, xli, 325. Clay of Pownal, Vt., xii, 298. ----, pipe, in New Jersey, ii, 198. ----, potter's, in Massachusetts, i, 344. ----, for sculptors, xxiv, 200. Cleaveland's Mineralogy, review of, i, 35, 308. ---- ----, second edition announced, ii, 375. Cleavelandite, (Kieselspath,) a variety of albite, vii, 370, 390.