Cohesion, experiments with soap bubbles on attraction of, _J. Henry_, xlviii, 216. Coins, remarks on, and descriptions of some ancient, xxvii, 74. ---- and medals, character and composition of, _J. W. Draper_, xxix, 157. Coir fibre, used for ropes, xxi, 33. Coke, natural, of Virginia, _W. B. Rogers_, xliii, 175. Cold, effects of, ii, 177. ----, artificial, produced by mixed metals, xiii, 171. ----, ----, a freezing mixture for, xii, 195. ----, extraordinary seasons of, _N. Webster_, xxviii, 183. ---- at New Haven in 1766, 1767, xxviii, 183. ---- at Hartford in 1780, xxviii, 186. ----, extreme, at Plattsburgh, N. Y., iii, 366; xi, 195. ---- in Maine, 1817, mercury frozen by, xxxi, 161. ---- on Lake Superior, ix, 395. ---- of the winter of 1825-6, x, 399. ---- of January, 1835, xxviii, 177. ---- winter of 1837, 1838, in England, _J. Lindley_, xxix, 18. _Colden, Cadwallader_, correspondence with _Gronovius, Linnæus, &c._, xliv, 85. Collapse of a reservoir, _R. Hare_, xxxiii, 242.^f _Collins, Z._, herbarium of, xxiii, 398. _Collinson, P._, letters from, to _C. Colden_, xliv, 112. Colombia, features of, _R. Wright_, xxxvii, 2. ----, river Orinoco, rise of, xxxvii, 2. ----, climate and seasons of, xxxvii, 2. ----, mists above 12000 feet, xxxvii, 3. ----, llamas and horses of, xxxvii, 14. ----, vegetation and productions of, xxxvii, 15. Colophane, a tree affording an aromatic oil, ix, 386. Colophonite, of Willsboro', N. Y., _H. Seybert_, v, 117. Color of air and deep waters, and some other analogous fugitive colors, _Count Xavier de Maistre_, xxvi, 65.^f ---- of opaline glass, xxvi, 66. ---- of leaves in autumn, _Macaire Prinsep's_ views respecting, xvi, 215. ---- of the Raphael Tapestries, effect of light and air in restoring, xxxvii, 244. ---- of the sea, due in part to iodine and bromine, xvii, 170. ---- of wood of certain trees, change of, xviii, 404. ----, blue, from buck-wheat, xxii, 384. ----, carmine, produced on ivory by red lead on the under side, xxvi, 74. ----, increase of, when objects are seen with the head inverted, _D. Brewster_, xl, 343. ----, inability to distinguish, xl, 54. Coloring matter for dyeing, experiments on, _M. Persoz_, xxiv, 380. ---- ---- of the Lichen rocella, xviii, 151. ---- materials for confectioners, xxii, 381. Columbic acid, _A. A. Hayes_, xlvi, 166. Columbite, investigations on, _Rose_, xlix, 228. ---- from New Hampshire, large crystal of, _C. U. Shepard_, xvii, 357.^f ----, stanniferous, discovered in Massachusetts by _C. U. Shepard_, xvi, 220.^f ----, a large crystal of, from Middlelown, Conn., _J. Johnston_, xxx, 387.^f ----, localities of, in Connecticut, iv, 52; vi, 236; xxx, 387; xxxiii, 162. ----, in Mass., xvi, 220.^f ----, in New Hampshire, xvii, 357. ----, Torrelite of _Thomson_ identical with, _J. D. Dana_, xxxii, 149.^f