Hygrometry, a method of experimenting in, x, 387. Hyperbola, method of describing, _R. G. Hazard_, xxi, 314.^f Hypersthene of N. York, analysis of, _L. C. Beck_, xlvi, 35. ----, in Massachusetts, iv, 55. Hyssopus anisatus, iv, 65. I. Ice, artificial preparation of, xviii, 145. ----, evaporation of, xvi, 390. ----, formation of, in still water, iii, 179. ----, ----, at the bottom of rivers, _H. W. Sheffey_, xxxvi, 186. ----, ----, ibid, _T. Stratton_, xl, 407. ----, ----, sparks given out during, xxvi, 178. ---- in a well, xxxvi, 184. ---- of the sea, characters of, and remarks on, v, 131. ----, Greenland, i, 101. ---- of the Alps, _J. D. Forbes_, xlvi, 173; --veined structure and motion consequence of its viscous condition, xlvi, 174, 175. Icebergs, remarks on, v, 131. ----, formation of, _C. Wilkes_, xlvii, 114. ----, _J. P. Couthouy_, xliii, 154. ----, character of, and facts concerning, _J. L. Hayes_, xlv, 316. ---- and currents of the North Atlantic, _W. C. Redfield_, xlviii, 373.^f ---- in low latitudes, xxii, 200. ----, theory of drift, see _Drift_. Ice houses, natural, iv, 174. ---- ----, ----, in Salisbury, Ct., viii, 254. ---- ----, ----, near Williamstown, Mass., iv, 331; v, 398. ---- ----, ----, of St. Ouen, xii, 184. Ice mountain of Hampshire Co., Va., _C. B. Hayden_, xlv, 78.^f ---- ---- in Vermont, _S. P. Lathrop_, xlvi, 331. ---- water, drinking of, xv, 194. Iceland, notice of, xvii, 15. ----, geysers, springs, &c. of, _E. Robert_, xxxi, 167; xxxii, 196. ----, ----, remarks on, _G. Bischof_, xxxvi, 255. Ichnolithology, see _Footprints_. Ichthyolites, see _Fish_. Ichthyosaurus, largest, found by _Mary Anning_, xxviii, 369. ----, in U. States, xxvii, 353. ---- at Strensham, England, xxxviii, 126. Ichthyosauri, _T. Hawkins_, xxvii, 413. Iconography, xxxiii, 184. _Ideler, J. L._, views of, on meteorites, shooting stars and Auroras, xxviii, 288. Idocrase, analysis of, _T. Richardson_, xxxviii, 120. ----, of Skye, xxviii, 395. ----, American, first detected, _W. Meade_, vii, 50. ----, crystal, from Amherst, N. H., xlvi, 381.^f ----, in Connecticut, ix, 44. ----, in Massachusetts, viii, 44; x, 11. ----, in N. York, xvii, 145; xxi, 327; xlvi, 35. ----, in Rhode Island, viii, 230. Idria quicksilver mines, xxix, 219. Igneous action, as indicated by certain minerals in New York, _L. C. Beck_, xlvi, 333. ---- origin of some trap rocks, _B. Silliman_, xvii, 119. ---- ---- ibid, _T. Cooper_, iv, 205. ---- theory of the earth, remarks on, _W. Maclure_, xvi, 351. ---- ---- ----, as connected with the secular variation of the magnetic needle, _J. H. Lathrop_, xxxviii, 68. ---- ---- ----, applications of, ibid, xxxix, 90. Ignis fatuus, observations on, _J. Mitchell_, xvi, 246. Iguanodon, bones of, in Mantell's Museum, xxiii, 165. ----, discovery of, xxvii, 355.^f ----, Maidstone, xxvii, 420. Ilicine, in fevers, xxii, 349.