Iolite, analyses of, xlvi, 383. ----, in Connecticut, xxii, 389. ----, in Massachusetts, xxxiii, 399. ----, decomposed varieties of, _C. U. Shepard_, xli, 354. Iowa, mounds of various imitative shapes in, _S. Taylor_, xliv, 21.^f Ipecacuana, analysis of, xvii, 385. Ireland, geographical distribution of plants in, xxxi, 367. Iridium, method of obtaining, from the platinum residue, _F. Wöhler_, xxvi, 371. ----, means of obtaining pure, _Fremy_, xlviii, 185. Iris, affords a good test liquor, v, 408. Iris Duerinckii, xlv, 176. ---- lacustris, iv, 57. Iriscope, _Reade's_ experiments with, xl, 334. Iron, action of, on ammonia, xviii, 146. ----, action of air and water on, _Mallet_, xliv, 355. ----, steel and cast iron, remarks on, xxxviii, 121. ----, method of bronzing, xxx, 173. ----, ---- of browning, ix, 168. ----, cementation of, by carburetted hydrogen, xxviii, 362. ----, cold short, method of purifying, xxx, 173. ----, chlorine in, _C. U. Shepard_, xliii, 359. ----, corrosion of, by salt water, xxxiii, 286. ---- when cutting, action of, in motion, on tempered steel, ix, 324; x, 127; xi, 384. ----, deoxidation of the salts of the peroxide of, _C. F. Schönbein_, xlix, 203. ----, experiments on two varieties made from the magnetic ores of Essex Co., N. Y., _W. R. Johnson_, xxxvi, 94.^f ----, manufacture of, by use of anthracite, xxxiii, 266. ----, ----, with the hot blast, xxix, 356. ----, ----, with the hot blast, _T. Clark_, xxxi, 180. ----, ----, by the hot and cold blast, comparative strength of, _Fairburn_, xxxiii, 292. ----, ----, ibid, comparative composition of, _T. Thomson_, xxxiv, 21. ----, ----, gas obtained by water applied in, _J. S. Dawes_, xxxv, 303. ----, oxides of, separation of, _J. Liebig_, xxiii, 379. ----, ----, effect of, on soil, xli, 159. ---- for railways, _D. Mushet_, xxxiv, 15. ----, separation of, from manganese, xiii, 173. ----, method of silvering, xxx, 169. ----, on the different states of, xiii, 159. ----, state of, in soils, _R. Phillips, Jr._, xlix, 394. ----, use of, for stereotyping, xxvi, 192. ----, sulphur in bar, xxviii, 71. ----, sulphuret of, formation of, xxxi, 74. ---- boat, iii, 371. ---- bridge in Prussia, xii, 197. ---- cement, xxx, 171. ---- conduit pipes, vi, 173. ---- furnaces, number in England and Scotland, xvi, 395. ---- mountain of Missouri, iii, 63. ---- ---- ibid, _J. T. Hodge_, xliii, 58. ---- spikes, experiments on the adhesion of, _W. R. Johnson_, xxxii, 34.^f ---- trade of Great Britain, amount of, xx, 176. ---- ---- of Wales, xx, 182. ---- works of Sweden, amount of exports from, in 1828, xviii, 173. ---- ---- of Glasgow, xli, 48. ---- ---- of Russia, improvements in, xxx, 181. ---- ---- of McIntyre, Essex Co., N. Y., _W. C. Redfield_, xxxiii, 303. ---- ----, statistics of, in the U. States, xxii, 179. ---- ----, ----, in Connecticut, _C. U. Shepard_, xxxiii, 157.