_Œrsted, H. C._, on water-spouts xxxvii, 250.^f ----, on tornadoes, xxxviii, 82. ----, allusion to discoveries electro-magnetism, v, 388. Oerstedite, xxx, 179. _Ogden, H. W._, on water-spouts, xxix, 254. Ohio, notes on, i, 207, 311. ----, Medical College of, i, 311. ----, Belmont Co., scenery, geology, mineralogy, botany, &c., of, _C. Atwater_, i, 226. ----, winds of, _C. Atwater_, i, 276. ----, vegetable impressions in the coal strata of Zanesville, _E. Granger_, iii, 5.^f ----, facts relating to certain parts of, _S. P. Hildreth_, x, 1; --Washington Co., soil, &c., 2; caverns on the Little Hockhocking, 3; limestone and coal, salt borings, 4; gas from springs, 5; petroleum, 5; iron ore, 7; ochres, pyrites, 8. ----, notes on, in reply to inquiries by C. Atwater, _S. P. Hildreth_, x, 152; --Marietta, size, manufactures, &c., 152; county of Washington, statistics, 153; settlement of different places of Ohio, 153, 154, 155; attacks of Indians, 154; escape of R. J. Meigs, 157; Indian Mounds, &c., 160. ----, ibid, _S. P. Hildreth_, xi, 231; --on the plants of, climate, &c., 231; epidemic disorders, influenza, &c., 233; diseases of cattle, 234; crimes, suicide, 235; education, 235; population of Marietta, 236; sect of Halcyons, 236; antiquities, 237; meteors, 237; storm of May 28, 1809, 238. ----, on the geology, climate, diseases, &c., of, _C. Atwater_, xi, 224. ----, Washington Co., climate and productions of, _S. P. Hildreth_, xii, 206. ----, coal and diluvial strata of, _S. P. Hildreth_, xiii, 38. ----, people of, _C. Atwater_, xiii, 200. ----, miscellaneous notices of rocks and minerals of, _S. P. Hildreth_, xvi, 154. ----, canals, xx, 416. ----, boulders of, _D._ and _I. A. Lapham_, xxii, 300. ----, saliferous rock formation of, _S. P. Hildreth_, xxiv, 46. ----, ten days in, xxv, 217; --Marietta, notice of, 217; Waterford, 221; Morgan Co., 227; Zanesville, 228; Putnam, 230; Muskingum Co., 230; Perry Co., 232; Flint ridge, 233; buhrstone, 233; Tumuli, 234; Somerset, 236; Rushville and Rush Creek, 236; Lancaster, 237; Pickaway Co., 238; Circleville ancient works, 238; Scioto aqueduct, 240; Williamsport, 247; the Barrens, 248; Westport, 249; Chilicothe, 251; Pickaway plains, 255. ----, channels of streams far below the general level, deeply seated, xxv, 223. ----, on the bituminous coal deposits of the Ohio valley, _S. P. Hildreth_, xxix, 1^f; --general topography, 7; Muskingum valley, 9^f; Putnam Hill strata, 30^f; cannel coal, 39; calcareous breccia, 43; Hockhocking valley, 46; buhrstone, 142. ----, miscellaneous notices of, _S. P. Hildreth_, xxxi, 1; --steamboats, 1; Sun-fish creek, 2; grave creek, bituminous coal, Wheeling and Indian attacks, 3; Wellsburg, Steubenville, 6; Judge Tappan's cabinet, 7;