Prehnite, _L. P. Walmstedt_ on, ix, 378. ----, datholite, &c. at Kewenaw Point, Lake Superior, _C. T. Jackson_, xlix, 87. ----, in Connecticut, i, 50, 135; ii, 232; vi, 223. ----, in Massachusetts, i, 114; iii, 364. ----, in New Jersey, ii, 183, 191, 195, 197; v, 239; xl, 69; xliv, 58. ----, in Pennsylvania, x, 220. Premiums by the French Academy of Sciences, for 1827, xiv, 380, 389. ---- ---- ----, for 1831, xxii, 194. ---- offered by the Society for the Encouragement of National Industry, France, 1821, 1822, iv, 192. ---- ---- ----, for 1832-34, xxii, 359. ----, for Mechanical Arts, iv, 192. ----, for Chemical Arts, iv, 192. ----, for fabrication of Russian leather, iv, 193. ----, for Economical Arts, iv, 193. ----, for useful inventions in agriculture, xviii, 382. ----, for chemical and medical discoveries, xxii, 194. ----, scientific, xxiv, 210. ----, see farther under _Medals_ and _Prizes_. Prenanthes aphylla, v, 299. Preservation of objects in Natural History, iv, 198. ---- of specimens of animals, directions for, xii, 271; xix, 52. ---- ---- ibid, with arsenical soap, xix, 53. ---- of zoological collections from insects, _T. S. Trail_, xv, 167. ---- of animal and vegetable substances from insects, _J. Macartney_, xxxi, 367. ---- of specimens, new mode of, _J. L. Riddell_, xxxv, 338. ---- of eggs, Scotch method, xxvi, 188. ---- ---- for cabinets, xxi, 161. ---- of insects, _T. Roger_, xix, 213. ---- ----, xix, 56; xxi, 162. ----, of freshwater shells, xlii, 391. ---- of Echini with the spines, xxix, 353. ---- of skins, xxvi, 188. ---- of fish skins for museums, xxxvi, 196. ---- of anatomical preparations, vi, 384. ---- of skeletons, xix, 57. ---- of animal bodies, new mode of, by petrifaction, _G. Segato_, xxix, 359. ---- of animal preparations, by Gannal's new process, xl, 194. ---- of animal substances, salt for, xxx, 183. ---- of crystalline lenses, xxvi, 216. ---- of dead bodies, i, 307. ---- of meats, &c. by Appert's process, xiii, 163. ---- of fruits without sugar, method of, xv, 381. ---- of substances by alkalies, xxiii, 383. ---- of cordage, &c. from moisture, xxiii, 199. ---- of firemen against fire and flame, xviii, 177; xx, 96.^f ---- of grain from mice, vii, 378. ---- of timber by pyrolignite of iron, _Boucherie_, xl, 213. ---- of the Royal George, xl, 213. ---- from rust, a mode of, by means of caoutchouc, vi, 398. ---- of iron from rust, xix, 203; xxi, 150; xxii, 382; xxiii, 199, 383. _Presl_, notice of the Genera Fileacearum of, xxxix, 174. Press, botanical, _J. Locke_, xxx, 54.^f ----, printing, see _Printing_. Pressure in the ocean at great depths, see _Ocean_. ----, atmospheric, see _Barometrical_. ---- on the human body, variations of, and apparatus for withdrawing, xxxiv, 30. ----, effect of instantaneous, as compared with accumulative, _C. Bonnycastle_, xl, 32.