TY S 270 URA 
Twilight bow, account of, S. F. B. 
Morse, xxxviii, 389. U. 
Twin crystals, formation of, J. D. 
Dana, xxx, 275.f 
of Columbite, 
Shepard, xvii, 358.f 
Twine, see Cordage. 
Twining, A. C., method of resolving 
equations of the third and fourth 
degrees, ix, 86. 
, observations on meteors, xi, 
184, 
, on the growth of timber, 
xxiv, 391. 
, on the position and height of 
some Auroral arches and stream- 
ers, xxxil, 217. 
, on the Aurora of September, 
1839, xxxviii, 376. 
, supernumerary 
5-0-0. 1. PAT 
, halos in January, 1835, xxxii, 
229. 
, on the appearance, nature 
and cause of the meteors of No- 
vember 13, 1833, in reply to D. 
Olmsted, xxvi, 320.f 
—, ibid, Nov. 1834, xxvii, 339. 
, suggestions on the solar 
eclipse of July, 1842, xlii, 395. 
, on the parallelogram of for- 
ces, xlvi, 324.f 
Twinkling of fixed stars, v, 156. 
, remarks on, B. 
Hallowell, xv, 360. 
Tyfoons of the China Sea, xxxv, 
209; xxxvi, 59. 
Cons 
rainbows, 
—— at Balasore, xxxv, 220. 
at Canton, xxxv, 217, 218. 
at Manilla, xxxv, 220. 
, Raleigh’s, xxxv, 210; 
59. 
, method of escaping, xxxv,216. 
, see farther under Winds. 
Tyler, J. W., solar halo, seen at 
Cazenovia, N. Y., xxi, 189. 
Tyrannula, see under Zoology. 
Tyrian dye, xxxvili, 126. 
Tyson, P. T., on the minerals of, 
Baltimore and Harford Cos., Ma- 
ryland, xviii, 78. 
XXXVIl, 
Ulcers cured by chloride of lime, 
xii, 179. 
Ultramarine, artificial, xv, 392; 
xxl, 368 5 xxiv, 373; xxvii, 195; 
xxvill, 144. 
Unger, on xanthic oxide in guano, 
xlix, 200, 391. 
Unicorn, on the existence of, J. F. 
Laterrade, xxi, 123: 
Unio, see under Zootoey, Mollusca. 
Unionide of the country of the 
Iguanodon, G. A. Mantell, xlvii, 
402.f 
Unit, linear, proposed by Davy, 
xvii, 164. 
United States, earliest census of, 
Xxxill, 278. 
, magnetic chart of, E. Loo- 
mis, xxxiv, 290; xxxix, 41. 
, plan for the survey of the 
coast, xvi, 225. 
~, architecture in, xvii, 99, 249f 
XV, 11212: 
, culture of silk in, xvin, 278. 
, statistics of iron in, xxii, 179. 
, Medical and Surgical Jour- 
nal, noticed, xxvii, 180. 
, Naval Lyceum, xxvii, 390. 
, distribution of plants in, S. 
Forry, x\vii, 221. 
; amelioration of climate in, 
D. Thomas, xix, 361. 
, climate of, S. Forry, xlvii, 
18f, 221. 
Universal terms, Emma Willard, 
xxill, 18. 
Universe, on the formation of, I. 
Orr, vi, 128.f 
University of the State of New 
York, Report of the Regents of, 
xxil, 415; xxv, 258; xxvii, 177; 
xxx, 389; xlix, 176. 
, see Education. 
Upas, analysis of the juice of, 
xxxix, 206. 
Upham, C. W., memoirs of J. 
Prince, xxxi, 201.f 
Ural, mines of, see under Russza. 
