Balloon with rarefied air, xii, 372. ----, effect of solar heat in raising, _J. Rae_, xxxiii, 196. ----, principles of aerial navigation, _H. Strait_, xxv, 15.^f ----, a means of making meteorological observations, xlii, 150. ----, observations during an ascent of, by _Eugene Robertson_, xii, 166, 325. _Banks, J._, herbarium of, xl, 9. Bare Hills, Maryland, _H. H. Hayden_, xxiv, 349.^f Barium, extrication of, _R. Hare_, xxxvii, 267; xxxviii, 115; xxxix, 362. ----, method of preparing the deutoxide of, xvi, 395. Bark, Peruvian, experiments on, by _G. W. Carpenter_, ix, 363. Barlow, P., instruments for illustrating the effects of electro-magnetism, v, 396.^f _Barnard, F. A. P._, aurora borealis of Nov. 14, 1837, xxxiv, 267. ----, improvement in the Daguerrotype process, xli, 352. _Barnes, D. H._, geological section of the Canaan Mt., N. Y., v, 8. ----, on some doubtful reptiles of North America, xiii, 66. ----, notice respecting magnetic polarity, xiii, 70. ----, ----, reply to, xiv, 121. ----, on the genera Unio and Alasmodonta, vi, 167,^f 258.^f ----, new species of Chiton, vii, 69.^f Barometer, construction of, in America, _J. Green_, xxvii, 292. ----, new construction of, _J. L. Riddell_, xxvii, 223.^f ----, improvement of, _C. F. Durant_, xxvii, 97.^f ----, new form of, _J. H. Alexander_, xlv, 233.^f ----, new self-registering, xlix, 400. ----, effect of sound on, xxx, 377. ----, directions regarding, by _E. Mitchell_, xx, 364.^f ----, siphon, in determining the temperature of the mercury in, by observation, xl, 250.^f ----, water, constructed in London, xxiv, 198. ----, remarks on, _W. C. Redfield_, xxv, 129. ----, use of, at sea, _W. C. Redfield_, xxv, 198. ----, changes in the column, as connected with the progress of a storm, _W. C. Redfield_, xx, 45; xxv, 117; xxxi, 127; xxxiii, 262. ----, variations of, _W. C. Redfield_, xxxiii, 262. ----, ----, semi-diurnal, xxxiii, 263. ----, ----, from accumulation of atmospheric pressure owing to obstacles in the course of winds, xxxiii, 264. ----, oscillation of an extensive region in the higher or temperate latitudes, xxxiii, 264. ----, changes during a storm, _E. Loomis_, xl, 34. ----, ----, ibid, _J. P. Espy_, xxxix, 123. ----, ----, ibid, _M. Dové_, xliv, 315. ----, ----, remarks on, _W. S. W. Ruschenberger_, xxxiii, 345. ----, cause of the daily fluctuations of, _Espy_, xli, 42. ----, at the equator indicating time by its oscillations, ix, 195. ----, a substitute for, in measuring heights, _J. Robison_, xxxv, 294. ----, tube, filled with mercury without using an air pump, _Stevelly_, xxxviii, 109. ----, _Hudson's_ series of investigations with, xxiv, 393.