Pye? oO. PY ees; 
COMPRISING 
MECHANICS, ACOUSTICS, PYRONOMICS, OPTICS, MAGNETISM AND 
ELECTRICITY, AND METEOROLOGY. 
[The numbers refer to the top paging of the text.] 
Acuromatic Lenses, -124. 
Achromatism, nature of, 123; in the eye, 125. 
Acoustics, 69. 
Aeriform bodies, statics of, 49 ; velocity of efflux 
of, 46, 67. 
Aerodynamics. See Pneumatics. 
Aerolites, shape and structure of, 240. 
Aerostatics, 5, 49. 
Air, weight, elasticity, pressure, &c., of, 49; on 
the motion of the, 65; laws relating to the 
escape of, 67; transmission of sound through 
the, 72; air waves, 75; mixture of vapor 
with, 95; currents, 198; not perfectly trans- 
parent, 225. 
Air-balloon, 62; Montgolfier’s, ib. ; 
ton, 63. 
Air-pump, the, 55 ; cock and valve, one and two 
cylindered, 56 ; ‘application of, 57. 
America, elimats. of, 190. 
Ammonia, present in the atniogphiers: 185. 
Ampére’s apparatus for determining the influence 
of terrestrial magnetism, 172 ; his explanation 
of certain phenomena exhibited by galvanic 
currents, 174; explains the rotation of a mag- 
net round its own axis, 176. 
Anemomieters, description of various, 197. 
Animal heat, 109. 
Arago, his experiments in rotation magnetism, 
181 ; his classification of the varieties of light- 
ning, 243. 
Arago and Dulong’s experiments for verifying 
Mariotte’s law respecting gaseous volumes, 
52; apparatus for determining the elasticity 
of vapor at very high pressures, 92. 
Archimedes’ remark on the power of the lever, 
calculation illustrative of, 11 ; law of, respect- 
ing fluids, 39 ; his law respecting liquid bodies 
also applicable to gaseous, 62. 
Areometers, Nicholson’s and Gay Lussac’s, 42. 
Armature, the, 146. 
Athermanous bodies, 106. 
Atmosphere, chemical constituents of the, 184; 
higher layers of, colder than the lower, 191; 
method of measuring the pressure of the, 193 ; 
moisture of the, 206; optical phenomena of 
the, 225; variations in the blue tint of, 226 ; 
the morning and evening red of the, ib.; 
various phenomena of the, arising from refrac- 
tion and reflection, 228 ; the fiery phenomena 
of the, 237 ; electric phenomena of the, 242. 
Attraction between solid and liquid bodies, 43. 
Atwood’s machine for demonstrating the laws 
of freely falling bodies, 28. 
the Hamp- 
August’s psychrometer, 208. 
Aurora borealis, the, magnetic in its character, 
253 ; description of, 254; rate of its occurrence 
in early times, ib. ; sometimes visible in the tor- 
rid zone and southern hemisphere, 255 ; various 
theories of the, 256. 
Axis of flexion, the, 18. 
Babinet’s improvement in the air-pump, 56. 
Balance, the, 9. 
Barometer, the, of Torricelli, 50; cistern and 
syphon, ib. ; Fortin’s, 51; Kopp’s differential, 
53; diurnal and annual variations of the, 193 ; 
table of mean height of, for different places, 
195 ; its use in predicting changes of weather, 
ib. ; table of the influence of various winds 
on, 201. 
Battery, Volta’s galvanic, 157 ; Becquerel’s con- 
stant, 158; Daniel’s, Grove’s, and Bunsen’s, 
159; difference between a compound and a 
simple, 164. 
Becquerel’s constant battery, 158 ; and Fechner’s 
improvements of the dry pile, 161. 
Bellows, the common and other, 66. 
Bennett’s gold leaf electrometer, 147. 
Blower, the cylindrical, 66. 
Bodies, properties of, 1 ; division of, into simple 
and compound, 2; solid, liquid, aeriform or 
gaseous, 3; inertia of, ib. ; the statics of solid, 
5; strength of, considered, 17 ; dynamics of 
solid, 25; theory of freely falling, 28 ; liquid, 
37; specific gravity of, 39 ; attraction between 
liquid and solid, 43 ; statics of aeriform, 49 ; 
effects of heat in changing the state of aggre- 
gation of, 90 ; specific heat of, 102; diather- 
manous and athermanous, 106 ; conduction of 
heat from one body to another, 108 ; luminous 
and non-luminous, 109 ; magnetic, indifferent, 
and diamagnetic, 141 ; electrical properties of 
different, 146 ; motions of electrified, 154. 
Bohnenberger’s application of the dry pile to the 
gold leaf electrometer, 161. 
Boiling of liquids, rationale of, 96. 
Bouguer’s investigations with the plummet on 
Chimborazo, 35. 
Bramah’s hydraulic press, 61. 
Breezes, land and sea, 198. 
Breguet’s thermometer, 88. 
Brewster’s kaleidoscope, description of, 112 ; for- 
mula for obtaining the angle of polarization, 137. 
Brix’s apparatus for measuring latent heat, 98. 
Brocken, spectre of the, 234. 
Bunsen’s carbon battery, 159. 
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