482 



PHYSICAL SCIEXCES. 



AURORA. 



static and in voltaic electricity, 317 ; 

 action of planetary, on comet's or- 

 bits, 361-363; range of solar, 

 365. 



Aurora, the, affecting the compass, 

 312. 



Australia, evidence of deserts in the 

 interior of, 124; species of plants 

 common to Europe and, 251. 



Auvergne, temperature of hot springs 

 in, 231. 



Axes, change in form of masses re- 

 volving round, 6. 



, major, length of, in orbits, in- 

 variable, 20 ; of the orbits of Ju- 

 piter's satellites, cause of the direct 

 motion observed in, 28 ; position 

 of, in the solar system, 65 ; a 

 nutation in planetary, 66 ; of the 

 moon, 68, 69; mechanical law 

 affecting, 76. 



, optic, of crystals, 183. 



Axis, greater, of the earth's orbit, 

 period of its revolution, 38 ; period 

 of the earth's revolution, 58 ; excess 

 of Jupiter's equatorial over his 

 polar, 66 ; of rotation, proof of its 

 being invariable, 76, 77. 



, major, of a planet's orbit, dis- 

 tance from the sun measured by, 8 ; 

 designation of its extremities, 9 ; 

 length of, determining the form of 

 the orbit, 10 ; periods of its revolu- 

 tions, 17 ; length of, not perma- 

 nently changed, 20 ; Jupiter's pe- 

 riodically diminished, Saturn's in- 

 creased, 26 ; of the solar ellipse, 

 period of its revolution, 86. 



, magnecrystallic, 349. 



Azores, the, icebergs reaching, 100. 



BABBAGE, Charles, his theory of vol- 

 canic action, 235-237 ; quotation 

 from, on the nature of force, 

 353. 



Babinet, M., his theory of dark lines 

 observed in the solar spectrum, 

 163 ; comet's light computed by, 

 359. 



Babylon, eclipse observed at, 36. 



Bacon, Francis, anticipation of dis- 

 covery by, 32. 



BECQUEREL. 



Baily, Mr., compression of the terres- 

 trial spheroid calculated by, 50 ; 

 density of the earth determined, 

 57 ; fictitious antiquity ascribed to 

 Indian astronomical observations, 

 88. 



Bali, volcanic eruption in, 233. 



Balloon, rarity of the air felt in a, 

 118; observations made from, 

 119. 



Baltic, the, a tideless sea, 98 ; de- 

 creased atmospheric pressure on 

 the shores of, 120. 



Barlow, Mr., observations supporting 

 his theory of electric currents, 346. 



Barometer, the, principles of cohesion 

 and attraction applied to the con- 

 struction of, 113; density of the 

 atmosphere measured by, 117 ; 

 mean heights of, varying with at- 

 mospheric densities, 118 ; mountain 

 heights measured by, 119, 120; 

 atmospheric phenomena affecting, 

 120 ; used to trace the course of 

 atmospheric waves, 121 ; cause of 

 sudden fall in, before hurricanes, 

 127 ; refraction varying with, 154. 



Barrow, Cape, observations on mag- 

 netic storms at, 345, 346. 



Battery, voltaic, construction of, 298, 

 299 ; Professor Daniell's improve- 

 ments, 299, 300 ; action of, charged 

 with water, 300; constant flo\v 

 of electricity obtained by means of, 

 312. 



, magnetic, constructed by Dr. 



Faraday, 324, 325 ; Mr. Henley's 

 magneto-electric, 325; Atlantic tele- 

 graph, 326 ; structure of, for land 

 telegraphs, 328; relation of heat 

 to power of, 329 ; thermo-electric, 

 333. 



Batsha, port of, tides neutralised in, 

 99. 



Bayle, comparative density of the at- 

 mosphere in interplanetary space 

 according to his law, 356. 



Bear, Little, the, the polar star in 

 82. 



Becquerel, M. E., unexplained pho- 

 tographic phenomenon observed 

 by, 213; phosphorescent property 



