453 



Jupiter, magnitude of, 56. 



, mass of, 55. 



, rotation of, 61. 



, precession and nutation of, 28. 



, in conjunction and opposition, 



30. Note 96. 

 and Saturn, their theory, 24. 



Note 84. 

 Jupiter's satellites, theory of, 26. 



, masses of, 26, 54. 



, orbits* of, 26, 27. Notes 86, 87. 



, law in the mean motions and 



mean longitudes of, 28. 

 , svnodic motions of, 29. Note 



92. 



, eclipses of, 29. Notes 93, 94. 



, configuration of, 27. Note 88. 



, effect of Jupiter's form on, 26. 



, secular variations of, 27 et seg. 



, periodic variations of, 28. 



, effects of the displacement of 



Jupiter's equator and orbit on, 28. 



Note 90. 



, rotation of, 65. 



, libration of, 64. 



Kaler. Capt., determines the length 

 of the seconds pendulum at Lon- 

 don, 84. 



Kempelen and Kratzenstein, their 

 speaking machine, 147. 



Kepler discovers the form of the 

 planetary orbits, 5. Note 26. His 

 laws, ib. 



Kupffer, M., his observations on the 

 isothermal lines, and the poles of 

 maximum cold, 261. Discovers 

 a nocturnal variation in the com- 

 lss, 303. 



La Grange, M., proves the stability 



of the Solar System, 22. 

 Lalande, M., his computation of the 



contemporaneous conjunctions of 



the planets, 41. 

 Laminae, vibrations of, 140. Notes 



181, lr-J. 

 Lamouroui, M., on the distribution 



of sea-weeds, 267. 

 Languages, collation of, 270. 

 , vocal articulation of, imitated 



by machines, 147. 



La Place, the Marquis, his determi- 

 nation of the invariable plane, 22 ; 



and of the great inequality of Ju 



piter and Saturn, 24. Proves that 

 the lunar perigee and nodes are 

 not affected by the resistance 

 of ether, 36. He discovers the 

 cause of the lunar acceleration, 

 ib. His theory of spheroids, 43. 

 He ascribes the motions of the 

 planets to a common original 

 cause, 61 . Proposes the year 1250 

 as a universal epoch, 81. Quota- 

 tion from, 82. Proves the Indian 

 tables to be as recent as Ptolemy, 

 83. Proves that the discrepancy 

 between Newton's theory of the 

 tides, and observation, depends 

 upon the depth of the sea, 86. On 

 the utility of investigations of 

 cause and effect, 90. On capilla- 

 ry attraction, 109. On the oscil- 

 lations of the atmosphere, 115. 

 On the comet of 1770, 338. On 

 Halley's comet, 342. On the ex- 

 tent of solar attraction, 344. On 

 the comet of 1682, 357. On the 

 origin of the Solar System, 377. 



Latent heat, 226. 



Latitude, terrestrial, 4. Note 11. 



, celestial, 9. Note 54. 



, square of the sine of the, 47. 



Note 126. 



Length of a wave, 124. 



of the seasons variable, 69. 



of the day invariable, 66. 



of the civil year, 79. 



of the Egyptian year, 80. 



of a degree of the meridian, 



46. 



of the pendulum at London, 



84. 



of the tails of comets, 355. 



Lens, 159. The glasses of a tele- 

 scope and of spectacles are lenses. 



Leslie, Sir John, his theory of the 

 internal structure of the globe, 73. 

 On radiant heat, 207. 



Level of the sea, 84. Note 150. 



Lexel, M., his comet, 340. 



Libration of the moon, 64. 



of Jupiter's satellites, 64. 



Light, 148. 



, velocity of, 31. 



, reflection and refraction of, 



148, 170. Notes 184, 198. 



, analysis of, 154. Note 190. 



, absorption of, 154. 



, intensity of, 164. 



, dispersion and deviation of, 



158, 191. 



, propagation of, 164, 171. 



