502 



PHYSICAL SCIENCES. 



LIQUIDS. 



Liquids, conditions affecting the trans- 

 mission of radiant heat by, 263 ; 

 evaporation from, 269 ; expansion 

 of, by heat, 271 ; propagation of 

 heat in, 273 ; action of heat as a 

 mechanical force on, 275-277. 



London, retarding of the tidal wave 

 between Aberdeen and, 94. 



, pendulum vibrating in its lati- 

 tude, a standard of measurement, 

 89 ; fulgorites exhibited in, 293. 



Long, Dr., his attempt to measure 

 distances of fixed stars, 388, 



Longitude, mode of reckoning mean 

 and true, 9 ; of the perihelion and 

 of the epoch defined, 10; cause of 

 periodical perturbations in, 14 ; 

 calculation from the moon's influ- 

 ence on the sun's, 55 ; data of, used 

 in computing a planet's place in 

 the heavens, 58-60 ; change effected 

 by precession and nutation in, 

 81. 



Lloyd, experiments of, in polarization 

 of heat, 264. 



Lubbock, Sir John, theory of plane- 

 tary motion completed by, 64 ; his 

 theory of shooting stars, 423. 



Lumiere cendre, definition of, 227. 



Lunar distance, defined, 43. 



theory, mean distances obtained 



from, 43. 



tides of the terrestrial atmos- 

 phere, 121. 



Lundahles, M., motions of heavenly 

 bodies investigated by, 405. 



Lupus, position of, 390. 



Lussac, Gay, M., uniting of gases by 

 volumes discovered by, 111 ; ascent 

 of, in a balloon, 118 ; course of 

 a lightning flash ascertained by, 

 292. 



Lutetia, diameter of, 56. 



Lyell, Sir Charles, his theory of 

 changes of temperature in the 

 northern hemisphere, 75 ; annual 

 number of volcanic eruptions com- 

 puted by, 233 ; volcanic pheno- 

 mena related by, 234. 



Lyncis 12, a triple star, 395. 



Lyra, a variable star in, 391 ; a 

 double star, 395 ; nebula, 410. 



MAGNETO. 



MACHINERY, relations of, to force, 

 353. 



Mackintosh, Sir James, quotation from, 

 illustrating the essential advantages 

 of study, 1. 



Maclear, Mr., parallax calculated by, 

 387. 



Madeira, vegetation of, 252. 



Madras, Saturn's ring discovered from, 

 66. 



Magnecrystallic action, 349 ; tem- 

 perature affecting, 352. 



Magnetic bodies, diffei'ence in power 

 of, 347. 



: elements, the three terrestrial, 

 343. 



equator of the earth, 343. 



meridian, the, mean action of 



forces determining, 343. 



poles of the earth, 343. 



storms, 344 ; varying with lati- 

 tude, 345, 346. 



Magnetism, source of, 318; producing 

 electrical phenomena, 322, 323 ; 

 rotatory "motion a source of, 330 ; 

 classification of substances, with 

 regard to their susceptibility of, 

 332 ; residing in substances after 

 two manners, 335 ; experiment il- 

 lustrating the forces of, 338 ; anti- 

 thesis, its general character, 339 ; 

 form of its lines of force, 339, 340 ; 

 analogous properties of electricity 

 and of, 340, 341 ; terrestrial, 342- 

 347 ; connexion between solar and 

 terrestrial, 344 ; action of, in 

 crystals, 349-351 ; influence of 

 temperature in, 352 ; affecting elas- 

 ticity of matter, 352, 353 ; a pro- 

 perty of the ethereal medium (?), 

 356, 357. 



, electro, discovery, importance of 



the science, 312 ; rotation effected 

 by, 313, 314; electric intensity 

 measured, 315; action of currents 

 in, defined, 316; Ampere's theory 

 of, 317, 318; causing rotation of 

 polarized rays, 319; action of, 

 on light, 320 ; accidental combina- 

 tions, 342 ; influencing metallifer- 

 ous deposits, 346. 



Magneto-electricity, principle suggest- 



