INDEX. 



518 



Force, electric, 313. 



of lightning, 322. 



Forces which fix the nature of the conic 

 sections in which the planets and 

 comets move, 411. Note 222. 



Forster, Lieut., remarks on the clear- 

 ness with which sound is transmitted 

 over ice, 152. 



Foster, Capt., barometric depressions j 

 observed by, 134. 



Fourier, M., his estimate of the tempe- 

 rature of space, 276. On the decrease 

 of central heat, 281. 



Fox, Mr., on the temperature of mines, 

 2/7. On the law of magnetic inten- 

 sity, 351. On currents of electricity 

 in metallic veins, 379. 



Franklin, Sir John, his observations on 

 the temperature of the Arctic regions, 

 297. 



Fraunhofer, Professor, his dark lines in 

 the solar spectrum, 182. His solar 

 spectrum, 223. 



Fresnel, M., proves the extraordinary 

 ray to be wanting in some substances, 

 205. His experiments on circular 

 and elliptical polarization, 215; and 

 on light passing through the axis of 

 quartz, 216. On the interference of 

 light, 217- 



Fringes of colour about circular aper- 

 tures, 194. Note 196. 



Fulgorites, 322. 



Fundamental note in music, 157. 



G. 



Galileo first observed the nodal points 

 of vibrating bodies, 162. 



Galvani, Professor, his discovery, 330. 



Galvanometer, 360. 



Gambart, M., his computation of the 

 elements of a comet, 396. 



Gardner, Mr., on the configuration of 

 land and water, 295. 



Gases diamagnetic, 370. 



Gay-Lussac, M., his law of the combi- 

 nation of gases, 121. His estimation 

 of the length of a flash of lightning, 

 ,'521. 



Gensanne, M., his observations on the 



heat of mines, 277- 

 Giesecke, Sir Charles, on isothermal 



lines, 297. 

 Glass, impermeable to heat, 242 et seq. 



prism, 178. Note 190. 



, crown and flint, properties of, 



183. 

 , polarising angle of, 207. Note 



205. 



, vibrations of, 164. 



Goodricke, M., his opinion of variable 



stars, 425. 

 Graham, his compensation pendulum, 



257. 



Gravitation, 4, 51. Note 5. 

 , terrestrial, 5. 



decreases from the poles to the 



equator, 51. 



, the intensity of, 5. Note 13. 



of the planets and satellites, 6. 



Note 28. 



, universal, 7 et seq. 



, the nature of, 452. 



proportional to the mass, 7. Notes 



27,28. 

 , a consequence of electric action, 



115 et seq. 



Gravity, the direction of, 50. 

 Great inequality of Jupiter and Saturn, 



29, 99. 



Great comet of 1843, 401. 

 Grimaldi, his discovery of coloured 



fringes on the borders of shadows, 



195. 

 Grylli, grasshoppers, crickets, locusts, 



&c., 146. 

 Gymnotus electricus, 340. 



H. 



Haidinger, M., his experiments on crys- 

 tallization, 124. 



Hall, the first to construct an achro- 

 matic telescope, 184. 



Halley's comet, 390. 



Hansteen, Professor, discovers all sub- 

 stances to be magnetic in a certain 

 position, 348. 



Harmonic divisions of a musical string, 

 156. 



L L 



