450 



INDEX. 



position, 297. His experiments 

 on the transmission of electricity, 

 299. He produces rotatory motion 

 by the electric force, 315. His 

 experiments on magneto-electri- 

 city, 322. He proves the identity 

 of the electric and magnetic fluids, 

 324. His explanation of electrici- 

 ty evolved by rotation, 325. His 

 classification of magnetic sub- 

 stances, 327. His experiments on 

 the induction of terrestrial mag- 

 netism, 332. He supposes rota- 

 tion a cause of electric currents 

 in the earth, 333. On the evolu- 

 tion of electric currents, and iden- 

 tity of the different kinds of elec- 

 tricity, 336. 



Faye's comet, 341. 



Fiedler, Dr., his fulgorites, 283. 



Figure of the earth. See Earth. 



Fluids, the undulations of, 93. Note 

 156. 



, compression of, 99. 



, capillary attraction of, 111. 



Focal distance, 5. Note 22. 



length of a lens. Note 196. 



Foei of an ellipse, 5. Note 22, 



Forbes, Professor, his experiments 

 on heat, polarization of, 216. On 

 the heat of moonlight, 239. His 

 experiments during the annular 

 eclipse of the sun, 158. 



Force, the unknown cause of mo- 

 tion, 4 ct passim. 



proportional to velocity, 8. Note 



, gravitating, 6. See Gravita- 

 tion. 



, centrifugal, 5, 43. Notes 18, 



117. 



, molecular, 96. 



, electric, 274. 



of lightning, 282. 



Forces which fix the nature of the 

 conic sections in which the plan- 

 ets and cornets move; 360. Note 

 222. 



Foster, Capt., remarks on the clear- 

 ness with which sound is trans- 

 mitted over ice, 130. 



Fourier, M., his estimate of the tem- 

 perature of space, 240. On the 

 decrease of central heat, 245. 



Fox, Mr., on the temperature of 

 mines, 242. On the law of mag- 

 netic intensity, 308. On currents 

 of electricity in metallic veins, 331. 



Franklin, Sir John, his observations 



on the temperature of the Arctic 

 regions', 260. 



Fraunhofer, Professor, his dark lines 

 in the solar spectrum, 157. His 

 solar spectrum, 193. 



Fresnel, M., proves the extfaordina 

 ry ray to be wanting in some sub- 

 stances, 177. His experiments on 

 circular and elliptical polari/a 

 tion, 186; and on light passing 

 through the axis of quartz, 187. 

 On the interference of light, 188. 



Fringes of color about circular aper 

 tures, 168. Note 196. 



Fulgorites, 283. 



Fundamental note in music, 335. 



G. 



Galileo first observed the nodal 

 points of vibrating bodies, 140. 



Galvani, Professor, his discoverv 

 290. 



Galvanometer, 318. 



Gambart, M., his computation of 

 the elements of a comet, 347. 



Gardner, Mr., on the configuration 

 of land and water, 258. 



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

 bination of gases, 103. His esti- 

 mation of the length of a flash of 

 lightning, 282. 



Gensannc, M., his observations on 

 the heat of mines, 242. 



Giesecke, Sir Charles, on isothermal 

 lines, 260. 



Glass impermeable to heat, 210 et 

 scq. 



prism, 153. Note 190. 



, crown and flint, properties of, 



J58. 



, polarizing angle of, 179. Note 

 205. 



, vibrations of, 141. 



Goodricke, M., his opinion of varia- 

 ble stars, 365. 



Graham, his compensation pendu- 

 lum, 224. 



Gravitation, 3, 44. Note 5. 



, terrestrial. 4. 



-decreases from the poles to the 

 equator, 44. 



, the intensity of, 4. Note 13. 



of the planets and satellites, 5. 



Note 28. 



, universal, 6 et scg. 



, the nature of, 386. 



proportional to the mass, 5. 



Notes 27, 28: 



