IXDEX. 



495 



GOODR1CKE. 



(j-oodricke, Mr., variable stars dis- 

 covered by, 391 ; opaque bodies re- 

 presented as revolving round fixed 

 stars by, 394. 



Graham, Mrs., account of an earth- 

 quake by, 234. 



Graham's compensation pendulum,272. 



Gravitating force of the sun, 365, 

 424, 425. 



Gravitation, offices of, in the material 

 creation, 1,2; process of reasoning 

 in ascertaining the law of, 3 ; law 

 determining its intensity in the j 

 solar system, 5 ; complex action of, 

 by attraction in mass and in par- [ 

 tides, 6 ; increase of, towards the 

 poles of the earth, 45 ; calculations 

 founded on its increase, 49-51 ; in 

 a mine, its excess o.ver surface, 57 ; 

 action of, modifying tides, 92, 93 ; j 

 law, universally acting on matter, 

 105 ; the air s'ubject to, 117 ; in- 

 fluence of, in motions of the hea- 

 venly bodies, 382, 383; double 

 stars revolving by, 398 ; stellar 

 systems subject to, 400 ; influence 

 of, on nebulae, 416 ; a general law 

 of the visible creation, 424 ; mode 

 of its action, 425, 426. 



Gravity, centre of, in spheres, effect 

 ef impulses passing through, 7 ; of 

 the solar system, invariable plane 

 passing through, 23 ; straight line 

 described by, 24 ; action of, in deter- 

 mining the figure of the earth, 44, 

 45 ; definition irreconcilable with 

 the conservation of force, 354, 355 ; 

 question of its transmission, 355, 

 356. 



Great Bear, the nebulous zone passing, 

 416. 



Gobi, the, effect of the expansion 



of air over, 124. 



Greeks, astronomical observations of, 

 confirming results of analysis, 38. 



Greenland, ocean on the northern 

 coast of, 94. 



Greenwich, lunar distances computed 

 for, 43 ; quadrant of the meridian 

 passing through, furnishing a unit 

 of linear measure, 89 ; periodic 

 circuits of winds, 125. 



HARE. 



Grimaldi, coloured fringes bordering 

 shadows described by, 175. 



Groombridge, velocity of his proper 

 motion, 404. 



Grotthus, the transmission of voltaic 

 electricity investigated by, 298. 



Grove, Mr., copper and zinc plates 

 electrified by, 220 ; substances ra- 

 diating heat of different refrangi- 

 bilities enumerated by, 257 ; the 

 transmission of voltaic electricity 

 investigated by, 298 ; electric heat 

 tested by, 301, 302; remarks of, 

 on carbon, 302, 303; on the vol- 

 taic arc, 304, 305 ; remarks of, on 

 light and heat, 319 ; electric appa- 

 ratus improved by, 328 ; his de- 

 finition of the ethereal medium, 

 355. 



Grylli, supposed delicate sense of hear- 

 ing in, 132. 



Guanaxato, temperature of the silver- 

 mine of, 228. 



Gulfs separating stars, 390. 



Gum-guaiacum, chemically affected by 

 rays of the solar spectrum, 203 ; 

 condition of its sensibility to light, 

 206 ; effect of red rays on, 209 ; 

 used in experiments on parathermic 

 rays, 217, 218. 



Gum-lac, electrical intensity measured 

 by means of, 286, 287. 



Gymnotus electricus, the, 310. 



HAIDINGER, M., experiments of, 

 proving water an essential part of 

 crystals, 107. 



Hail, formation of, 270. 



Hales, his calculation of the amount 

 of surface exposed by the leaves of 

 a helianthus, 243. 



Hall, Mr., achromatic telescope con- 

 structed by, 165. 



Halley, elements of a comet's orbit 

 computed by, 362 ; return of his 

 comet, 363 ; changes in its aspect, 

 363, 364; records of, 365; no 

 solid nucleus in, 374 ; cause of its 

 luminous sectors, 376 ; Sir John 

 Herschel's observations on, 378. 



Hare, the, comet observed near, 372, 

 373. 



