502 



INDEX. 



GERBERT 



Gerbert introduces Arabic numerals into 

 Europe, 46 



Germany, Imperial Academy in, 124 



Gesner, his cabinet and garden, 67 ; his 

 history of animals, 67 ; his botanical 

 classification, 68 



Gilbert, first experiments on electricity, 74 



Gioja discovers manner's compass, 53 



Glacial period, 448 



Glacier, illustration of a, 449 ; carrying 

 blocks to the Jura, 450 



Gladstone, Dr., his life of Faraday, 374 



Glass, angle of polarization of light from, 

 323 ; index of refraction for, 106 ; dif- 

 ferent dispersive powers of, 166 



Glasses, musical, 272 



Glen Tilt, granite veins in, 221 



Gnomon at Alexandria, 28 



Goethe on metamorphosis of plants, 414 ; 

 on discussion between Cuvier and St. 

 Hilaire, 432 



Gold separated from amalgam by Paracel- 

 sus, 70 



Gottingen University founded, 195 



Graebe cited, 41? 



Graham, Dr., on diffusion of gases, 363 



Graham on variations of magnetic needle, 

 380 



Granite, Hutton on formation of, 220; 

 veins in Glen Tilt, 220 



Gravitation, law of, explained, 145-150 ; 

 discovered by Newton, 147 ; its action 

 on the planets, 149 : decreases with the 

 square of the distance, 150; problems 

 explained by, 151 ; holding distant stars 

 together, 284 



Graecus, Marcus, discovers gunpowder, 42 



Gratz, Kepler professor at, 93 



Greece, Roman conquest of, 35 



Greek colonies in Ionia, 8 



Greeks deficient in natural knowledge, 8 ; 

 believed the sun moved round the earth, 

 19 ; knew electric nature of amber, 75 ; 

 general remarks on science of the, 35 



Grew on vegetable anatomy, 137 ; on 

 stomates, 138 



Grove cited, 4^79 



Guericke's air-pump, 119; Magdeburg 

 hemispheres, 120 ; first electrical ma- 

 chine, 122 ; his experiments on electri- 

 city, 123 



Gunpowder known to the Arabs, 42 



Gutenberg, John, the printer, 55 



HALES, Dr., on gases, 225; on water 

 in plants, 193 



Hall, Asaph, on satellites of Mars, 311 

 Hall, Mr. C. More, on flint and crown 



glass, 166 



Hall, Sir J., on pelted rocks, 220 

 Halle, Dr., pleads for Lavoisier's life, 238 



HUGGINS 



Haller, early life of, 195 ; on contraction of 

 the muscles, 196 ; on comparative aii.i- 

 tomy, 196 



Halley, Ins method of measuring transit;, 

 155 ; observes transit of Mercury, ijr^^ 

 predicts the return of a comet, 159 



Harding discovers Juno, 300 



Harvey discovers circulation of the blood, 

 ir8 ; on development of the chick, 112 



Hawksbee's electrical machine, 121 



Heat, Bacon's examination of, 102 ; early 

 theories about, 349 ; produced by friction, 

 350; latent, 240, 3^3; Joule's experi- 

 ments on, mechanical equivalent of, 

 354 ; converted into motion, 358 ; pro- 

 duction of electricity by, 378 



Heat-rays discovered, 330 



Heavy bodies, Galileo on motions of, 79 



Helmholtz cited, 363 ; on conservation of 

 energy, 360 ; theory of colour, 328 



Henry brothers photograph an unseen 

 nebula, 347 



Hercules, motions of our solar system to- 

 wards, 285 



Hermes and hermetic philosophers, 41 



Hero's engine, 244 



Herophilus on muscles, nerves, and the 

 pulse, 26 



Herschel, Sir W., 281 ; discovers Uranus 

 and receives a pension, 283 ; on binary 

 stars, 283 ; on nebulae, 284; on motion of 

 solar system through space, 285 ; dis- 

 covers heat-rays, 330 ; on cause of sun- 

 spots, 379 



Herschel, Sir J., work in astronomy, 305 ; 

 on spectrum analysis, 336 



Herschel, Miss C., her brother's assistant, 

 286 



Herschel, Mr. A., on spectrum of falling 

 stars, 345 



Hiero's crown, Archimedes on, 22 



H iggins on chemical law of proportions, 400 



Hipparchus, astronomy of, 29 ; discovers 

 precession of equinoxes, 30 



Hippocrates the father of medicine, 14 



Hirn, M., his experiments on heat con- 

 verted into motion, 358 



Hodgson, M., on outbreak on a sun-spot, 381 



Hoffmann, Dr., cited, 410 



Homology, St. Hilaire on, 432 



Hooke, one of the founders of the Royal 

 Society, 123 ; on air-pump, 126 ; on com- 

 bustion, 128 ; on geology, 215 



Hooker, Sir W., on botany, 421 



Horrocks observes transit of Venus, 154 



Horse, ancestors of the, 462, 476 



Huen island, Tycho's observatory on, 76 



Huggins, Dr., on spectrum analysis of the 

 stars, 343 ; of nebulae, 344 ; measured 

 movement of Sirius, 346 ; on spectrum o/ 

 a comet, 345 



