INDEX. 281 



Grasses, structure and mode of reproduction of, i. 385-387 

 Gravitation, force of, less powerful than that of molecular attraction, i. 



109 



Gravity, specific, of atoms, i. 100 

 Green dye, obtained from the buckthorn, i. 124 

 Griffithsia, structure, habitat, and organs of reproduction of, i. 233 

 Grimmiei, structure of the tribe, i. 329 



Grinnelia americana, structure and mode of reproduction of, i. 230, 239 

 Gromia oviformis, structure of, ii. 26, 27 

 Gromiae, structure of the genus, ii. 25-27 

 Guano, mauve dye obtained from, i. 125 



Guernsey, richness of the iodine obtained from the sea-weeds of, i. 258 

 Guinea worm, structure and mode of reproduction of, ii. 147 

 Gums, formation of, i. 422 



Gymnogramma rutsefolia, remarkable distribution of, i. 336 

 Gyrophora, structure of the genus, i. 308 



Hairs of plants, structure of, i. 411 



Halichondria panicea, mode of propagation of, ii. 60, 61 



Haliomma, structure of, ii. 21 



Haliotis splendens, or ear-shell, structure of, ii. 234 



Haliseris, structure of, i. 247 



Halogens, spectra of the, i. 146 



Halurus, structure and mode of propagation of, i. 233 



Hare's-foot fern, i. 351 



Hart's-tongue fern, caudex of, i. 340 



structure, habitat, and fructification of, i. 351, 352 

 Heart, and organs representing it in the lower animals, ii. 4 

 Heat generated by impetus, i. 27 



quantity of heat which would be generated if it were arrested in its 

 orbit, i. 27 



probable cause of the heat of the sun, i. 28 



effect of the absorption of heat on a body in expansion and contrac- 

 tion, i. 28 



specific heat, i. 28 



mechanical equivalent of heat, i. 29 



causes of the heat which is the motive force of the steam-engine, 

 i. 29 



reciprocal action of heat and electricity, i. 31 



