L 14 ] 



Plato, on the heavenly bodies, &c., 51 ; 

 interpretation of nature, 154; his 

 geognostic views on hot springs, 

 and volcanic igneous streams, 235, 

 236. 



Pliny, the elder, his Natural History, 

 55; on comets, 89; aerolites, 109, 

 110,118; magnetism, 173; attrac- 

 tion of amber, 182; on earthquakes, 

 201,202; on the flame of inflam- 

 mable gas, in the district of Pha- 

 selis, 220; rarity of jasper, 262; on 

 the configuration of Africa, 296. 



Pliny, the younger, his description of 

 the great eruption of Mount Vesu- 

 vius, and the phenomenon of vol- 

 canic ashes, 233. 



Plutarch, truth of his conjecture that 

 falling stars are celestial bodies, 122. 



Poisson, on the planet Jupiter, 46 ; 

 conjecture on the spontaneous igni- 

 tion of meteoric stones, 104, 105 ; 

 Zodiacal light, 130; theory on the 

 earth's temperature, 165, 166, 169. 



Polarization, chromatic, results of its 

 discovery, 33; experiments on the 

 light of comets, 90, 91. 



Polybius, 295. 



Posidonius, on the Ligyaii field of 

 stones, 102. 



Pouillet, on the actual source of at- 

 mospheric electricity, 343. 



Prejudices against science, how ori- 

 ginated, 17; against the study of 

 the exact sciences, \vhv fallacious, 

 20, 33. 



Prichard, his physical history of Man 

 kind, 362. 



Pseudo-Plato, 35. 



Psychrometer, 340, 347. 



Pythagoras, first employed the -word 

 Cosmos in its modern sense, 51. 



Pythagoreans, their study of the hea 

 venly bodies, 47; doctrine on co- 

 mets, 88, 89. 



Quarterly Review, article on Terres- 

 trial Magnetism, 186. 



Quetelet, on aerolites, 100; their pe- 

 riodic return in August, 113. 



Races, human, their geographical dis- 

 tribution, and unity, 360369. 

 Rain drops, temperature of, 21 7; mean 



annual quantity in the two hemi- 

 spheres, 342, 343. 



Reich, mean density of the earth, as 

 ascertained by the torsion balance, 

 162; temperature of the mines in 

 Saxony, 166. 



Reisch, Gregory, his ' Margarita Phi- 

 losophica,' 39. 



Remusat, Abel, Mongolian tradition 

 on the fall of an aerolite, 103; active 

 volcanoes in Central Asia, at great 

 distances from the sea, 244. 



Richardson, magnetic phenomena at- 

 tending the Aurora, 191 whether 

 accompanied by sound, 194; in- 

 fluence on the magnetic needle of 

 the Aurora, 195, 196. 



Riobamba, earthquake at, 199, 201, 

 203,209,211. 



Ritter, Carl, his ' Geography in rela- 

 tion to Nature and the History of 

 Man, 28, 49. 



Robert, Eugene, on the ancient sea 

 line, on the coast of Spitzbergen, 

 300. 



Robertson, on the permanency of the 

 compass in Jamaica, 174. 



Rocks, their nature and configuration, 

 225,226; geognostical classification 

 into four groups, 247 251 ; i. rocks 

 of eruption, 247, 251254; ii. sedi- 

 mentary rocks, 247, 248, 254, 255 ; Hi. 

 transformed, or, metamorphic rocks, 

 248, 256, 270; iiii. conglomerates, 

 or rocks of detritus, 270 272; their 

 changes from the action of heat, 259, 

 260; phenomena of contact, 259 

 269 ; effects of pressure and the ra- 

 pidity of cooling, 259, 268. 



Rose, Gustave, on the chemical ele- 

 ments, &c. of various aerolites, 119; 

 on the structural relations of vol- 

 canic rocks, 233 ; on crystals of feld- 

 spar and albite found in granite, 251; 

 relations of position in which gra- 

 nite occurs, 252270; chemical 

 process in the formation of various 

 minerals, 267 270. 



Ross, Sir James, his soundings with 

 27,600 feet of line, 151; magnetic 

 observations at the South Pole, 181 ; 

 important results of the Antarctic 

 magnetic expedition in 1839, 186; 

 rarity of electric explosions in high 

 northern regions, 345. 



