INDEX. 301 



Phenic acid, i. 123 



Phenyle, chemical composition of, i. 128 

 Philomedusa Vogtii, a parasite of the medusae, ii. 100 

 Phonolite stone, on the Rhine, of what it consists, i. 206 

 Phosphorescence, property of, i. 66 



of insects, fish, and plants, i. 67 



of inorganic substances, i. 67 



essential difference between phosphorescence and fluorescence, i. 



67, 68 

 Phosphorescent light of luminous fungi, i. 264 



causes of this, i. 264 

 Phosphorus, i. 17 



whence procured, i. 17 



red allotropic, i. 17 



takes fire spontaneously in chlorine gas, i. 19 



atomic weight of, compared with that of hydrogen, i. 100 

 Photography, importance of the magnesium light in, i. 154 

 Phyllodoce, structure of, ii. 157 

 Phyllopoda, characters of the order, ii. 209 

 Physalia, or ' Spanish man-of-war,' structure, and modes of locomotion 



and reproduction of, ii. 111-114 

 Physaliidae, characters of the order, ii. Ill 

 Physomycetes, characters of the order, i. 296 

 Physophora hydrostatica, structure and habitat of, ii. 109, 110 

 Physophoridae, characters of the family of the, ii. 109-111 

 Pillwort, structure and habitat of, i. 371, 372 

 Pilularia globulifera, or pillwort, structure and habitat of, i. 371 

 Pilularia minuta, structure of, i. 371 

 Pinna, structure of the shell of, ii. 233 

 Pitch, manufacture of, i. 120 

 Planets, spectra of the, i. 157, 158, 161, 162 

 Plants, absorption of radiant heat by the perfumes of, i. 44 



weight of the perfumes, i. 45 



phosphorescence of, i. 67 



their synthetic process of rearing their fabrics, i. 96 



this process imitated by artificial means, i. 96 



chemical nature of the colouring matter of, i. 428, 429 

 Platinum, properties of, i. 5 



how vaporized, i. 30 



effect of electricity on, i. 32 



crystals of, formed artificially by electricity, i. 74 



its resistance to electricity, i. 90 



