306 INDEX. 



Rosaniline, chemical composition of, i. 128 



Rosemary, amount of radiant heat absorbed by the perfume of i. 44 



Roses, otto of, amount of radiant heat absorbed by the perfume of, i. 44 



Rotalia, structure of, ii. 38 



Rotalia Beccarii, habitat and structure of, ii. 42 



Rotaline group of foraminifera, ii. 44 



Rotifer, common, structure of the, ii. 167 



Rotifera, characters of the, ii. 162 



mode of reproduction of the, ii. 162 



Rubia tinctorum, madder obtained from the roots of, i. 124 

 Rubidium, i. 3, 4 



atomic weight of, compared with that of hydrogen, i. 1 00 



one of an isomeric triad with caesium and potassium, i. 105 



M. Bunsen's discovery of the metal by spectrum analysis, i. 134, 

 135 



mode of distinguishing it from potassium, i. 135 



properties of, i. 136 



where found, i. 136 

 Ruby, i. 4 



Ruhmkorff's electro-magnetic induction apparatus, i. 32 

 Russulse, lactiferous vessels of, i. 263 

 Rust of wheat, i. 281 



Rye, probable cause of the mildew of, i. 297 

 Rytiphsea pinastroides, antheridia of, i. 243 

 Rytiphlaea tinctoria, antheridia of, i. 242 



Saffron, meadow, poisonous alkaloid obtained from, i. 427 

 Sagarta miniata, structure and habitat of, ii. 132 



its deadly weapons, ii. 132, 133 

 Salpa maxima, structure of, 226, 227 

 Salpa mucronata, vast shoals of, ii. 228 

 Salpa zonaria, young of, ii. 227 

 Salpi, their food, i. 205 

 Salpida?, characters of the, ii. 226-228 

 Salt, change of volume of, by chemical combination, i. 20 



partial decomposition of, by diffusion, i. Ill 



yellow coloured light produced by the combustion of, i. 132 



spectrum analysis of i. 134 



