296 INDEX. 



Nitric acid, combination forming, i. 95 

 Nitrogen gas, i. 12 



combination of nitrogen with chlorine, i. 20 



absorptive power of, i. 39, 41 



fulminates compounds of, i. 92 



number of combinations of, with oxygen, i. 95 



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



one of the illuminants in coal gas, i. 118 



spectrum analysis of, i. 140, 145 

 in high temperature, i. 144 



binoxide of, combination forming, i. 95 



chloride of, catalysis of, i. 91 



iodide of, catalysis of, i. 91 



protoxide of, or laughing gas, combination forming, i. 95 

 Nitrous oxide, absorption of, radiant heat by, i. 41, 43 



combination forming, i. 95 



Noctiluca miliaris, structure and mode of propagation of, ii. 73, 74 

 Noctiluci, their food, i. 205 

 Nodosaria, characters of the genus, ii. 39 

 Nodosaria rugosa, shell of, ii. 28 



structure of, ii. 39 

 Nodosaria spinicosta, form of, ii. 28 



structure of, ii. 39 



Nostoc commune, wide distribution of, i. 212 

 Nostochinese, structure and habitat of, 211 



reproduction of, i. 212 



wide distribution of, i. 212 

 Nullipores, structure and habitat of, i. 142 

 Nummulites, structure of the, ii. 44-46 



circumstances favouring their existence in the Tertiary period, ii. 5!i 



Ocean, force exerted in the creation of the, i. 31 



Octoblepharum albidum, leaves of, i. 330 



Octopoda, structure of, ii. 245 



Octopus vulgaris, or poulpe, structure of, ii. 245-247 



Odonthalia, structure of, 242 



(Edogonian capillare, reproduction of, i. 216 



Oidium, structure and habitat of, i. 290 



Oidium Tuckeri, or vine mildew, fungus producing, i. 295 



