PHYSIOGRAPHY. 85 



Nitrogen Nitro-Magnesite. 



1. It is very deliquescent, and soluble in water. On burning coals, it 

 melts slowly, with slight detonation, and dries; the residue does not after- 

 wards attract moisture from the air. It consists of lime 32-, nitric acid 

 57-44, water 10-56. 



2. It is found in silky efflorescences, in caverns of limestone in Ken- 

 tucky. 



8. It is employed in the manufacture of saltpetre. 



NITROGEN. Pure Nitrogen-Gas. 



Gaseous. Transparent. 

 Sp. gr. =0-9722. 



\. Nitrogen-gas extinguishes flame and animal life, and is destitute 

 of taste and smell. It is absoibablc by about 100 volumes of water. 



2. It is developed, in a state of purity, or nearly so, from the surface 

 of the ground, over an extent of four or five acres, in Hoosick, Rensse- 

 laer county, (N. Y.) becoming manifest wherever there is water. Also, 

 at New Lebanon Springs, in the immediate vicinity, but in smaller quan- 

 tities. It is evolved, in like manner, by many well known mineral 

 springs of other countries, as those of Cheltenham and Harrowgate. 



3. The origin of Nitrogen- gas has been attributed to the decomposi- 

 tion of atmospheric air, contained in cavernous rocks ; its nitrogen and 

 oxygen uniting to form nitric acid, which would leave an excess of ni- 

 trogen, equal at least to ten times the quantity required for the complete 

 saturation of the oxygen in the compound nitric acid. 



NITRO-MAGNESITE. MagnesianEarthy-Salt. 

 In deliquescent efflorescences. 

 Color white. 



1. It is very deliquescent; and consists, when pure, of 



Nitric acid 72 



Magnesia 28. 



2. It is found in limestone caves, accompanying the Nitrocalcite. 



3. It is said to be employed in the manufacture of saltpetre. 



NONTRONITE. 



Massive: in round shaped masses, composition impalpable. 

 Color straw-yellow. Opake. 

 VOL. II. 8 



