PHYSIOGRAPHY. 117 



Carburetted Hydrogen Celestine. 



4. Carbonic acid is applied to a variety of purposes in medicine aod th 

 irtt. 



CARBURETTED HYDROGEN. Empyreumatic 



Hydrogen Gas. MOHS. 

 Amorphous. Transparent. Expansible. 

 Sp. gr.=0*5707. Odor empyreumatic. 



1. It burns with a bright flame, sometimes tinged with blue. 

 2. Analysis. 



Carbon 74-87 



Hydrogen 25-13 



3. It is developed from marshes and stagnant pools, and is also found 

 n volcanic countries. But its greatest source is certain coal mines and 

 salt springs. 



4. It is particularly abundant at Newcastle and Liege, where it is de- 

 nominated fire-damp. Numerous localities of it might be cited in Ohio 



land New York ; the more remarkable of which, however, is Fredonia, 

 40 miles from Buffalo, where it was first observed to bubble up from a 

 small stream ; but on boring a hole 1 inch in diameter through a soft fe- 

 tid limestone rock, of no great thickness, the gas left the stream, and was 

 discharged by this orifice. The brilliancy of the flame led to its being 

 adopted as a means of illuminating the village. A gazometer collects 30 

 cubic feet in 14 hours. 



CARBURET OF IRON. (See Plumbago.) 

 CARNELIAN. (See Quartz.) 

 CAVOLINITE. (See Ncphiline.) 

 CEYLANITE. (See Spinel.) 



CELESTINE. Prismatoidal Hal-Bar yte. 



MOHS. 



Primary form. Right rhombic prism. M on M' =? 

 104. 



