DESCRIPTIVE MINERALOGY 
CLASS I. 
GASEOUS MINERALS. 
These substances are sometimes found in a free state ; at others they are held in solution 
by water, under pressure, but are given out when the pressure is relieved. Some of them 
burn upon the application of a lighted taper; others do not. 
ORDER I. COMBUSTIBLE GASES. 
There are four of these combustible gases which have been found in nature, viz: 
1. Hydrogen. 3. Sulphuretted Hydrogen. 
2. Carburetted Hydrogen. 4. Phosphuretted Hydrogen. 
HYDROGEN. 
[From the Greek vSup, water , and ysvvuu, I generate; because it is a constituent of water.] 
Hydrogen Gas. Cleaveland. — Hydrogen. Shepard and Dana. — Reines Hydrogen-Gas. Mohs. — Hydrogene. 
Beudant. 
Description. Gaseous, colourless, inodorous, and transparent ; absorbed by water in very 
small quantity. It is the lightest substance known, its specific gravity being 68.8, compared 
with air at 1000.0. 
This gas burns with a feeble flame when in contact with the atmosphere, but it extinguishes 
burning bodies. When mixed with oxygen and fired with a lighted taper or with the electric 
spark, it explodes violently, and the result is the formation of water. 
