360 GEOLOGY OF OHIO. 
Black damp is the carbonic acid gas of chemistry ; it is frequently 
called “stythe” by the English miners. Its effects on animal life are 
akin to those of the after-damp of an explosion. In its pure state it is 
a deadly poison, neither light nor life being capable of existing in it, and 
the miner’s lamp, when placed in an undiluted stratum of it, becomes 
instantly extinguished as though it were plunged in water. When only. 
10 per cent. of black damp is diffused through the air of mines, a light 
cannot be maintained; where a light ceases to burn, it is never 
safe for a miner to trust himself for any length of time. Black 
damp contains two atoms of oxygen, and one atom of carbon; its 
specific gravity is 1.524, common air being 1; the oxygen, by weight, 
forming 72.73 per cent, and the carbon 27.27 per cent. of the gas. 
Being thus considerably heavier than air, it occupies the floors of mines 
when in a pure state, but, like other gases, it readily diffuses itself with 
atmospheric air. 
The white damp of mines is the equivalent of carbonic oxide. This 
gas is much more deleterious to animal life than black damp, for air 
containing only 1 per cent. of white damp is unfit for human respira- 
tion, and if breathed fora few minutes will surely cause death. Un- 
like black damp, which ordinarily extinguishes the miner’s lamp before 
prostrating his energies, white damp will support combustion amidst a 
deadly atmosphere. Miners have been frequently found dead in air 
charged with white damp, while their lamps continued to burn with 
great clearness. The effects of this gas upon animal life are similar to 
those of black damp, and to the after-damp of explosion: The 
miner falls asleep, and, if not speedily removed, he dies. White 
damp is composed of 1 atom of oxygen and 1 atom of carbon. By 
weight this gas contains 56.69 per cent. of oxygen and 48.31 per 
cent. of carbon; its specific gravity is 975.195, being little less 
than the atmospheric air. Sulphuretted hydrogen gas is also fre- 
quently found in coal mines. It is called white damp by some miners, 
like carbonic oxide; it is, however, readily distinguished from carbonic 
oxide by its peculiar smell, which resembles that of rotten eggs. Sul- 
phuretted hydrogen consists of 1 atom of sulphur and 1 atom of hydro- 
gen; by weight it contains 94.15 per cent. of sulphur and 5.89 per cent. 
of hydrogen. This gas is met in abandoned workings in which iron 
pyrites is undergoing decomposition. It is also generated by contact 
of hydrogen with sulphur in a comminuted form. Like carbonic oxide, 
