MINERALS. 
345 
which we have just described ; for instead of ex- 
ploding when a torch is presented to it, this gas im- 
mediately extinguishes the light. It prevails on 
the surface of all fermenting liquors, as well as in 
many mines, and has been known to prove fatal 
to persons who have incautiously descended into 
the vats of large breweries. In subterranean places 
that have been deprived of a free circulation of air, 
or that have been wholly shut up for any length of 
time, this pernicious gas is very apt to occur; and 
as an instance of its fatal effects we shall mention a 
circumstance which is recorded of some unfortunate 
persons in Scotland. 
Some colliers, working near an old mine that had 
been long closed up, happened inadvertently to 
open a hole into it from the pit where they were 
then employed. By great good fortune, they at 
that time perceived their error, and instantly fled 
for their lives. The next day, however, they were 
resolved to renew their work in the same pit, and 
eight of them ventured down without any great 
apprehensions ; but they had scarcely got to the 
bottom of the stairs that led to the pit, when, com- 
ing within the vapour, they all instantly dropped 
down as if they had been shot. Amongst these 
unfortunate poor men, there was one whose wife 
was informed that he was stiff] ed in the mine ; and 
as he happened to be next the entrance, she so far 
ventured down as to see where he lay. As she ap- 
proached the place, the sight of her husband in- 
spired her with a desire to rescue him, if possible. 
