COAL MINING. 303 
occurred, though this was the extreme point of danger: a sudden motion 
of the body, or a quick lowering of the light would ignite the fire- 
damp. The art of ventilation at this time was so little understood, that 
as soon as mines began to make fire-damp copiously, the workings were 
abandoned. 
Sir Humphry Davy invented the miners’ safety-lamp in 1815, and 
presented it as a gift to the miners. After this discovery, mines which 
had been abandoned, owing to the presence of fire-damp, were reopened, 
and millions of acres of mining property, otherwise unworkable, were 
made available to mining enterprise, though, as the results show, too 
often at the terrible sacrifice of human life. 
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