Q. Why do coal-mines so frequently explode?
A. Because the carburetted hydrogen gas (which is generated in these mines by the coals) explodes, when a light is incautiously introduced.
Q. How can miners see in the coal-pits, if they may never introduce a light?
A. Sir Humphrey Davy invented a lantern for the use of miners, called “the Safety Lamp,” which may be used without danger.
Q. Who was Sir Humphrey Davy?
A. A very clever chemist, born in Cornwall. (1778—1829).
Q. What kind of thing is the safety lamp?
A. It is a kind of lantern covered with a fine gauze wire, instead of glass or horn.
Q. How does this fine gauze wire prevent an explosion in the coal mine?