wunder · LibraryCHAPTER XX.. Carburetted Hydrogen Gas.
Read in the Wunder reader — freeCARBURETTED HYDROGEN GAS.
Q. What is CHOKE-DAMP?
A. Carbonic acid gas accumulated at the bottom of wells and pits. It is called CHOKE damp, because it chokes (or suffocates) every animal that inhales it. (see p. 264).
Q. What is marsh-gas or FIRE-DAMP?
A. Carburetted hydrogen gas accumulated on marshes, in stagnant waters, and coal pits; it is frequently called "inflammable air."
Q. What is CARBURETTED HYDROGEN GAS?
A. Carbon combined with hydrogen.
Q. How may CARBURETTED HYDROGEN GAS be PROCURED on marshes?
A. By stirring the mud at the bottom of any stagnant pool, and collecting the gas (as it escapes upwards) in an inverted glass vessel.
Q. What is COAL GAS?
A. Carburetted hydrogen extracted from coals, by the heat of fire.
Q. Why is carburetted hydrogen gas called FIRE-DAMP, or inflammable air?
A. Because it very readily catches fire and explodes, when a light is introduced to it.
Q. Why is carburetted hydrogen gas frequently called MARSH GAS?
A. Because it is generated in meadows and marshes from putrefying vegetable substances. (See ignis fatuus, p. 285).
Q. What gas is evolved by the WICK of a burning CANDLE?
A. Carburetted hydrogen gas: that is, the carbon and hydrogen of the tallow combine into a gas from the heat of the flame; and this gas is carburetted hydrogen, or inflammable air.
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?
A. 1st--Because flame will never pass through fine gauze wire: and
2ndly--Though the wire get red-hot, it will not ignite the gas; for carburetted hydrogen gas can be ignited only by flame.
(N. B. The interstices of the gauze wire must not exceed the 7th of an inch in diameter.)
Q. Why will not FLAME PASS THROUGH very fine wire-GAUZE?
A. Because the metal wire is a very rapid conductor of heat; and when the flame of burning gas in the lamp reaches the wire gauze, the heat (which is needful to produce flame) is conducted away by the wire, and the flame is extinguished.
Q. Does the gas of the COAL-PIT get THROUGH the wire gauze INTO the LANTERN?
A. Yes; but the inflammable gas ignites and burns inside the lamp: as soon, however, as this is the case, the miner is in danger, and should withdraw.
Q. Why is the miner in DANGER, if the gas ignites and burns in the INSIDE of the safety-lamp?
A. Because the heat of the burning gas will soon destroy the wire gauze, and then the flame (being free) will set fire to the mine.
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