CHAPTER XXI.. Phosphuretted Hydrogen Gas.

PHOSPHURETTED HYDROGEN GAS.

Q. From what does the very OFFENSIVE EFFLUVIA of CHURCH-YARDS arise?

A. From a gas called PHOSPHURETTED HYDROGEN; which is phosphorus combined with hydrogen gas.

Q. What is PHOSPHORUS?

A. A pale amber-coloured substance, resembling wax in appearance. The word is derived from two Greek words, which mean "to produce or carry light." ([Greek: phôs-pherein]).

Q. How is PHOSPHORUS OBTAINED?

A. By heating bones to a white heat; by which means the animal matter and charcoal are consumed, and what is left is called "phosphate of lime."

Q. How is PHOSPHATE OF LIME converted into PHOSPHORUS?

A. It is reduced to powder, and mixed with sulphuric acid; which (being heated and filtered) is converted into phosphorus.

Q. Of what are LUCIFER MATCHES made?

A. Of phosphorus; and above 250 thousand lbs. of phosphorus are used every year in London alone, merely for the manufacture of lucifer matches.

Q. Why does a PUTREFYING dead BODY SMELL so offensively?

A. From the phosphuretted hydrogen gas, which always arises from putrefying animal substances.

The escape of ammonia and sulphur contributes also to this offensive effluvia.

Q. What is the cause of the IGNIS FATUUS, Jack o'Lantern, or Will o'the Wisp?

A. This luminous appearance (which haunts meadows, bogs, and marshes) arises from the gas of putrefying animal and vegetable substances; especially decaying fish.

Q. What gases arise from these PUTREFYING substances?

A. Phosphuretted hydrogen gas from putrefying animal substances: and

Carburetted hydrogen, (or inflammable gas) from fermenting vegetable matters.

Some persons erroneously think that the AURORA BOREALIS, or Northern Lights, may be attributed to the same gases, burning in the upper regions of the air.

Q. How are these gases IGNITED on bogs and meadows?

A. By the electricity of the air, the rays of the sun, some accidental spark, the lamp of some traveller, or in some similar way.

And sometimes from the spontaneous combustion of some dung-heaps, &c. in the locality.

Q. Why does an ignis fatuus or Will o'the Wisp FLY from us when we RUN to MEET it?

A. When we run towards an ignis fatuus, we produce a current of air, which drives the light gas forwards.

Q. Why does an ignis fatuus run AFTER us, when we FLEE from it in fright?

A. When we run away from the ignis fatuus, we produce a current in the way we run, which attracts the light inflammable gas in the same course.

Q. Is not a kind of Jack o'Lantern sometimes produced by an INSECT?

A. Yes; a swarm of luminous insects sometimes passes over a meadow, and produces an appearance exactly like that of the ignis fatuus.

Q. May this meteoric appearance be attributed to any OTHER cause, besides those mentioned?

A. Yes; if many horses, sheep, pigs, or oxen, are pastured on a meadow, the animal vapour arising from them (strongly electrified by the air) will ignite, and produce a luminous appearance.

Q. May not many GHOST stories have risen from some ignis fatuus lurking about church-yards?

A. Perhaps all the ghost stories (which deserve any credit at all) have arisen from the ignited gas of church-yards lurking about the tombs, to which fear has added its own creations.