There can be little doubt but that the "bright and vigorous flame" which the writer describes, proceeded from what we now call carburetted hydrogen gas.

Dr. Priestley states, that "Mr. Boyle was the first who discovered that what we now call fixed air and inflammable air are really elastic fluids, capable of being exhibited in a state unmixed with common air."* But although the existence of these elastic fluids, as distinct substances, may have been known to Mr. Boyle, there seems to have been no evidence of either of them having been obtained from coal by actual distillation, until the time of the ingenious Dr. Stephen Hales. His experiments, for the production of elastic fluids from a great number of substances, were various and ingenious; and are related in the first volume of his Vegetable Statics, published in 1726. From the "distillation of 158 grains of

* See Dr. Priestley's Observations and Experiments on Air, Vol. I. p. 3, 1790. To this edition is prefixed a Dedication to the present King, then Prince of Wales, in which enlarged philosophical views are fervently and forcibly expressed. He urges him, when he should attain the supreme power, to make his glory and happiness consist in promoting the interests of science, commerce, and the arts; and to how great an extent have the Doctor's benevolent wishes been realized!

+ Lavoisier has given a very clear and admirable abstract

Newcastle coal, he states that he obtained 180 cubic inches of air, which weighed 51 grains, being nearly one-third of the whole." But the object of his experiments appears to have been rather the production of the gas from coal, and to ascertain its elasticity, than to inquire into its inflammable and other properties, which, though now deemed the most useful and important, seem to have had no attention bestowed upon them till several years afterwards. Perhaps it is a little remarkable that these qualities should not have been particularly noticed by a person possessing so much sagacity and attentive observation.

CHAPTER II.

A REMARKABLE APPEARANCE OF DAMP AIR IN

A COAL PIT BELONGING TO SIR JAMES LOWTHER, BART.

Some interesting circumstances, relating to the properties of coal gas, are detailed in a paper contained in the Philosophical Transactions for 1733; and the communication is important, inas

of Dr. Hales's experiments on the Elastic Fluids, in his Essays, Chemical and Physical, translated by Thomas Henry, F. R. S., 1776.

much as the writer notices the remarkable facts, that "it will not take fire except by flame;" and that "sparks do not affect it."* The article is denominated, "An Account of the Damp Air in a Coal Pit of Sir James Lowther, sunk within Twenty Yards of the Sea." As this account contains some striking facts relating to the inflammability and other properties of coal gas, it is deserving of particular attention. The following is the writer's own narration :

"Sir James Lowther having occasion to sink a pit near the full sea-mark for the draining one of his principal collieries near Whitehaven, in the county of Cumberland, which was known would be near 80 fathom in depth to the best seam of coals, which is three yards thick; the work was carried on day and night very successfully, through several beds of hard stone, coal, and other minerals, till the pit was sunk down 42 fathom from the surface, where they came to a bed of black stone, about six inches thick, very full of joints and open cliffs, which divided the stones into

* Before the invention of Sir Humphrey Davy's Safety Lamp, this property of the gas gave rise to a variety of contrivances for affording the miners sufficient light to pursue their operations; and one of the most useful of these inventions was a mill for producing light by sparks elicited by the collision of flint and steel. Sir Humphrey Davy mentions some others in his work on the Safety Lamp.

pieces of about six inches square, the sides whereof were all spangled with sulphur, and in the colour of gold. Under this black stone lies a bed of coal two feet thick. When the workmen first pricked the black stone bed, which was on the rise side of the pit, it afforded very little water, contrary to what was expected, but instead thereof, a vast quantity of damp, corrupted air, which bubbled through a quantity of water, then spread over that part of the pit, and made a great hissing noise; at which the workmen, being somewhat surprised, held a candle towards it, and it immediately took fire upon the surface of the water, and burned very fiercely; the flame being about half a yard in diameter, and near two yards high, which frightened the workmen, so that they took the rope and went up the pit, having first extinguished the flame, by beating it out with their hats. The steward of the works being made acquainted with it, went down the pit with one of the men, and holding a candle to the same place, it immediately took fire again as before, and burnt about the same bigness; the flame being blue at the bottom, and more white towards the top. They suffered it to burn for nearly half an hour, and no water being drawn in the time, it rose and covered the bottom of the pit near a yard deep, but that did very little abate the violence or bulk of the flame, it still continuing to

burn upon the surface of the water. They then extinguished the flame as before, and opened the black stone bed near two foot broad, that a greater quantity of air might issue forth, and then fired it again; it burned a full yard in diameter, and about three yards high, which soon heated the pit to so great a degree, that the men were in danger of being stifled, and so were as expeditious as possible in extinguishing the flame, which was then too strong to be beaten out with their hats ; but with the assistance of a spout of water, of four inches in diameter, let down from a cistern above, they happily got it extinguished without further harm. After this no candles were suffered to come near it till the pit was sunk down quite through the bed of black stone; and the two foot coal underneath it, and all that part of the pit, for four or five feet high, was framed quite round, and very close jointed, so as to repel the damp air, which, nevertheless, it was apprehended, would break out in some other adjoining part, unless it was carried off as soon as produced out of the cliffs of the stone; for which end a small hollow was left behind the framing, in order to collect all the damp air on one side of the pit, where a tube of about two inches square was closely fixed, one end of it into the hollow behind the framing, and the other carried up into the open air, four