And he tells us that wood can become lignite, or wood-coal, by parting with its oxygen, in the shape of carbonic acid gas, or choke-damp; and then common or bituminous coal, by parting with its hydrogen, chiefly in the form of carburetted hydrogenthe gas with which we light our streets.

In mines of true coal, not only is choke-damp given off, but that more terrible pest of the miners, fire-damp, or explosive carburetted hydrogen and olefiant gases.

It is certain that in the production of asphalt, carbonic acid, carburetted hydrogen, and water are given off.

Dr. Daubeny found the mud-volcanoes of Macaluba giving out bitumen, and bubbles of carbonic acid and carburetted hydrogen.

In mentioning the constituents of the atmosphere, he adopts without explanation the loose statement of some of the books, placing carburetted hydrogen on the same footing as to constancy and amount with carbonic acid, and making no allusion to nitric acid.

Yet chemistry has shown, that, except in special localities, carburetted hydrogen occurs only as a slight trace, the existence of which in most cases is rather inferred than actually demonstrated, and that it has no important office to perform,while nitric acid shares with ammonia in the grand function of the nourishment of plants.

He shows, by a simple experiment, that the Davy lamp is not safe in a current of hydrogen or carburetted hydrogen gas, and that many lives may have been lost from the confidence of miners in its perfect safety.

A current of hydrogen or carburetted hydrogen gas steadily directed on the flame of the lamp from a bladder and stopcock, by cooling the wire gauze, brings the flame of the lamp through the gauze to the mouth of the stopcock, (even should there be six folds of gauze intervening.)

He shows also, by immersing the lamp, when cold and newly lighted, into a jar of dense hydrogen or carburetted hydrogen gas, or an explosive mixture with atmospheric air, that explosion takes place inside and outside of the lamp; whereas, when the lamp has burnt sufficiently long to heat the wire gauze, no explosion takes place on the outside of the lamp.

It is composed of 21 parts in weight of Oxygen and 77 of Nitrogen, with a little Carbonic Acid, Aqueous Vapor, and a trace of Carburetted Hydrogen.

An endeavor was made to obviate the difficulty by manufacturing a special gas for the motive power, as steam is produced for the same object, by distilling coal, carbureting air, producing water gas by the Dowson process, and by other equivalent processes.

They will carefully distill itextract its valuable juicesand will supply for combustion only its carbureted hydrogen and its carbon in some gaseous or finely divided form.

The fire-damp was known to be light carburetted hydrogen gas; but its relations to combustion had not been examined.