HYDROGEN. This remarkable gas is the tightest of all known bocliei: It maybe oh ained in several modes, but it is usually pro iured by the decomposition of water, by musing some substance to act upon it which affinity for its oxygen and none for the aydrogen, so that this element is separated, end asumes the elastic or gaseous state. Hydrogen is colourless, inodorous, Ind it has resisted all attempts which have ieen made to condense it by the united agency if cold and pressure. 1G0 culaie'inches weigh grains. This gas extinguishes lame by itself; hut when it meets with a >orter of combustion, as oxygen, it burns •eadily, and with a continuous but feeble lame, and much heat. When with ixygen, a taper causes immediate • and loud :xplosion attended with the formation of water by the combination of the gases. When mixed with oxygen gas, and the mixture gra dually burned into a small jet, intense heat is generated. When a very small jet is burned,
the flickering nature of the flame causes mu sical sounds when a tube of glass or metal or even of paper is held over it.
Hydrogen unites with all other elementary gaseous bodies, and forms with them com pounds of vast importance and utility : thus with oxygen it forms water; with nitrogen, ammonia ; with chlorine, hydrochloric or mu. riatic acid; with fluorine, hydrofluoric acid ; with bromine, hydrobromic acid ; with carbon it forms the fire-damp of coal mines, the liquid naphtha, and the solid caoutchouc, accord ing to the proportions and the mode of com bination.
It is needless to expatiate on the utility of hydrogen in the arts and manufactures, since scarcely any process goes on without its pre sence and immediate action.