4047. Tests For Hydrogen

4047.    Tests For Hydrogen. Hydrogen is recognized by its combustibility ; by the pale color of its flame; by producing water only when burnt in air or oxygen; by extinguishing the flame of other bodies; and by exploding when mixed with half its weight of oxygen and fired. ( Cooley.)

4048. Carburetted Hydrogen

4048.    Carburetted Hydrogen. There are two leading gaseous compounds of carbon and hydrogen, known as carburetted hydrogen, and distinguished as light and heavy.

The light carburetted hydrogen is often abundantly disengaged in coal mines, and called methane, and fire damp. It consists of 2 equivalents of hydrogen and 1 of carbon, and burns with a yellowish flame. This gas also escapes in bubbles from the mud on the bottom of stagnant pools, combined with carbonic acid, from which it may be freed by passing through milk of lime, or a solution of caustic potassa. ( Cooley.) It has a specific gravity of about .559. ( Fownes.)

Heavy carburetted hydrogen is a combination of 2 equivalents of carbon and 2 of hydrogen ( 4 carbon and 4 hydrogen - Booth), and burns with a white luminous flame; it is a little lighter than air, having a specific gravity of .981. It is also called Ethine.

4049. To Obtain Light Carburetted Hydrogen

4049.    To Obtain Light Carburetted Hydrogen. When 2 parts crystallized acetate of soda, 2 parts dry hydrate of potassa, and 3 parts powdered quicklime, are strongly heated in a flask or retort, this gas is abundantly evolved, and may be collected over water. (See No. 4031 (Pneumatic Trough).)

4050. To Obtain Heavy Carburetted Hydrogen

4050.    To Obtain Heavy Carburetted Hydrogen. Heavy carburetted hydrogen is prepared by heating in a retort 1 part of alcohol with 6 or 7 of oil of vitriol until it blackens, and conducting the mixed gases through milk of lime, which retains the sulphurous acid; and afterwards through oil of vitriol, which absorbs water, ether, and alcohol. This may also be prepared by passing the vapor of boiling alcohol through a mixture of 10 parts oil of vitriol and 3 parts water, heated to ebullition (320° to 330° Fahr.), and purifying the vapor as before.

4051. Olefiant Gas

4051.     Olefiant Gas. A name given to heavy carburetted hydrogen, arising from its producing, in combination with chlorine, an oily-looking liquid. It is the presence of this gas which gives the illuminating power to coal-gas, which is a combination of fight, heavy, and other hydrocarbons.

4052. Sulphuretted Hydrogen

4052.      Sulphuretted Hydrogen. A compound of hydrogen and sulphur; a colorless gas, possessing a powerful odor of rotten eggs; specific gravity 1.171; it is absorbed by water, forming liquid sulphuretted hydrogen, or hydrosulphuric acid. It is a powerful poison. Being considerably denser than air, it may be poured from its generating bottle into cavities, a scheme successfully employed by M. Thenard to destroy rats in their holes, a method equally applicable to other vermin. It forms saline compounds with the alkalies, and the earths termed hydrosulphates or hydrosULphurets, and it precipitates metallic sulphurets from solutions of most of the metals ; hence its value as a test. Air containing 1/20000 part of pure hydrogen will sensibly blacken a piece of white paper, moistened with a solution of acetate of lead. Sulphuretted hydrogen is the active ingredient in the sulphurous mineral waters.