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Sulphuretted Hydrogen H3s

gas, water and sulphur

" SULPHURETTED HYDROGEN (H3S), a gaseous compound of hydrogen and sulphur, found abuncLuitly in nature in gases issuing from crevices in volcanic regions, and oc casionally in natural gas. It is one of the com mon products of decomposition of vegetable substances, especially those of the leguminous family. It occurs in illuminating gas, from which it is scrupulously removed at consider able expense. It is prepared on a large scale by heating together equal parts of vaseline or paraffin and sulphur.

Sulphuretted hydrogen is a colorless, in flammable gas, burning with a bluish flame, and having an extremely offensive odor, similar to that of rotten eggs. It is very poisonous; when inhaled in small quantity produdng nausea and headache, and in large quantity, asphyxiation. One part of the gas in 200 parts of air is fatal to horses, and one part of gas to 800 of air is fatal to dogs. It is soluble in water in the proportion of 4.4 volumes of gas to 1 volume of water at 32 F. At higher temperatures less of the gas is held in solution. Alcohol at 32 dissolves 17.9 times its own volume.

The aqueous solution of sulphuretted hy drogen is known as hydrosulphuric acid. It smells of the gas, and decomposes on standing, depositing sulphur. and the hydrogen oxidizing into water. Its solution in glycerine, how ever, keeps good for a long time.

The gas may be liquefied at ordinary tern peratures by submitting it to a pressure of 17 atmospheres that is, about 250 pounds to the square inch. Liquid sulphuretted hydrogen is a colorless, mobile liquid which freezes or soldifies at 117 F.. and boils at 79. In its liquid form it is nearly inert chemically.

Sulphuretted hydrogen is used in large quantities in the manufacture of sulphuric acid to remove the arsenic which is found in larger or smaller percentage in all acid madt from pyrites. It is also used to precipitate copper from solutions containing salts of copper, and for precipitating gold and silver from sweep ings and other waste material. In the chemist's laboratory it is one of the most valuable reagents.