Phosphuretted hydrogen gas may be dissolved in about four times its bulk of distilled water, at 44° Fahrenheit, and imparts to it a bitter taste, and strong un pleasant smell. This solution speedily converts the oxides of lead and mercury, and nitrate of silver, into phosphurets of those metals. Nitrates of lead, mercury, and arsenic, and sulphates of copper and iron, are acted upon by it more or less slowly ; but some of the posphurets then formed are changed, by standing some time, into phosphates.
The ignis fatuus, or jack with a lan tern, is supposed to be produced by this gas, arising from the putrefaction of ani mal substances in swampy places.
GAS, tulphurelted hydrogen. This gas, formerly teamed hepatic air, may be ob tained, by adding dilute muriatic acid to a solution of sulphuret cf potash or of soda, which evolves it with violent efferves cence t or by pouring diluted sulphuric or muriatic acid on sulphuret of iron, Sul phur and iron mixed together with a tle water, likewise afford it by distillation.
Sulphuretted hydrogen is particularly characterized by its offensive smell, re sembling that of rotten eggs. Like the other compounds of hydrogen, it deto nates if mixed with oxygen or atmosphe ric air, and then fired, and burns silently, if inflamed as it comes in contact with them from a small aperture. If three parts of it be mingled with two of nitrous gas, the mixture burns with a yellowish green flame.
This gas is decomposed by oxymuriatic acid gas, by sulphurous acid gas, or by being kept mixed with atmospheric air, and its sulphur is precipitated. If passed through ignited charcoal, it is converted into carburetted hydrogen gas. It preci pitates all metallic solutions, except those of iron, nickel, cobalt, manganese, tita nium, and molybdxna. It tarnishes sil ver, mercury, and other polished metals, and immediately blackens white paint.
This gas is absorbed by water, which at 55° takes up .86 of its bulk, and at 85° only .78. The solution exposed to the air becomes covered with a pellicle of sulphur ; and deposits sulphur even in well corked bottles. A few drops of ni tric or nitrous acid likewise precipitate the sulphur.
It is remarkable that sulphuretted hy drogen, which contains no oxygen, con sisting, according to Thenard, of 29 hy drogen, and 71 sulphur, should possess the properties of an acid, reddening lit mus paper, and uniting with the alkalies and all the earths, except alumina and zircon. These compounds are soluble,
and most of them are susceptible of crys tallization. They are at first colourless, hut by exposure to the air become green, or of a greenish yellow, and deposit sul phur. At length, however, the solution again becomes colourless, and the base is found ultimately converted into a sulphate. Acids disengage their sulphuretted hy drogen gas. Vauquelin, having lixiviated a considerable quantity of soda manufac tured in France, found, after some weeks, a white transparent salt, crystallized in te trahedral prisms, terminated by quadran gular or octangular pyramids. Its taste was acrid and intolerably bitter, and it - had a slight hepatic smell. It did not precipitate any of the earthy salts, except those of alumina, zircon and yttria. Some of the German chemists have classed it as an acid, by the name of the hydrothian.
The waters called sulphurous, or he , patic, as those of Harrowgate, are tions of this gas. They are recommended as alteratives in cutaneous against worms, in gout and jaundice, and as deobstruents ; but they are said to have been very injurious in dropsy.
Gxs, muriatic acid. Muriatic acid exists in a separate state only in the form of gas, but its attraction for water is so strong, that it can be received and confined only over mercury. According to Kirwan, water absorbs rather more than 420 times its bulk, and is augmented by it about one third : in Dr. Thomson's experiments it took up 515 times its bulk at 60° Fahren heit. It liquifies ice very rapidly, and the temperature is lowered. It has a pungent smell, is fatal to animals, and extinguishes flame, first imparting to it a greenish tinge. Its bulk is increased by a succes sion of electric shocks, which Mr. Henry has shewn to arise from the decomposi tion of water, of which he infers, from his experiments, 60 grains hold 1.4 in solu tions. On its coming into contact with at mospheric air, a white cloud is produced. Brisson gives its specific gravity, atmos pheric air being 1000, at 1430, Henry at 1730, Kirwan at 1929. For its other pro perties, see MURIATIC ACID.