Sulphur is insoluble in water, but dissolves in alcohol, if both sub stances are exposed to each other in the state of vapour : on the addition of water, the sulphur is precipitated. It is dissolved by boil ing oil of turpentine ; the solution has a reddish-brown colour, and, on cooling, minute crystals of sulphur are deposited. It is readily taken up by chloride of sulphur, and is soluble in about three times its weight of bisulphide of carbon ; the elastic variety is, however, not so soluble. Sulphur is also soluble to a small extent in ether and in chloroform.
Sulphur is a bad conductor of heat ; it is very volatile, and when it is rubbed in the dark on a brick, or any other substance by which it is heated, though not sufficiently to inflame it, an extremely weak blue flame arises, exhaling a peculiar odour ; this flame is not, however, occasioned by combustion, it merely accompanies the evaporation of the sulphur, for a cold body held over it is covered with flowers of sulphur. When sulphur is heated, it begins to vaporise before it fuses ; at 600° Fahr. it is rapidly volatilised, and In close vessels is condensed withont change. The specific gravity of the vapour of sulphur is at 900° Fehr., but at 1900° Fahr. it is Its com bining volume below 1500° Fahr. is but at 1900° Fahr. it is 1. It unites directly with some metals to form sulphides.
When heated in the air sulphur quickly takes fire and burns with a pale blue flame, generating much heat.
The equivalent of sulphur is 16.
Cumpounds of Sulphur and 0.cygen are seven in number, namely Sulphurous arid (SO,) Sulphurous anhydride.—This gas escapes, in the gaseous state, from fissures in the ground in the neighbourhood of volcanoes. It is artificially obtained in the pure state on heating about two parts of mercury with three of strong sulphuric acid :— Copper clippings may be economically substituted for mercury, but as met with in commerce they generally contain matters that affect the purity of the gas. On the large scale, solution of sulphurous acid is preferable to the gas itself, and is manufactured directly from sulphur. The latter is burnt in a furnace, and the sulphurous acid produced cooled by passing through earthenware tubes surrounded by cold water. It is then made to ascend through a tall and wide wooden column packed with pumice-etone that has been digested in hydro chloric acid and well washed. In ascending the sulphurous acid meets with a stream of water, the flow of which is so regulated that a maturated solution shall flow off at the bottom of the column. It is
stored for use in a closed reservoir.
Sulphurous acid gas is colourless, and permanently elastic; that is, not condensed into a fluid or solid by exposure to common degrees of cold under the ordinary pressure. It condenses to the liquid state, however, on being passed through a tube surrounded by a freezing mixture of ice and salt. In this condition it may be preserved in her metically sealed tubes, on the interior of which, at 60° Fahr., it exerts a pressure of two and a half atmospheres. At Fehr. it freezes to a colourless, transparent, crystalline solid.
Sulphurous acid gas has a pungent and suffocating odour, being that experienced whenever sulphur is burned ; its taste is disagreeable and acid ; It extinguishes burning bodies, is not inflammable, and is fatal to animals. Water at 60' Fain% dissolves from 33 to 37 times its volume of this gas ; by heating the solution it is evolved unaltered. The solution possesses the smell of the gas itself ; and, like it, has the property of bleaching some vegetable and animal substances : hence the employment of the vapour of burning sulphur in whitening hops, silk, wool, and straw.
One hundred cubic inches of sulphurous acid gas weigh grains; its density therefore is about 2'22. Being so much heavier than sir it may be collected in vessels by displacement. GASES, COLLECTION or.) The aqueous solution of sulphurous acid, w en exposed to oxygen, slowly combines with it, and the result is sulphuric acid ; but unless moisture be present, no combination takes place between these two gases.
Sulphurous acid combines with various hazes to form salts, which aro called sulphites. When, for example, this gas is passed into an aqueous solution of ammonia, they re wily combine, and the resulting salt is sulphite of ammonia, which may be obtained in prismatic crystals. It is very soluble in water, and produces much cold during solution; by exposure to the air it attracts oxygen, and becomes sulphate of ammonia. When, however, dry sulphurous acid gas and dry ammoniacal gas are brought into contact, deep yellow-coloured crystals are formed, which have been termed sulphitammon, or im properly sulfamide; they contain the elements of sulphurous acid and ammonia combined, but in a different mode to that which forms anhydrous sulphite of ammonia. By exposure to the air sulfamide becomes white, deliquesces, and gradually becomes sulphate and hypo sulphate of ammonia.