by Biett and others in tuberculous affections of the skin, in lepra, psoriasis, lupus, porrigo, &c.
Iodide of sulphur stains the skin like iodine, and is readily decomposed by contact with organic substances.
SULPHURA′TION. The process by which silk, cotton, and woollen goods, straw plait, &c., are subjected to the fumes of burning sulphur, or sulphurous acid, for the purpose of bleaching or decolouring them. On the large scale, this is effected in closed apartments, called ‘sulphuring rooms,’ to which sufficient air only is admitted to keep up the slow combustion of the sulphur. On the small scale, as for straw hats, bonnets, &c., a large wooden chest is frequently employed in the same way.
SUL′PHURET. Syn. Sulphide; Sulphuretum, Sulphidum, L. See Sulphide.
SULPHURET′TED HY′DROGEN (H2S). Syn. Hydrogen sulphide, Dihydric sulphide, Hydric sulphide; Hydrosulphuric acid. Sulphuretted hydrogen occurs in nature amongst the gaseous products given off by volcanoes, as well as in many mineral waters, amongst which may be instanced those of Harrogate, in England, of Moffat, in Scotland, and of Barèges, Eaux Bonnes, St. Sauveur, &c., in the Pyrenees. It is also evolved from decaying animal matter containing albumen, such as white-of-egg, as well as from putrisable animal and vegetable substances, when in contact with a soluble sulphate, and is always one of the gases present in the air of drains and sewers. Sulphuretted hydrogen may be procured by the direct union of hydrogen and sulphur, as by passing hydrogen into boiling sulphur. But this method of procuring it is rarely, if ever, adopted. The much readier process of acting upon a metallic sulphide by an acid constitutes the means by which the chemist almost invariably obtains this gas.
The details of the process are as follows:
1. About an ounce of ferrous sulphide, previously reduced to small pieces, is placed in a bottle, and then there is poured on to it a fluid ounce of sulphuric acid diluted with 8 times its bulk of water, when the following reaction ensues:—FeS + H2SO4 = H2S + FeSO4.
The gas which is immediately and copiously given off may be collected in an apparatus, a drawing and description of which are given below.
The diluted acid, having become cool, is poured through the bulb-shaped aperture down the glass tube upon the ferrous sulphide, and the evolved gas passing through the small intermediate wash-bottle into the bottle at the reader’s right hand, is absorbed by the water therein contained, the operation being continued until the water has become saturated with the gas. The glass tubes are connected with vulcanised india rubber, as shown in the above plate. Diluted hydrochloric acid is frequently substituted for sulphuric.