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18 . Miscellaneous Articles.
There is scarcely a profession or trade, however rudely con-ducted, that does not, in some degree, require the union of che-mical and mechanical science. And under this head, may hecomprised a short account of such chemical substances, made inScotland , as are afterwards employed in other aits and manu-factures, or form a part of the compounds of the Materia Me-dica; and next, some notice shall be taken of the trades and oc-cupations, or such mechanical arts as have not been fully de-scribed in the previous part of this chapter.
1. Sidphv y ric Acid .—This acid is termed, in common lan-guage, oil of vitriol, and is produced by the combustion of sul-phur and nitre in close vessels lined with sheet lead. Its stand-ard specific gravity is 1,850, or nearly double that of water;and it is sent to market in large glass bottles, contained in bas-kets of wicker-work.
It is more than half a century since vitriol works were erectedin the west of Scotland ; and those at present carrying on are si-tuated near Glasgow, —at Woodstde, St Rollocks, Napier’s Hall,Port Dundas, and Carntyne. There are also several in the east-ern districts, as at Burntisland in Fife , Prestonpans in East Lo-thian, Carriden parish in West Lothian, and Boroughmuir nearEdinburgh . This acid is extensively used in the Scotch chemi-cal manufactures, particularly in bleaching and calico-printing ;and a considerable quantity is exported to Ireland .
The success attending the manufacture of this article has sti-mulated the proprietors to extend their researches to other branch-es of chemical science; and at present there are a greater num-ber of intelligent practical chemists in Scotland , in proportion tothe population, than perhaps in any other country in the world.
2, Muriatic Acid .—This acid is obtained from the decomposi-tion of the muriate of soda, or common salt, by means of sul-phuiic acid, with which it is mixed in the retort, and distilled.
The first application of muriatic acid by bleachers, was forextracting iron mould from cloth ; and the next was, for obtain-ln g from it and manganese, the bleaching liquor; but in thisproce'S it is now superseded by sulphuric acid. It is, however,still used for clearing the gold ends of muslin goods ; and by®yers and calico-printers, for a vast variety of purposes in theirrespective arts.
3. Oxymuriatic Acid .—This acid is produced from manganese,mlphuric acid, and sea-salt, subjected to the process of distiila-ll °n. Its most valuable property is its rapid action on vegetablesubstances, which it speedily whitens or bleaches. There wereejections to the preparation and use of this acid in a liquidstate; and it was combined with vegetable alkali. But as pot-. es were expensive, a cheap substitute was found in lime, which,s now the material used for neutralizing the oxymuriatic acid.