Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 4, 1802).djvu/252

224] it merits the attention of farmers, who wish to improve moist meadows over-grown with moss.  TIN, or Stannum, one of the imperfect metals, which is obtained principally from the county of Cornwall, where it is sometimes dug up in a native or pure state; though more frequently mixed with a large portion of arsenic, sulphur, and iron. The crude ore is first broken to pieces, and washed; then roasted in an intense heat, which dissipates the arsenic; and afterwards fused in a furnace, till it be reduced to a metallic state.

Tin is the lightest and most fusible of all metals: it is of a greyish-white colour; has a strong, disagreeable taste; and, when rubbed, emits a peculiar odour. it is also remarkably malleable; and, when beaten into very thin plates, or tinfoil, is employed in covering. Farther, tin readily unites with copper, forming the compositions known under the names of, and Bell-metal: by immersing thin plates of iron into melted tin, they become coated, and are then termed Block-tin, or Latten; which is manufactured into tea-canisters, and various culinary utensils.

Tin is likewise of use in medicine, both in the form of filings, and in a state of powder, especially as a vermifuge: it has often successfully expelled the, which had resisted the power of many other drugs; but, the doss varying from a few grains to an ounce, it is one of those remedies which must be prescribed by the experienced practitioner.  TINCTURE, in general, denotes a solution of the more volatile and active parts of various bodies, from the three kingdoms of Nature, by means of a proper solvent: see. This term is, however more particularly applied to those spirituous preparations, which contain the resinous parts of vegetables, as well as their flavour and colour.

The usual solvents, employed for extracting the medicinal virtues of plants, are water, and rectified spirit of wine; the latter of which is frequently used for obtaining the aciive principles from resins and the essential oils, that yield them imperfectly to the former. With a view to make a tincture or elixir, the vegetable or other matter is usually bruised, put into a matrass, and the spirit is poured on it, to the depth of about two inches. The glass is then closed, and placed in a sand-heat for five or six days, or till the spirit become perfectly impregnated, and acquire a deep colour.—The quantity of a tincture, to be administered for one dose, varies according to its constituent parts; though it seldom exceeds a tea-spoonful, which is taken at such times as the nature of the complaint may require.  TINNING, is the process of coating copper vessels, chiefly used for culinary purposes: it is generally performed in the following manner:

If the copper be new, its surface is first scoured with salt and diluted sulphuric acid: next, pulverized resin is strewed over the interior part of the vessel; into which, after heating it to a considerable degree, melted tin is carefully poured, and a roll of hard-twisted flax is passed briskly over the sides and bottom, to render the coating uniform. For tinning old vessels, a second time, the surface is first scraped,