Tinctura slyptica.

† Spir. vitri-oli tenuis.

‡ Acidum vi-triolicum Ph. Lond. & Ed.

|| Acidum vitriolicum dilut. Ph. Lond.

Acid, vitriol, tenue, vulgo Spiritus vi-trioli tenuis Ph. Ed.

If the long-neck, in the extrication of the acid from vitriol, happens to crack in the fire, the acid that rises after this period is found remarkably changed. It emits in the air suffo-cating vapours like the fumes of burning brim-stone, and rises in distillation with a heat not much greater than that which the hand can bear: to the taste it discovers little corrosiveness or acidity. Combined with alkaline salts, it loses its pungent odour; but on the addition of any other acid, it is disengaged from the alkali, so as to rife again in distillation as volatile and suffocating as-before. It destroys or whitens the blue and red colours of the flowers of plants; whereas, in its fixt state, like the other acids, it changes the blue to red, and heightens thole which are naturally red. This volatile spirit loses its suffocating odour, and resumes its corrosiveness, fixedness, and other qualities, by exposure to the air, which seems to carry off the inflammable principle whereon its volatility depended.

The fumes of burning brimstone are no other thanthe vitriolic acid in its volatile state; see Sulphur, If a little burning sulphur be sus-pended over some water in a close vessel till the fumes subside, and this repeated with fresh portions of sulphur, till about half a pound has been used to a quart of water, the liquor will be found strongly impregnated with the volatile suffocating acid, and in keeping for some time, if the vessel is not closely stopt, it will become exactly similar to water acidulated with the fixt acid. If a very large glass, open at bottom, be hung over the burning sulphur, in a damp place screened from wind, a part of the fumes will condense upon the sides of the glass, and run down in drops, which may be collected by placing a glass dish underneath: the acid thus obtained is called, from the shape of the vessel that has been generally used for condensing the fumes, spirit or oil of sulphur by the bell. The quantity of acid collected by this process is very small, greatest part of the fumes escaping: six-teen ounces of sulphur, in the most favourable circumstances, yield scarcely one ounce of phlegmatic spirit; though it is certain, that out of this quantity of sulphur, more than fifteen ounces are pure acid, of such strength, as to require being diluted with above an equal quantity of water to reduce it to the pitch of common spirit of sulphur; so that if sulphur could be burnt without the loss of any of its fumes, we might obtain double its weight of an acid of the ordinary strength. The process has lately been improved, by some particular per-sons, though not perhaps to this degree, yet so far as to afford at a very low price almost all the acid now fold under the name of oil of vitriol. The improvement consists chiefly in burning the sulphur in very large glass vessels, in the bottoms of which some warm water is placed, whose steam serves to collect and condense the fumes.

Spir. vitrioli volat. Stabl.

Aqua sulphu-rata, Gas sul-phuris vulgo.

Spir. sulph. per campa-nam.

The acid of vitriol or sulphur, largely diluted so as to be supportable or but gratefully tart to the palate, is the mod salubrious of all the mineral acids. It is mixed with watery in-fusions, spirituous tinctures and other liquids, as an antiphlogistic; as a restringent in he-morrhagies; and as a stomachic and corroborant in weaknesses, loss of appetite, and decays of constitution, accompanied with flow febrile symptoms, brought on by irregularities, or succeeding the suppression of intermittents by Peruvian bark. In several cases of this kind, after bitters and aromatics of themselves had availed nothing, a mixture of them with the vitriolic acid has happily taken place: the form commonly made use of is that of a spirituous tincture: six ounces of oil of vitriol are dropt by degrees into a quart of rectified spirit of wine, the mixture digested for three days in a very gentle heat, and afterwards digested for three days longer with an ounce and a half of cinnamon, and an ounce of ginger †; or a pint of an aromatic tincture drawn with proof spirit is mixed with four ounces of the strong acid ‡: these liquors are given from ten to thirty or forty drops, in any convenient vehicle, at such times as the stomach is most empty. A mixture of oil of vitriol with spirit of wine alone, in the proportion of one part of the former to three of the latter, digested together for some time, is used in France as a restringent in gonorrhoeas, female fluors, and spittings of blood.

* This acid, diluted with water, has been given internally with great success in the itch. It was first used for this purpose in the Prussian army in 1756, and has since been much employed in several parts in Germany. The dose recommended recommended is from an eighth to a fourth of a dram of the pure acid twice or thrice a day. It is said to succeed equally in the dry and most itch; and when given to nurses, to cure both themselves and their children.

† Elixir vi-trioli Ph. Ed.

‡ Elix. vitri-oli acidum.

Aqua rabel-liana vulgo EaudeRabel Ph Paris.

When oil of vitriol and rectified spirit of wine are long digested together or distilled, a part of the acid unites with the vinous spirit into a new compound, very volatile and inflammable, of no perceptible acidity, of a strong and very fragrant smell, and an aromatic kind of taste: this dulcified part, more volatile than the reft, separates and rises first in distillation, and may thus be collected by itself. The college of London directs a pound of oil of vitriol and a pint of rectified spirit of wine to be cautiously and gradually mixed (a great conflict and heat ensuing if they are mixed hastily) and set to distil with a very gentle heat till sul-phureous vapours begin to arise: that of Edinburgh orders the same quantity of the oil of vitriol to be dropt into four times as much of the vinous spirit, and the mixture to be digested in a close vessel, for eight days, previously to the distillation, with a view to promote the coalition of the two ingredients. The different proportions of the acid spirit to the vinous, in these prescriptions, make no material variation in the qualities of the product, provided the distillation is duly conducted; for the smallest: of the above proportions of acid is much more than the vinous spirit can dulcify, and all the redundant acid remains in either case behind. The true dulcified spirit rises in thin subtile vapours, which condense upon the sides of the recipient in straight striae: these are succeeded by white fumes, which form either irregular striae or large round drops like oil; on the first appearance of which, the process is either to be stopt, or the receiver changed. The spirit which these fumes afford, very different from the dulcified one, has a pungent acid smell like the fumes of burning sulphur: on its surface is found a small quantity of oil, of a strong penetrating and very agreeable smell, readily dis-soluble in spirit of wine, to a large proportion of which it communicates the smell and taste of the aromatic or dulcified spirit. The college of Edinburgh, in order to secure against any acidity in the dulcified spirit, order it to be rectified, by mixing it with an equal measure of water, in every pint of which a dram of salt of tartar has been dissolved, and drawing off the spirit again by a gentle heat* (a).