Ammonia of which there are two sorts, the native and the factitious. The former, described by Pliny and. Dioscorides, was generated from the urine of camels, in the inns, or caravanseras, where the pilgrims returning from the Temple of Ju-piter Ammon, used to lodge; whence it derived its name. latter is a chemical preparation, formed either of the acetous or muriatic acids, combined with volatile alkali. A salt nearly of the same kind is thrown cat by Mount Etna. The, ancient sal ammoniac was said to the properties of cooling water, and dissolving

Great quantities of this concrete were formerly brought from Egypt, prepared by soot of animal dung ; tho at present we are principally supplied from our own man manufactorie, several of which are established in different parts of Britain: but that in the vicinity of Edinburgh is one of the most

Although the cheapest and most convenient method of preparing it is not generally known, yet it is conjectured to be chiefly farmed of a combination of sea salt and It is commonly crystallized round cakes , sometimes. in conical loaves. '.

best sort is colourless, almost transparent, and free from visible impurities. The taste of this salt is very sharp and penetrating. It dissolves in rather less than thrice its weight of water ; and upon evaporating part of the liquor concretes again into thin shining spicules, or plates, like feathers. In frosty weather, these are remarkably beautiful, and resemble trees, plants, etc..

Sal ammoniac, when pure, promotes perspiration, and in some -, increases the secretion of urine. A drachm of it, dissolved in water, if the patient be kept warm after taking it, generally proves sudorific. By moderate exercise in the open air, it beneficially operates on the kidneys; given in a large dose, it proves aperient; and in a still larger, acts as an emetic.

As a cooling and diaphoretic medicine, the sal ammoniac dissolved either in vinegar and water, or combined with small doses of the Peruvian bark, has often been attended with the best effects, when taken in fevers, and especially in intermittents, after the intestinal canal has been properly evacuated. Mr. C. Lynam, a medial practitioner in the metropolis, has formerly favoured the Editor of this work with an account of a cheap and expeditious manner of saturating the common solution obtained by dissolving this salt, in vinegar, with fixed air, or carbonic acid gas; which is a valuable addition to that liquor. His method is in effect as follows: take one ounce of pure sal ammoniac, and one pint and a half of distilled vinegar; put the latter in a decanter provided with a close glass-stopper then introduce the salt, previously broken into lumps, but not too small; as by plunging it too suddenly into the liquor, the extrication of the gas would be too quick, and a quantity of it be dissipated. Next, topper of the bottle should be tied over with a piece of leather, and the whole be left undisturbed'.

It would farther be useful, to add, on the top of the bottle, some weight or pressure, by which means the combination of the carbonic acid gas with the water will be greatly facilitated. After having stood a hours, the ammonia will be dissolved, and the carbonic acid absorbed by the liquor.

By this simple process, the ace-tated water of ammonia becomes strongly impregnated with fixed air, while it is almost entirely deprived of that disagreeable taste which is peculiar to this medicine, when prepared in the usual way.

Mr. Lynam speaks from experience, of the superior qualities this preparation possesses as a febrifuge; beside the very great advantage, that it tends to keep the bowels open, even under -the immediate influence of opiates. It likewise generally, agrees with weak and irritable stomachs, which can re-scarcely any other medicine.

This salt has also been employed externally in lotions and embrocations, for scirrhous and other indolent tumours; for removing warts and other excrescences, and in gar-garisms, for inflammations of the tonsilns..

Ammonia pura, or the caustic vegetable alkali, possesses uncommon alexiteric powers, in the cure of persons bitten by snakes, and other venomous animals. Sixtv drops of it, sufficiently diluted with water, make a moderate dose, which ought to be repeated according to the urgency of the symptoms. At the same time, the wound should be Washed with a similar mixture

It is positively asserted, that such treatment has been attended with" uniform success, when the patient was able to swallow the medi-cine, cine.