Its ato

vy's views, can properly be considered as a true muriate. mic constitution Mr. Dalton believes to be one atom of acid and two atoms of ammonia. The notion of its being a compound of chlorine with the imaginary substance of ammonium, or a chloride of ammonium, appears not to be tenable t.

Muriate of ammonia exhibits the following properties:

(a) It is volatilized, without being liquefied or decomposed, or in other words may be sublimed. Sir H. Davy finds that it may even be passed, without alteration, through glass or porcelain tubes heated to redness. When, however, it is transmitted over ignited metals, it is decomposed into its gaseous elements.

(b) It is readily soluble in water, three parts and a half of which, at 60° take up one of the salt. During its solution much caloric is absorbed. In boiling water, it is still more soluble; and the solution, on cooling, shoots into regular crystals.

(c) It slightly attracts moisture from the air.

(d) On the addition of a solution of pure potash, or pure soda, the alkali is disengaged, as is evinced by the pungent smell that arises on the mixture of these two bodies, though perfectly inodorous when separate.

(e) Though generally considered as a neutral salt, yet, if placed on litmus paper and moistened, Berzelius observes, that the paper is reddened after some moments, as it would be by an acid.

(f) It is decomposed by barytes, strontites, lime, and magnesia,

Process for obtaining Solution of Ammonia in Water.

The following process is given by Mr. R. Phillips, as preferable to that of the London Pharmacopoeiat.

On 9 oz. of well-burnt lime, pour half a pint of water, and when it has remained in a well closed vessel for nearly an hour, add 12 ounces of muriate of ammonia, and about 3 pints of boiling water. When the mixture has cooled, filter the solution; and, having put it into a retort, distil off 20 fluid ounces. The solution will have the specific gravity 0.954, which is quite as strong as it can be conveniently kept. If the solution be required to be more strongly impregnated, this will be best effected, by passing ammoniacal gas through it, from a mixture of equal parts of powdered lime and muof ammonia, by means of an apparatus similar to that described e preparation of muriatic acid.

en a mixture of one part of powdered muriate of ammonia
rom one to two of powdered carbonate of lime (chalk), both
ly free from moisture, is distilled together in a retort, a solid
substance condenses on the inner surface of the receiver.
the sub-carbonate of ammonia ; and the process now descri-
hat by which, with the substitution of proper subliming ves-
sub-carbonate of ammonia is prepared for sale. This ope-
nishes an example of double affinity. The carbonic acid,

* Ure in Thomson's Annals, x. 211.
† Remarks on the London Pharm. p. 34.

being transferred from the lime to the ammonia, forms sub-carbonate of ammonia; and the muriatic acid, passing to the lime, composes muriate of lime.

ART. 4. Muriate of Barytes.

Muriate of barytes may be formed by heating pure barytes in chlorine gas, each measure of which disengages half a measure of oxygen gas from that earth. Or when barytes is heated in muriatic acid gas, the gas disappears, and the salt, which is produced, becomes redhot. But for purposes of experiment, muriate of barytes is best prepared, by dissolving either the artificial or native carbonate in muriatic acid much diluted; or, if neither of these can be had, the sulphuret. The iron and lead, which are occasionally present in the carbonate, and are dissolved, along with the barytes, may be separated by the addition of a small quantity of liquid ammonia, or by boiling and stirring the solution in contact with a little lime; or, which is still better, by solution of barytes in water. When filtered and evaporated, the solution yields regular crystals, which have most commonly the shape of tables, bevelled at the edges, or of eight-sided pyramids, applied base to base. They dissolve in five parts of water, at 60°, or in a still smaller quantity of boiling water; and also in alcohol. They are not altered by exposure to the atmosphere; not are they decomposed, except partially, by a high temperature. The sulphuric acid separates the muriatic; and the salt is also decomposed by alkaline carbonates and sulphates.

Fifty grains of ignited muriate of barytes give 68 of luna cornea It is composed,

Its atomic constitution, according to Mr. Dalton, is 1 atom of acid and 1 atom of base; and the crystals consist of 1 atom of dry salt and 2 atoms of water. Sir H. Davy considers the dry salt as a compound of 1 atom of barium weighing 65, and 1 atom of chlorine 33.5. Hence 100 parts should consist of

ART. 5.-Muriate of Strontites

May be obtained by following the same process as that employed in preparing the barytic salt. The solution affords long slender hexagonal prisms, which are soluble in two parts of water, at 60°; and to almost any amount in boiling water. In a very moist atmosphere they deliquiate. They dissolve in alcohol, and give a blood-red colour to its flame.

Fifty grains of dry muriate of strontites give 85 of luna cornea, and hence the salt must consist of 67.5 acid. This agrees very nearly with Kirwan's determination, but differs somewhat from Vauquelin's viz. 61 base and 39 acid. Stromeyer, who has lately examined this salt, makes it consist of

According to Sir H. Davy's view, it is constituted of 29 parts strontium and 21 chlorine, or of

Its atomic constitution, agreeably to this view, is one atom of metal weighing 45, and one atom of chlorine weighing 33.5. On the old theory, it should consist of one atom of strontites, and one atom of muriatic acid.

ART. 6. Muriate of Lime.

This salt may be prepared by dissolving carbonate of lime in muriatic acid, or by washing off this soluble part of the mass which remains after the distillation of the solution of pure ammonia from muriate of ammonia and lime. One hundred grains of carbonate give, ccording to Berzelius, 109.6 of fused muriate of lime.

The solution crystallizes in six-sided striated prisms, terminated very sharp pyramids. If it be evaporated to the consistence of a up, and exposed to a temperature of 32°, it forms a compact mass, posed of bundles of needle-shaped crystals, crossing each other usedly. The dry salt retains its acid at the temperature of ig

crystals dissolve in half their weight of cold water, and to an ed extent in boiling water, being, in fact, soluble in their warystallization. They deliquiate rapidly in the air, and enter sion when heated. After being melted by a strong heat, the

fused mass still contains water; for by ignition with iron filings, it yields much hydrogen gas. On the new theory of chlorine, however, this gas may proceed from the decomposition of muriatic acid. If fused in a crucible, and treated in the same manner as the nitrate of lime, the crystals yield a solar phosphorus, called, from its discoverer, Homberg's phosphorus. When mingled with snow, they produce intense cold, as has already been described.

Dry muriate of lime may be inferred, from an experiment of Dr. Marcet, to consist of

One hundred grains of fused muriate of lime give, according to Davy, 250 grains of luna cornea; according to Berzelius 287.5. From experiments on its synthesis, Berzelius states its composition to be

But, according to the theory of Sir H. Davy, the salt after being ignited, consists of 31 chlorine and 19 calcium, or of

This is also a deliquescent and difficultly crystallized salt. It has an intensely bitter taste; is soluble in its own weight of water, or in five parts of alcohol. Unlike the preceding muriates, it is decomposed, but not entirely by ignition.

According to Mr. Dalton, Muriate of Magnesia is constituted of 56.4 acid + 43.6 base; but from Dr. Wollaston's table of equivalents, it may be deduced to consist of 58 acid and 42 base. The VOL. I. Y y

compound of chlorine and magnesium, though supposed by Sir H. Davy to exist, has not yet been examined in a separate state. When heated, the combination, he remarks, is destroyed; the chlorine decomposes water, and escapes in the state of muriatic acid, and the oxygen of the water forms magnesia with the metal.

The muriates of magnesia and lime are generally contained in muriate of soda, and impart to that salt much of its deliquescent property. They impair, too, its power of preserving food. They are also ingredients of sea-water.

ART. 8.-Muriate of Alumine

May be formed by dissolving fresh precipitated alumine in muriatic acid; but the acid is always in excess. It is scarcely possible to obtain this salt in crystals; for, by evaporation, it assumes the state of a thick jelly. It is extremely soluble in water, and deliquescent when dry. In a high temperature it abandons its acid entirely. No compound (Sir H. Davy observes) exists, that can be considered as a compound of alumine and chlorine.

ART. 9.-Muriate of Glucine.

This salt is little known. Like all the salts of glucine, it has a sweet taste, and crystallizes more readily than the nitrate.

ART. 10. Muriate of Zircon.

Fresh precipitated zircon is readily dissolved by muriatic acid. The compound is colourless; has an astringent taste; and furnishes, by evaporation, small needle-shaped crystals, which lose their transparency in the air. It is very soluble in water and in alcohol. It is decomposed by heat, and by the saliva of the mouth. The gallic acid, poured into the solution, precipitates, if it be free from iron, a white powder. Carbonate of ammonia gives a precipitate, which is re-dissolved by an excess of the carbonate.

ART. 11. Muriate of Yttria.

This compound has a striking resemblance to nitrate of yttria. Like that salt it dries with difficulty, and attracts moisture from the air. It does not crystallize, when evaporated, but forms a jelly.