2. Chlorate of Strontites may be obtained by the direct action of chloric acid on carbonate of strontites. It is a deliquescent salt, having an astringent taste, and communicating to the flame of alcohol a fine purple tint.

3. Chlorate of Lime-To the account of this salt, I think it proper to premise, that considerable uncertainty appears to me still to exist respecting its composition. It is even doubtful whether the substance, formed by exposing dry hydrate of lime to chlorine gas, is any thing more than a compound of that hydrate with chlorine. This compound derives importance from its application to the art of bleaching; for its solution in water, even when there is no excess of chlorine, possesses bleaching properties; and produces whiteness in the unbleached part of goods, without destroying any delicate colours which they may contain. The dry compound, formed from hydrate of lime and chlorine gas, is extremely deliquescent; liquefies at a low heat; and is soluble in alcohol. It produces much cold by solution, and a sharp taste in the mouth. Its composition and properties have been investigated by Mr. Dalton, in two memoirs published in the 1st and 2d volumes of Dr. Thomson's Annals. He finds that the dry salt is a compound of two atoms of lime, one of acid, and six of water. By solution, one half of the lime is deposited, and a compound of one atom of lime and one of acid is dissolved by the water. The dry salt is much impaired by being long kept. It contains per cent. according to Dalton,

For an account of the remaining salts formed with chloric acid, Mr. Chenevix's paper in the Philosophical Transactions for 1802, and Vauquelin's memoir in the 95th volume of Annales de Chimie, may be consulted.

SECTION X.

Nitro-Muriatic Acid.

id may be formed most commodiously by mixing two parts of colourless nitric acid with one of liquid muriatic acid. oys only one of nitric to four of muriatic acid. Though e both perfectly pale, yet the mixture becomes of a deep

red colour, a brisk effervescence takes place, and pungent vapours of chlorine are evolved.

Considerable light has been thrown on the nature of this acid by the experiments of Sir H. Davy, who has rendered it probable that its peculiar properties are owing to a mutual decomposition of the nitric and muriatic acids, the oxygen of the former uniting with the hydrogen of the latter, in consequence of which water, chlorine, and nitrous acid, are the results. For every 101 parts in weight of real nitric acid (equivalent to 118 of hydro-nitric acid) which are decomposed, 67 parts of chlorine, he calculates, are produced. According to this view, it is not correct to say that aqua regia oxidates gold or platinum, since it merely causes their combination with chiorine. By long continued and gentle heat, nitro-muriatic acid may be entirely deprived of chlorine, and it then loses its power of acting on gold and platinum.

The nitro-muriatic acid does not form, with alkaline or other bases, a distinct genus of salts, entitled to the name of nitro-muriates; for, when combined with an alkali, or an earth, the solution yields, on evaporation, a mixture of a muriate and a nitrate; and metallic bodies dissolved in it yield muriates only. The most remarkable property of nitro-muriatic acid (that of dissolving gold, from whence it has been called aqua regia) will be described in the chapter on that metal.

SECTION XI.

Murio-Sulphuric Acid.

MURIATIC acid gas is absorbed in considerable quantity by sulphuric acid. The compound has a brown colour, and when exposed to the air emits copious white fumes. It has no particular use.

By the action of a mixture of fuming muriatic acid on sulphuret of carbon, Berzelius obtained a solid white crystalline body, resembling camphor, and possessing some remarkable properties. Its analysis afforded

It appears, therefore to consist of two atoms of muriatic acid, one of sulphurous acid, and one of carbonic acid.

* Journal of Science, &c. i. 67.

VOL. I-Zz

APPENDIX.

DESCRIPTION OF THE PLATES.

PLATE I.

FIG. 1. (a) A plain retort, the neck of which is shown introduced a proper length into the mouth of a plain receiver b. The dotted lines at c show the receiver with the addition of a tubulure, into which either a stopper, or bent glass tube, may be occasionally fixed.

FIG. 2. A glass alembic; a the body, and b the head, which are ground so as to fit accurately, and may be separated when necessary. The head b is so shaped, that any liquid, which may be condensed, collects into a channel, and is carried by the pipe c into the receiver.

FIG. 3. A separator, for separating liquids of different specific gravities. It is furnished with a ground stopper at a, and a glass stop-cock at b. The vessel is filled with the liquids that are to be separated (oil and water for example), which are allowed to stand till the lighter has completely risen to the top. The stopper a is then removed, and the cock b opened, through which the heavier liquid descends; the cock being shut, as soon as the lighter one is about to flow out.

FIG. 4. A glass vessel, termed a mattrass, useful for effecting the solution of bodies, which require heat before they can be dissolved, or long continued digestion, see vol. i. p. 31. The upper extremity of the long neck generally remains cool, and allows the vessel and its contents to be shaken occasionally.

FIG. 5. A glass bottle with a very thin bottom, and a projecting ring round the neck for suspending it over a lamp. These are useful for effecting solutions on a small scale.

FIG. 6. An apparatus contrived by Mr. Pepys, for ascertaining the quantity of carbonic acid discharged from any substance by the addition of an acid. It consists of a bottle closed by a ground stopper. This stopper is perforated, and forms the lower part of a tube, which is twisted into the shape of a still-worm. In this worm, any water that escapes along with the gas, is condensed, and falls down again into the bottle. The experiment is made precisely as descri

bed, vol. i. p. 241; and the loss of weight is determined at the close of the effervescence.

FIG. 7. Mr. Leslie's differential thermometer described, vol. i. p. 80.

FIG. 8. (a) An air thermometer, for ascertaining the temperature of liquids. It consists of a bottle, partly filled with any coloured liquid, and partly with air, a glass tube of small bore, open at both ends, being either cemented or hermetically sealed into the bottle, so that its lower extremity may nearly touch the bottom of the bottle. The expansion of the included air, on the application of heat, drives the coloured liquid up the tube, and to an extent which may be measured by the application of a scale. The fig. b is another variety of the same instrument, described vol. i. p. 80.

FIG. 9. The original air thermometer of Sanctorio; see vol. i, p. 80.

FIG. 10. A bent funnel for introducing liquids into retorts, without soiling their necks.

FIG. 11. An adopter. The wider end admits the neck of a retort; and the narrower is passed into the mouth of a receiver.

FIG. 12. A section of an evaporating dish of Wedgwood's ware. Under this figure is a representation, without any number attached to it, of a small prong with a wooden handle, for holding an evaporating glass over a lamp.

FIG. 13. (a) A tubulated retort luted to (b) a quilled receiver the pipe of which enters the neck of a bottle (c) supported by a block of wood.

FIG. 14. Different forms of jars for precipitations, with lips conveniently decanting the fluid from the precipitate.

FIG. 15. A tube blown in the middle into a ball, for dropping liquids. The ball is filled by the action of the mouth applied to the upper orifice, while the lower one is immersed in the liquid. To the former the finger is then applied; and, on cautiously removing it, the liquid is expelled in drops.

FIG. 16. A bottle for ascertaining the specific gravity of liquids. When filled up to a mark in the neck, with distilled water of a given temperature, it should hold 1000, 2000, or any even number of grains. The quantity, which it is found to contain, of any other liquid of the same temperature, shows the specific gravity of the latter. For example, if it hold 1000 grains of water, and 1850 of sulphuric acid, the specific gravity of the latter is to that of water as 1850 to 1000.

PLATE II.

FIG. 17. An apparatus for procuring gases, without the possibility of their escaping into the room during the process, a circumstance which is of considerable importance, when the gas has an unpleasant smell or deleterious properties. Suppose that sulphureted hydrogen gas is to be obtained from sulphuret of iron and diluted sulphuric acid. The sulphuret of iron, in coarse powder, is put into the body of the gas bottle c, with a proper quantity of water. The acid