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that state in any quantity, or without great difficulty, its characters can only be ascertained by examining its combinations with different bases. Some of the principal of these will be here given. The hyposulphites are easily soluble in water, and their solutions have either an intensely bitter, or intensely sweet taste. When heated to a degree below redness, they are decomposed; and while sulphur separates, a sulphite, or in some cases a sulphuret of the base remains. The action of nitric acid, or a stream of chlorine passed through their solutions, converts them into sulphates. The hyposulphites and their solutions are decomposed by all other acids, except the carbonic, especially when heated with them. They precipitate lead from its solutions in white powder, which is hyposulphate of lead. Oxi-nitrate of silver, and nitrate of mercury, dropped into a dilute solution of any hyposulphite, precipitate their respective metals in the state of sulphurets. Nitrate of bismuth when heated, undergoes the same change; while solutions of manganese, iron, zinc, copper, tin, suffer no such precipitation. But one of the most remarkable properties of the hyposulphites is that which their solutions possess of dissolving muriate of silver, and retaining it in considerable quantity in permanent solution.

We shall now proceed to give a condensed description of the salts which Mr Herschell succeeded in forming, beginning with that of lime, which is the most readily obtained in a state of purity.

Hyposulphite of lime may be formed by exposing the hydroguretted sulphuret of that alkali in a flat vessel, for ten or twelve days to the air, or by boiling, for a considerable time, the sulphite of lime with sul

phur in a large quantity of water. This salt usually crystallizes into irregular six-sided prisms, whose faces are inclined to each other at angles of 11° 39', 110° 45', and 107° 36'. They refract doubly, and dissolve readily in water: at the temperature of 37°, that liquid dissolves nearly its own weight of them, and during the solution the thermometer sinks to 31°. At 50°, the specific gravity of a saturated solution is 1.300; and when the temperature is 60°, and the specific gravity 1.114371, the solution contains 0.2081 of its own weight. These crystals are not altered by exposure to air, unless it be very dry. From Mr Herschell's experiments, this salt appears to be composed of

2 atoms hyposulphurous acid, 6.000 1 atom lime, 3.625

6 atoms water, ................................................................. 6.750

16.375

Hyposulphite of potash is readily prepared, either by precipitating that of lime by the carbonated alkali, or immediately decomposing hydrosulphuret or hydroguretted sulphuret of potash by sulphurous acid, and evaporating to a pellicle. It then crystallizes into a confused mass of spicule. It has a penetrating taste like nitre, succeeded by bitterness, and deliquesces readily when exposed to the air. When heated, it dries down to a white mass, then takes fire, and burns like a piece of tinder.

Hyposulphite of soda may be formed in precisely the same manner. On cooling, it crystallizes in silky tufts radiating from centres, which at length extend through the whole liquid, and become almost solid. Its taste is intensely bitter and nauseous. When heated, it first undergoes the watery fusion, then dries into a white mass, and at length takes

fire, burning with a vivid conflagration and bright yellow flame.

Hyposulphite of ammonia is not easily procured in regular crystals. Its taste is excessively pungent, and succeeded by a disgusting bitterness. When heated, it burns with a weak flame, and evaporates entirely.

Hyposulphite of barytes is a white brilliant scaly powder, which is soluble in dilute muriatic acid, but not in 2000 times its weight of water. When heated on a platina foil, it was thrown into a singular agitation, and seemed enveloped by a kind of fog caused by its own dust, thrown up in an infinite number of minute explosions. According to Mr Herschell's analysis, it is a compound of two atoms acid plus one atom barytes.

Hyposulphite of strontian crystallizes in flat rhombs, having the plane angles of their more extended surfaces, about 64° 45′ and 115° 15′; but their solid form is that of an oblique parallelopiped, whose sides are inclined to each other at angles of about 76° 30′, 96° 45', and 97° 13'. It is doubly refractive, and soluble in about four times its weight of water at the temperature of 45°, while it dissolves in 1.75 times its weight of boiling water. Its taste is excessively bitter. It is insoluble in alcohol; but readily dissolves muriate of silver, while alcohol precipitates the solution in the state of a sweet syrup. Hyposulphite of magnesia is easily formed by boiling a solution of sulphite of magnesia with flowers of sulphur. It readily crystallizes, is intensely bitter, dissolves easily in water, but is apparently not deliquescent. When laid on a hot iron, it burns with a weak blue flame; but is incapable per se of maintaining the

combustion: when heated in the flame of a blow-pipe, it swells into a fungous mass, by the escape of sulphur, as borax does by that of water.

Passing over the hyposulphites of alumina and iron, the former of which Mr Herschell endeavoured to insulate, in various ways, without success, we come to the hyposulphite of copper, which may be obtained by digesting hyposulphite of lime on carbonate of copper, or by mixing sulphate of copper with hyposulphites of lime, potash, &c. It is colourless, and has an intensely sweet taste, without any metallic flavour. It is not decomposed by ammonia, nor turned blue by an excess of that alkali, provided the air be excluded. The copper in this salt is, therefore, in the state of protoxide.

Hyposulphite of lead is a white mealy powder, obtained by pouring nitrate of lead into a neutral hyposulphite, and when held long in the mouth leaves an impression of sweetness. It requires for solution not less than 3266 times its weight of water. When heated even below 212° it turns black; and when the temperature is raised, takes fire, and, becoming red hot, burns with a weak flame. If it be now removed from the fire, the ignition and combustion may be maintained for any length of time, by cautiously adding small quantities of the substance. cording to the analysis of Mr Herschell, this salt is composed of two atoms acid plus one atom protoxide of lead.

Ac

Hyposulphite of silver may be form. ed by adding nitrate of silver to a diluted solution of any hyposulphite. It has an exceedingly sweet taste *. In a short time it is decomposed, and

The sudden production of intense sweetness, by mixing two such disgustingly bitter liquids as nitrate of silver and byposulphite of soda is very striking, and proves how little we know of the manner in which bodies affect the organs of taste.

VOL. XII. PART I.

Y

sulphuret of silver precipitated. Mr Herschell has shown that the hyposulphite of silver has the property of combining with several of the other hyposulphites, and forming double salts, which have some permanency. Of these he has described the following:

Hyposulphite of potash and silver.

of soda and silver.
of ammonia and silver.
of lime and silver.
of strontian and silver.
of lead and silver.

Mr Herschell's experiments to procure the hyposulphite of mercury do not appear to have led to very sa tisfactory results. It seems to follow from them, however, that hyposulphurous acid is capable of combining with the peroxide, but not with the protoxide of mercury. His trials also to procure hyposulphurous acid in a separate state, though not completely successful, seem not entirely to preclude the hope of here. after accomplishing it.

Hyposulphuric acid has been only recently discovered by Gay-Lussac and Welter, who obtained it by passing a current of sulphurous gas through water in which the black oxide of manganese was suspended. Sulphates and hyposulphates of manganese were formed. These salts were decomposed by means of carbonate of barytes, and nothing remained but hyposulphate of barytes, which was crystallized, redissolved in water, and the barytes precipitated by the cautious addition of sulphuric acid. From these experiments, it appears that hyposulphuric acid is a compound of one atom of sulphuric, plus one atom of sulphurous acid. It may be concentrated to a certain point; but if the concentration be farther urged, sul

phurous acid escapes, and nothing remains but sulphuric acid. All the salts formed with bases by this remarkable acid appear to be soluble.

Some curious experiments, formerly made by Sertürner, on the action of sulphuric acid on alcohol, have been repeated and confirmed by M. Vogel of Munich, and especially by M. Gay-Lussac, who prepared sulphovinate of barytes in a state of purity, and subjected the acid to analysis. It crystallizes in fine rhomboidal prisms, terminated by foursided pyramids, the faces of which correspond with those of the prism. They are transparent, and do not alter in the open air, but become opaque when kept under an exhausted receiver along with sulphuric acid. Of this salt, when calcined, 100 parts dried in the air lost 45.07 parts, and furnished 54.93 parts of sulphate of barytes. The same quantity of salt, calcined with chlorate and carbonate of potash, and afterwards precipitated by muriate of barytes, yielded 111.47 parts of sulphate of barytes, or nearly double what was obtained in the first experiment. Thus, it appears, that the acid possesses exactly the constituents and the capacity of saturation of hyposulphuric acid, and that the vegetable matter which it holds in combination produces no alteration in these particulars. This curious subject requires much fuller investigation.

Four new alkaline substances have been discovered and described by the French chemists, to which they have given the names of morphine, strychnine, brucine, delphine, and picrotoxine. They have been found in the seeds, bark, or fruit of vegetables.

MINERAL WATERS.

Analyses of certain mineral waters, in different parts of the world, having appeared in the course of the

year in the Scientific Journals, it may be useful to collect and exhibit the results, in a few instances.

Of the water of the boiling spring in the harbour of Milto, Dr Thomson analysed a specimen about a year and a half ago, and found its specific gravity to be 1.0331. Its saline constituents, in 500 grains of this water, determined according to the method described in the "Annals of Philosophy," xiv. 27. are as follow: Common salt,........................20.924 Muriate of lime,..... Sulphate of soda,.........................................

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From which it follows, that the wa3.505 ters of this lake contain a greater 0.684 quantity of salt than any other mineral waters hitherto examined, 25.113 those of the Dead Sea excepted.

So that it contains about one half per cent. more of salt than sea-water does.

Mr Cooper examined a specimen of mineral water from the coast of Sussex between Newhaven and Rottingdean. It flows from a bed of chalk, and its temperature is uniformly 609 as it issues from the earth. Its specific gravity is 1.076; so that it is considerably heavier than the boiling spring in the island of Milto. It is slightly acidulous, and has the taste of iron. Mr Cooper detected the following substances in it: oxide of iron, alumina, muriatic acid, sulphuric acid, lime, carbonic acid, and soda.

We are indebted to Dr Marcet for an extensive set of experiments on sea water, collected from different seas, and from different depths of the same sea. Among others we find an analysis of the water of the Lake Ourmia, in Persia, situated at no great distance from the region of Mount Ararat. A small quantity of the water from this lake was sent by the late Mr Browne, the traveller, (of whose murder by Persian banditti, the reader will find an interesting and affecting account in the Travels of Sir Robert Ker Porter,) to

The specific gravity of the water of the Dead Sea, as determined by different chemists, varies a little. Klaproth found it 1.245; Gay-Lussac, 1.2283; and Dr Marcet, 1.211. But this difference is nothing compared to the discordance which prevails as to the chemical constituents of the water itself, and which shows how small progress has been made in the art of analysing mineral waters, and how little confidence can be reposed, on such a subject, even in the most accurate of our experimenters. It is therefore of the utmost consequence that the succes sive steps of every analysis, and the method employed in calculating the respective proportions of each constituent, should be carefully recorded. Attention to this will always render such experiments important; while those who merely set down the results of their experiments furnish us with no means of detecting their errors, and may rest assured that, hereafter, when the mode of analysis has become more perfect than at present, their conclusions will be of no value whatever. In confirmation of these remarks, and to point out more forcibly the necessity of what we recommend, we shall here give

the saline contents extracted from Sea, according to Marcet, Klap100 grains of water of the Dead roth, and Gay-Lussac.

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Klaproth's salts were only dried at the temperature of boiling water, which accounts for the much greater weight of his salts; but how are we to reconcile the great discordance between Marcet and Gay-Lussac in the weights of common salt and muriate of magnesia?

HEIGHT OF THE HIMALAYA MOUN

TAINS.

Geometrical measurements, by persons engaged in geographical surveys at the foot of this stupendous range, leave it no longer doubtful that the elevation of the mountains which divide India from Tartary surpasses considerably that of the Cordilleras of the Andes, formerly esteemed the highest points on the surface of the globe. In the 12th volume of the Asiatic Researches appeared a dissertation by H. T. Colebrooke, Esq., in which he examines the information then existing (in 1814) and supports the general conclusion already stated. Since that time the inquiry has been farther pursued, chiefly by Captain Webb, employed on a survey of the province of Kemaon, recently ceded to the British by the Nepalese. A list of the elevated peaks of the Himalaya mountains measured by him has appeared in various publications, and, as far as it goes, agrees with the ampler information contained in a memoir of his survey officially fur nished by him.

42.60

26.24

In this survey the accessible positions are determined with a sufficient degree of accuracy, from the resolution of triangles, of which all the angles were observed; but inaccessible places could not of course be so correctly determined, as but two angles could be taken. In the instance, therefore, of the more elevated peaks of the Himalaya, the distances were deduced from more than one triangle, and the mean of the different results taken. Hence the cases are not numerous where discrepancies appeared amounting to more than 100 fathoms in distance, or 100 feet in height. Being satisfied, then, that the distances might be relied on, Captain Webb proceeded to calcu late the heights of the several peaks observed by him in the snowy range. The largest set of observations was made at Calinath, an elevated station, of which the height geometrically determined is 6417 feet above the level of the sea, and barometri. cally 6388 feet above the level of Calcutta. Four of these peaks, and among them the highest of the whole, are distinctly visible at Casipur, and were then observed. This station is in the plain of Rohilkhund, and about 650 feet above the level of the sea. Every observation was repeated with the telescope reversed; and a mean of the angles as read off on both sides of zero assumed. It was also ascer tained that the telescope described true vertical angles, by bringing the intersection of the wires into contact

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