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pearance of silver. It is exceedingly malleable, and is softer than any of the common metallic substances. It is a good conductor of electricity and heat, and small globules of it inflame by the voltaic electrical spark, and burn with bright explosions: its specific gravity is something more than 93. It becomes fluid at about 180° of Fahrenheit; but the exact degree of heat at which it becomes volatile, has not been ascertained.

The chemical phenomena, produced by the basis of soda, are in many respects analogous to those produced by the basis of potash: when exposed to the atmosphere, it immediately tarnishes, and by degrees becomes covered with a white crust, which deliquesces much more slowly than the substance that forms on the basis of potash, and which proves to be pure soda. The basis combines slowly with oxygen, and without luminous appearance, at all common temperatures: and when heated, this combination becomes more rapid; but no light is emitted, till it has acquired a temperature nearly that of ignition. In oxygen gas, it burns with a white light: in oxymuriatic acid gas, it burns vividly with a bright red light; saline matter is formed, which proves to be muriate of soda. When thrown upon wa

ter, it produces a violent effervescence, with a loud hissing noise; it combines with the oxygen of the water to form soda, which is dissolved, and its hydrogen is disengaged.

The basis of soda acts upon alcohol and ether in the sale manner with the basis of potash. The water contained in them is decomposed; soda is rapidly formed, and hydrogen is disengaged. When thrown upon the strong acids, it acts upon them with great energy; if the nitrous acid is employed, a vivid inflammation is produced; with muriatic and sulphuric acids there is much heat generated, but no light.

It combines with sulphur in close vessels, filled with the vapour of naphtha, with great vividness, with light, heat, and afterwards with explosion from the vaporization of a portion of sulphur, and the disengagement of sulphuretted hydrogen gas. The phosphuret has the appearance of lead, and forms phos

phate of soda, by exposure to the air, or by combustion. The basis of soda, in the quantity of one fortieth part, renders mercury a fixed solid, of the colour of silver, and the combination is attended with a considerable degree of heat. It makes an alloy with tin, without changing its colour; and it acts upon lead and gold when heated.

From some very accurate experiments, Mr. Davy has found that 100 parts of potash consist of 86.1 of the basis, and 13.9 of oxygen and in 100 parts of soda, there will be 80 parts of the basis, and 20 of oxygen.

To the question, whether the basis of potash and soda should be called metals, Mr. Davy says, that the greater number of philosophical persons answer in the affirmative. They agree with metals in opacity, lustre, malleability, conducting powers as to heat and electricity, and in their qualities of chemical combination: their low specific gravity does not appear a sufficient reason for making them a new class; for among the metals themselves, there are remarkable differences in this respect; platina being nearly four times as heavy as tellurium; and in the philosophical division of the classes of bodies, the analogy between the greater number of properties must always be the foundation of arrangement; hence the basis of the alkalies are denominated Potassium and Sodaum.

In reference to his own discoveries, Mr. Davy observes, that, "In the common processes of nature, all the products of living beings may be easily conceived to be elicited from known combinations of matter. The compounds of iron, of the alkalies, and earths, with mineral acids, generally abound in soils. From the decomposition of basaltic, porphyritic, and granitic rocks, there is a constant supply of earthy, alkaline, and ferruginous materials to the surface of the earth. In the sap of all plants that have been examined, certain neutro-saline compounds, containing potash, or soda, or iron, have been found. From plants they may be supplied to animals. And the chemical tendency of organization seems to be rather to combine substances into

more complicated and diversified arrangements, than to reduce them to simple elements."

From the fixed alkalies, the Professor proceeded to the earths, which are non-conductors of electricity. The alkalies become conducting substances by fusion: the infusible nature of the earths rendered it impossible to operate upon them in this state: the strong affinity of their bases for oxygen would not admit of their bodies being acted upon by solution in water; and the only methods that proved successful, were those by which they were operated upon by electricity in some of their combinations, or of combining them at the moment of their decomposition by electricity, in metallic alloys, so as to obtain evidences of their nature and properties.

On this plan Mr. Davy undertook a series of experiments on Barytes, Strontites, and Lime, employing upon them the same methods as he had used in the decomposition of the fixed alkalies. Gas was, in each case, copiously evolved, which was inflammable; and the earths, where in contact with the negative metallic wires, became dark-coloured, and exhibited small points, having a metallic lustre, which, when exposed to air, gradually became white: they became white likewise when plunged under water; and when examined by a magnifier, a greenish powder seemed to separate from them.

He then made mixtures of dry potash in excess, and dry barytes, lime, strontites, and magnesia, brought them into fusion, and acted upon them in the voltaic circuit, as he had done in obtaining the metals of the alkalies. He hoped, by this means, that the potassium, and the metals of the earths, might be deoxygenated at the same time, and enter into combination in alloy. Metallic substances appeared less fusible than potassium, which burnt the instant after they had formed, and which, by burning, produced a mixture of potash, and the earth employed. He had found, that when a mixture of potash and the oxides of mercury, tin, or lead, was electrified in the voltaic circuit, the decomposition was very rapid, and an amalgam, or an alloy of

potassium, was obtained.

He tried the same on a mixture of

two parts of barytes and one part of oxide of silver, very slightly moistened when it was electrified by iron wires, an effervescence took place at both points of contact, and a minute quantity of a substance, possessing the whiteness of silver, formed at the negative point.

A mixture of barytes and red oxide of mercury, in the same proportions, was electrified in the same manner. A small mass of solid amalgam adhered to the negative wire, which evidently contained a substance that produced barytes by exposure to air, with the absorption of oxygen; and which occasioned the evolution of hydrogen from water, leaving pure mercury, and producing a solution of barytes. Mixtures of lime, strontites, magnesia, and red oxide of mercury, treated in the same manner, gave similar amalgams, from which the alkaline earths were regenerated by the action of air and water.

While Mr. Davy was pursuing these experiments, he heard that Professor Berzelius, and Dr. Pontin, of Stockholm, had succeeded in decomposing barytes and lime, by negatively electrifying mercury in contact with them; and that in this way they had obtained amalgams of the metals of these earths. Mr. Davy repeated the experiments with a battery of 500, and obtained the most perfect success. The mercury gradually became less fluid, and after a few minutes, was covered with a white film of barytes; and when the amalgam was thrown into water, hydrogen was disengaged, the mercury remained free, and a solution of barytes was formed. The result with lime was precisely analogous, so also was that with strontites; with magnesia it was with more difficulty obtained. All these amalgams may be preserved a considerable period under naphtha; but in a length of time they become covered with a white crust. When exposed to air, a very few minutes only were required for the oxygenation of the bases of the earths.

In several cases, Mr. Davy exposed the amalgams of the metals of the earths, containing only a very small quantity of

mercury, to the air, on a delicate balance; and he always found that, during the conversion of metal into earth, there was a considerable increase of weight. He also found that, when the metals of the earths were burned in a small quantity of air, they absorbed oxygen, gained weight, and were in a highly caustic or unslaked state; for they produced strong heat by the contact of water, and did not effervesce during their solution in acids. Hence it is inferred, that the evidence for the composition of the alkaline earths is of the same kind as that for the composition of the common metallic oxides; and the principles of their decomposition are precisely similar; the inflammable matters in all cases, separating at the negative surface in the Voltaic circuit, and the oxygen at the positive surface. The professor denominates the metals obtained from the alkaline earths, Barium, Strontium, Calcium, and Magnium.

The professor next tried a number of experiments on the other earths, which are not alkaline; and from the general tenor of these results, and the comparison between the different series of experiments, there seems very great reason to conclude that alumine, zircon, glucine, and silex, are, like the alkaline earths, metallic oxides. He admits, however, that the evidences of decomposition and composition are not of the same strict nature as those that belong to the fixed alkalies, and alkaline earths; for it is possible that in the experiments, in which silex, alumine, and zircon appeared to separate during the oxidation of potassium and sodaum, their bases might not actually have been in combination with them, but the earths themselves, in union with the metals of the alkalies, or in mere mechanical mixture.

The strong attraction of potassium, sodaum, and the metals of the alkaline earths for oxygen, led Mr. Davy to examine if their deoxydating powers could not be made to produce the effect of the amalgamation of ammonia, independently of the agency of electricity; and he found that, when mercury, united/ to a small quantity of potassium, soḍaum, barium, or calcium, was made to act upon moistened muriate of ammonia, the amalVOL. 1.

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