PROCEEDINGS OF LEARNED SOCIETIES.

ROYAL SOCIETY OF LONDON.

AVING in our last given an account

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 phosphate of soda, by ex

Hof Mr. Davy's discoveries with se gard to potash, we shall proceed, as we proposed, to consider the properties and nature of the basis of Soda. The basis or metallic substance obtained by decomposition, is a solid at the common temperature. It is white, opaque, and if ex-posure to the air, or by combustion. amined under a film of naphtha, has the The basis of soda in the quantity of Justre and general appearance of silver. part, renders mercury a fixed solid of the It is exceedingly malicable, and is softer colour of silver, and the combination is than any of the common metallic sub- attended with a considerable degree of stances. It is a good conductor of elec- heat. It makes an alloy with tin, withtricity and heat, and small globules of it out changing its colour, and it acts upon inflame by the voltaic electrical spark, lead and gold when heated. 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 pare soda. The basis comkines 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 water, 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 same manner with the basis of pot-ash. 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.

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 bases 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 bases 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 neutrosaline compounds, containing potash, or soda, or iron, have been found. From plants, they may be supplied to animals. And the chemical tendency of organization

organisation 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 nonconductors of electricity. The alkalies become conducting substances by fusion: the infusible nature of the earths, rendeird 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 f combining them at the moment of their decomposition by electricity, in metallic alloys, so as to obtain evidences of their nature and proper

ties.

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 green ish powder seemed to separate from them.

He then made mixtures of dry pot-ash in excess, and dry barytes, lime, strontites, and magnesia, brought thent iuto fusion, and acted upon them in the voltaic circuit, as he had done in obtaining the metals of the alkalies. He boped, 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 pot-ash, and the earth employed. He had found, that when a mixture of pot-ash, 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 saine 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 me tals 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 be come 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 balauce, 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 prodaced strong heat by the contact of water, and did not effervesce during their solu tion 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

colour, lustre, opacity, and conducting powers, remaining unimpaired. It is scarcely possible to conceive, that a substance which forms with mercury so perfect an amalgam should not be metallic in its own nature, hence it may be denomi

decomposition are precisely similar; the
inflaminable matters in all cases, separa-
ting at the negative surface in the Voltaic
eircuit, and the oxygen at the positive sur-
face. The professor denominates the
metals obtained from the alkaline earths,
barium, strontium, calcium, and mag-nated ammoniun."
nium.

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, sodaum, barium, or calcium, was made to act upon moistened muriate of ammonia, the amalgam rapidly increased to six or seven times its volume, and the compound seemed to contain much more ammoniacal basis, than that procured by electrical powers,

The amalgam from ammonia, when formed at the temperature of 700 or 80°, is a soft solid, of the consistence of butter; at the freezing temperature it be comes firmer and a crystallized mass, and its specific gravity is below 3. When exposed to air, it soon becomes covered with a white crust, which proves to be carbonate of ammonia.

"The more," says Mr. Davy, "the properties of the amalgam obtained from ammonia, are considered, the more extraordinary do they appear. Mercury, by combination with about the 12 part of its weight of new matter, is reudered solid, yet it has the specific gravity diminished from 13.5 to less than S, and it retains all its metallic characters; its

1

From the preceding facts, the following questions have occurred: on what do the metallic properties of ammonium depend? Are hydrogen and nitrogen both metals in the aeriform state, at the usual temperature of the atmosphere, bodies of the same character as zinc and quicksilver would be in the heat of igni tion? Or are these gases in their common form, oxides, which? become metallized by deoxydation? Or are they simple bodies, not metallic in their own nature, but capable of composing a metal in their deoxygenated, and an alkali in their oxygenated, state?

Assuming the existence of hydrogen, in the amalgam of ammonium, its presence in one metallic compound evidently leads to the suspicion of its combination in others. And in the electrical powers of the different species of matter, there are circumstances which extend the idea to combustible substances in general. Oxygen is the only body which can be supposed elementary, attracted by the positive surface in the electrical circuit; and all compound bodies, the nature of which is known that are attracted by this surface, contain a considerable proportion of oxygen. Hydrogen is the only matter attracted by the negative surface, which can be considered as acting the op posite part to oxygen; "may not then," says the professor," the different inflammable bodies, supposed to be simple, con tain this as a cominon element ?"

Should future experiments prove the truth of this hypothesis, still the alkalies, the earths, and the metallic oxides, will belong to the same class of bodies. From platina, to potassium, there is a regular order of gradation as to their physical and chemical properties, and this would probably extend to ammonium, could it be obtained in the fixed form. Platina and gold, in specific gravity, degree of oxydability, and other qualities, differ more from arsenic, iron, and tin, than these last do from barium and strontium. The phenomena of combustion of all oxidable metals, are precisely analogous. In the same manner as arsenic forms an acid, by burning in air, potassium forms an alkali, and calcium an earth; in a manner similar to that in which osmium forms a vola

tile,