is very soluble in hidrogen; but, under common circumstances, hidrogen does not seem to be absorbable by potassium. When potassium is heated in hidrogen in a fint glass retort, of even for a great length of time in a green glass returt, there is an ab- Hidrogen absorption of the gas; but this is independent of the presence of pot- sorbed by the assium, and is owing to the action of the metallic oxides in the glass oxides in the glass. upon the hidrogen. If a solid compound of hidrogen and potassium could be forined, we might expect its existence in the experiment with the gun barrel, in which potassium is exposed to hidrogen at almost every temperature; but the metal formed in this process, when proper precautions are faken to exclude carbonaceous matters, is uniform in its properties, and generates, for equal quantities, equal proportions of hidrogen by the action of water. The general phenomena of this operation show indeed, that the solution of potassium in hidrogen is-intimately connected with the general principle of the decomposition, and confirm my first idea of the action of the two bodies. Hidrogen dissolves a large quantity of potassium by heat, but the greater portion is precipitated on cooling. The attractions which de termine the chemical change seem to be that of iron for oxigen, of iron for potassium, and of hidrogen for potassium; and in experiments, in which a very intense heat is used for the production of potassium by iron, I have often found, that the gas which comes over, though it has passed through a tube cooled by ice, inflames spontaneously in the atmosphere, and burns with a most brilliant light, which is purple at the edges, and throws off a dense vapour containing potash. Sodium appears to be almost insoluble in hidrogen, and this seems Sodium nearly to be one reason why it cannot be obtained, except in very minute insoluble in quantities, in the experiment with the gun barrel. hidrogen. Sodium, though scarcely capable of being dissolved in hidrogen alone, seems to be soluble in the compound of hidrogen aud potassium. By exposing mixtures of potash and soda to iguited iron I have ob tained some very curious alloys; which, whether the potassium or the Curious alloys. sodium was in excess, were fluid at common temperatures. The compound containing an excess of potassium was even light than potassium (probably from its fluidity). All these alloys were in the highest degree inflammable. When a globule of the fluid alloy was touched by a globule of mercury, they combined with a heat that singed the paper upon which the experiment was made, and formed, when cool, a solid so hard, as not to be cut by a knife. (To be continued in our next.) VOL. XXII.-AUGUST, 1809. On Soda and muriatic acid produced from water by gal vanism. Mr. Davy's experiments II. On the Production of an Acid and an Alkali from pure SIR, To Mr. NICHOLSON. IT is now a long time since I had the pleasure of com Ꭲ municating any thing to your valuable periodical work, although I was under a promise to send you something decisive on the subject of the production of soda and muriatic acid, from pure water, by galvanism. I should not at present have ventured to have offered any thing on this subject, knowing, that the tide of opinion must have gone with the decisions of Mr. Davy, who has said, that the acid and alkali are produced from foreign matter in the water, or in the vessels employed; had not the truth and consequent reasonings of my experiments been strongly supported by many recent facts, brought forward by Mr. D. himself. All the experiments, in which Mr. Davy has produced the apparent base of an alkali, an earth, or even acid, are nothing more than degrees of the same process, by which the alkali is produced when pure water is exposed to the galvanic influence; and it is equally evident, that all the made on ox- bodies he has, in these experiments, operated upon, are oxides of hidrogen. I have not the least hesitation in saying, that the aeid and alkali can be produced, from pure water; in such abundance as not to admit a doubt of their being derived from the water, or the apparatus. The im portance of the electrical agency in chemical processes appears principally to consist in hidrogen and oxigen being! furnishod in their nascent and pure form; for it will be recollected, that in all experiments, in which the alkalis and the earths have appeared to be decomposed, the presence. of water has always been essential to the changes produced. ides of hidro. gen. Acid and alkali produced in abundance. Electrical agency in chemical pro cesses. Water with oxigen forms acids; with It is therefore probable, that water with different portions of exigen forms acid products; and with hidrogen, and metals. alkalis, earths, and metals. In the experiment, where pure hidrogen, alwater is exposed to the galranic influence, separated into kalis, earths, two portions by some moist conductor, the oxigen is presented in its nascent form, and an acid is produced, from that substance combining with the water; and at the point where the hidrogen is presented, an alkali is formed, by a similar fixation of hidrogen. In the pretended decomposition of potash, the alkali combines with an extra dose of hidrogen, forming the metallic globulus. And when a metal was said to be produced from ammonia, forming an alloy with potassium remarkable for its little specific gravity, the effect could only be attributed to that metal combining with a still greater portion of hidrogen. and consistent. ter. The electrical doctrine of Mr. Davy is so replete with Mr. Davy's truth and consistency, that I am every day more pleased doctrine true with it. It would seem, that we have only two kinds of Only two kinds simple matter; one something like oxigen, possessing the of simple mat effects of negative electricity in the greatest degree; the other a general inflainmable substance of the nature of hidrogen, endowed with positive electricity: that each of these bodies has a constant repulsion between their homogeneous particles, and hence is permanently elastic; that equal portions of these bodies combined would constitute a body of the greatest possible density, from the attraction being at a maximum: and that, as one of them predominates, the attraction becomes less. Hence it appears, that No solid a the particles of simple matter are repellent of each other, simple body. and that no solid body can be considered a simple body. A friend of mine intends soon to favour you with a more extensive essay on this subject. If you think the above observations will at all interest the readers of your work, their insertion in your next will much oblige, Sir, Your humble servant, Derby, June 23, CHARLES SYLVESTER. 1809. This letter came too late for insertion last month. It seems proper to notice, that Mr. Davy states the decompo $ 2 sition sition of potash &c., where no water was present. With res W. N. Decomposi tion of boracic ed. III. Account of the Decomposition and Recomposition of Boracic ON N the 21st of June last we announced in a note read at acid announce the Institute, and we published in the Bulletin de la So ciété Philomatique for July, that by treating the fluoric and boracic acids with the metal of potash we obtained results, which could only be explained by admitting these acids to be compounds of a combustible substance and oxigen. However, as we had not recomposed them, we added, that we did not give this composition as completely demonstrated. Since that time we have continued and varied our researches, and are now able to assert, that the composition of the boracic acid is no longer problematical. In fact, we can decompose this acid and recompose it at pleasure. Method in which it was To decompose it, we put equal parts of the metal and decomposed. very pure and well vitrified boracic acid into a copper tube, to which a curved glass tube is fitted. The tube of copper is placed in a small furnace, and the extremity of the glass tube in a jar filled with mercury. The apparatus being thus arranged, the copper tube is heated gradually, till it is slightly red hot. In this state it is kept for some minutes. The operation being then finished, it is cooled, and the Journal de Physique for November, 1808, Vol LXVII, p. 393. Mr. Davy's experiments on the boracic acid will appear in the course of the paper, of which the commencement is given in our present number. See also Journal, Vol. XX, p. 331, and Vol. XXI, p. 375. · matters matter taken out. The following are the phenomena ob served in this experiment. observed in the experiment. When the temperature is about 150° [302° F.], the mix- Phenomena ture on a sudden grows highly red, as may be seen in a striking manner by using a glass tube. There is even so much heat produced, that the glass tube partly melts, and sometimes breaks, and the air of the vessels is almost al ways expelled with force. From the beginning of the experiment to the end, nothing is disengaged but atmos spheric air, and a few bubbles of hidrogen gas, not answering to a fiftieth part of what the metal employed would give out by means of water, All the metal constantly dis appears in decomposing part of the boracic acid; and the two substances are converted by their reciprocal action into an olive gray matter, which is a mixture of potash and the radical of the boracic acid. This mixture is extracted from the tube by pouring in water, and heating it gently; and the boracic radical is separated by repeated washing with warm or cold water, Before this washing it is advisable to saturate the alkali contained in the mixture with muriatic acid for it appears, that the boracic radical can become oxided, and then dissolve in the alkali, to which it gives a yery deep colour. What does not dissolve is the radical itself, which possesses the following properties. It is of a greenish brown colour, fixed, and insoluble in Properties af water. It has no taste; and no action on infusion of litmus the base of boracic acid, or sirup of violets. Mixed with oximurate of potash, or nitrate of potash, and projected into a red hot crucible, a vivid combustion ensues, one of the products of which is the boracic acid. When it is treated with nitric acid, a great effervescence takes place, even in the cold and when the fluid is evaporated, a great deal of the boracic acid is ob tained. But of all the phenomena produced by the bora cic radical in its contact with different substances, the most curious and most important are those it exhibits with oxigen. On projecting 3 decig. [4 grs.] of boracic radical into a This base, silver crucible scarcely at a dull red heat; and covering the heated in oxi crucible with a jar holding about a litre [a wine quart], fill- gen gas, ed wish oxigen gas, and placed over mercury; a combus |