! That two annular excoriations on two of the branches. In the spring of the year 10, (1802,) I pruned one of the branches on which I had made the annular excoriation and one of the others, leaving the new wood on the two remaining branches. I observed: 1. That the branch submitted to the operation, and pruned had produced very few shoots, and that these were both short and small. The branch not submitted to the operation and pruned, had produced a great number of vigorous shoots. 2. The young shoots, left on the other branch submitted to the operation, had increased very little in their dimensions; while those of the branch on which I had not operated had grown very much. 3. The two branches, not submitted to the operation, produced no fruit; of the two other branches, that which bad been pruned bore fewer apples than that not pruned, the young shoots of which were covered with fruit. Experiment IV. In the year 9, (1801,) I made an annular excoriation on a branch of a pear-tree trained as an espalier; but did not meddle with the other branch forming the other half of the tree. The same year the increase of fruit was considerable. The 10th Thermidor, year 10, (1802,) from the part submitted to the operation I gathered pears perfectly ripe, weighing four ounces each, while those from the other half of the tree weighed no more than one ounce and a half. On the former, the number of pears that ripened was 81; the latter produced only 9 small ones, which dropped off before they arrived at perfect maturity. It is necessary to remark, that there were as many blossoms on one side of the tree as on the other; but that those on the side where the excoriation was made were all fruitful, while almost all those on the other side fell off. I think it superfluous to weary the reader with a greater number of facts, as the above will suffice to demonstrate the efficacy of the process here recommended. Process for extracting Soda from Minerals. From KLAPROTHS'S ANALYSIS of MINERAL SUBSTANCES. THE analysis of sonorous porphyry (klingstein) forms the subject of a memoir read by M. Klaproth to the Academy of Sciences of Berlin the 25th June 1801. The author begins by observing how little attention has been paid to the analysis of the most common mineral substances by those chemists who have devoted their labours to that kind of research, though the knowledge of their composition is highly important to the science of Natural History. He then enters into some interesting details relative to the history of the mineral, of which he is about to present the analysis; according to which it appears that Ferber and De Born considered it a variety, sometimes of argillaceous, sometimes of micaceous schistus; that M. De Charpentier was the first mineralogist who imagined that it was a distinct substance, to which he gave the name of corneous schistus (horn schiefer); that M. Werner, having afterwards observed it with attention, discovered that its structure resembled porphyry, coutaining in its composition crystals of feldspath and hornblend, and that he gave it the name of porphyric schistus, because it might be separated into lamina. M. Klaproth thinks thinks this denomination should be changed; he therefore gives it a name taken from that of the mass, which constitutes this porphyric rock; he calls it klingstein porphir, that is, porphyry with a basis of sonorous stone. The specimen of the klingstein which M. Klaproth employed for this analysis, was taken from the mountain of Millischau, in Bohemia. When ignited for half an hour, it lost three per cent of its weight; its colour, originally of a greenish-grey, became a whitish-grey. In a porcelain-furnace it was fused into a thick vitreous matter. The author then enters into the details of the analysis; the results of which are: The specific gravity was equal to 2,575. This analysis led M. Klaproth to his ingenious manner of extracting the soda existing as a component part in certain mineral substances. The following is the process by which he effects that purpose. "One hundred grains of very pure klingstein were pounded with 400 grains of nitrate of barytes; the mixture being put into a porcelain crucible, was at first exposed to a moderate fire, which was gradually raised to a red heat; when the bubbling ceased I increased the degree of heat; but upon uncovering the crucible I ob served some thick whitish vapours rising from amidst the viscous matter, and apprehensive that the soda was escaping in a volatile form, I slackened the fire. "The matter when cold was of a light blue colour, porous like a spunge, and very friable; when dissolved in muriatic acid diluted with a large quantity of water, I obtained a solution of a yellow colour, and perfectly limpid; this I put into a porcelain retort, upon a sand-bath, and gradually added so much sulphuric acid that there was sufficient not only to precipitate the barytes, in the form of sulphate, but likewise to predominate perceptibly, after having entirely disengaged the muriatic acid. "The evaporation was continued to a moderate degree of dryness; the residue was diluted in water; the sulphate of barytes and silex which remained at the bottom were separated by the filtre; and the solution, which was limpid, was saturated and precipitated with ammoniac. The sediment that was formed was again separated by the filtre, and the solution evaporated to dryness. The saline residue, thus obtained, was put into a porcelain crucible, and exposed to a moderate degree of heat till all the sulphate was evaporated. The fixed part, that which remained in the crucible, was diluted with water, and afterwards crystallized; the crystals were pure sulphate of soda. This salt was again dissolved, and afterwards decomposed by acetite of barytes; a sulphate of barytes was precipitated, separated by the filtre, and the solution evaporated to dryness. The acetite of soda was exposed to a red heat in a crucible of platina; the coaly residue dissolved in water and filtered, furnished a ley, clear and colourless, from which were extracted, by eva poration, 14 grains of carbonate of soda, yielding 8% grains of pure soda. Dissolved in nitric acid, and left to VOL. IV.-SECOND SERIES. Q q crys crystallize, it formed crystals of nitrate of soda of a rhom boidal form. "The quantity of soda contained in the klingstein may be regarded as rather greater than what I have here stated; because, besides the loss inevitable in the operations through which any substance that is analysed must necessarily pass, the thick filamentous vapours that escaped when I uncovered the crucible in which I ignited the mineral with the barytes, appeared to me to proceed from a volatilization of the soda." M. Klaproth concludes his memoir with remarking the importance of the discovery of soda in a mineral substance, of which whole chains of mountains are com, posed: this alkaline substance is equal to one-twelfth in the composition of the klingstein. He observes that the mountain of Millischau alone, which is nearly a perfect cone, above 800 metres in height, would afford a supply of soda equal to the consumption of all Europe during a long series of years, if a convenient method of extracting it could be discovered. Notice on several Processes, but little known, employed for gilding and silvering Metals. From the ANNALES DES ARTS ET MANUFACTURES. THE lustre of gold is pleasing to every eye; but this precious substance is so rare, that the arts have been obliged to resort to various methods of multiplying it in appearance, by slightly covering the most common metals with this costly material. Such is the origin of gilding. For the purpose of gilding, the artizan either covers the metal directly with a leaf of gold, or he forms an amalgama |