It is then slowly heated in a covered platinum crucible, till it is made red hot; the bydrogen combines with the oxygen, and the silicum will no longer burn in oxygen, while chlorine attacks it rapidly. The small quantity of silica produced may be dissolved by fluoric acid. If the silicum has not been strongly heated, as the acid dissolves it, a slow disengagement of hydrogen gas takes place. According to my experiments, silica must contain 0.52 of its weight of oxygen, Zirconium is obtained in the same manner. It is black as charcoal, is not oxidated either by water or muriatic acid, but aqua regia and fluoric acid dissolve it, and with the last, hydrogen gas is disengaged. It burns at a low tem perature with great intensity. It combines with sulphur, forming a brown chesnut coloured substance, insoluble in muriatic acid and in alkalies, but which burns with splendour, forming sulphurous acid and zirconia." but fluoric acid, particularly if a little nitric acid is added, speedily dissolves it. Silicum does not decompose nitre, unless exposed to an intense heat; but it detonates with carbonate of potash at a red heat. When silicum is heated with saltpetre, and a piece of dry carbonate of soda is plunged in the mixture, a detonation immediately takes place. By passing the vapour of sulphur over red hot silicum, the metal becomes quickly incandescent. When the combination is complete, which rarely happens, the resulting substance is of a white earthy appearance, and decomposes water with extreme rapidity Water dissolves the silica, and sulphuretted hydrogen gas is cooled. By this means, a solution of silica may be obtained so highly concentrated, that during the evaporation it coagulates, and deposits portions of this earth in the form of transparent masses, like gum. When silicuret of potassium is heated with sulphur, it burns ra pidly, and leaves, when dissolved, the silicon in a state of purity. In chlorine, silicum takes fire at a red MR. EDITOR,-If the following heat; a liquid, colourless, or slight-be suitable for your pages, I shall ly tinged with yellow, results, ex- be obliged by their speedy insertremely volatile, having the odour tion. 1st. What is the best method of cyanogen, and which, with water, of obtaining sulphur from nativeg deposits silica in the form of jelly. sulphuret of iron, upon as largel It is very easy to produce silicum. scale, so that sulphuric acid mays The fluates of silica and of potash be obtained from the disengaged" or soda, heated to redness, to dis- sulphur, and sulphate of iron from sipate the water, is introduced into the residue? a glass tube, closed at one end." Small pieces of potassium are then put in, which are mixed with the powder, by heating them till the metal melts, and by lightly striking the tube. Apply the heat of a lamp, and before a red heat is obtained, a detonation takes place, and silicon is reduced. It is allowed to cool, and then washed with water as long as any thing is dissolved. At first hydrogen gas is set at liberty, because silicuret of potas sium is obtained, which cannot exist in water. The substance washed is a hydroguret, of silicum, which burns with rapidity in oxygen gas at a red heat, though the silicum is not completely oxidated. QUERIES. སཾ སྠཽ ནཱ 2d. What is the best method to obtain carbonate of ammonia from" the ammonia disengaged during the e manufacture of coal gas? In reading your Analysis of Scientific Journals for May, I per ceive you have made some obser vations on an article in the Annals: "Remarks on Solar Light and Heat, by Baden Powell, M. A." With the import of those remarks I cordially agree; but as the subject is of great importance, being con- ft nected with most of the phenomena of nature, and is capable of receiving further elucidation from the luminous rays which are every it where emanating from the orb of reason, I request you will not dis miss the subject from the pages of What method is best adapted to obtain acetate of tin, upon an extensive scale and at a cheap rate? JUVENIS. MR. EDITOR, I understand that at present there is among fashionable people a great rage for bright bay horses, and that horses of this colour fetch a much higher price than of any other. Jockies, Sir, are knowing kiddies; and it is said, that some of them have found out a means of colouring horses of a most beautiful bright bay,I have frequently read of washes to make ladies' hair of different colours; and have heard even of a learned professor in a celebrated university of the north, having car ried this art so far, that he appears the same sub- before his admiring pupils witho Is solar light different in its na- and well wisher, A but P. S. Since writing the above, a friend of mine, a reader of the Chemist, has requested me to insert the following, hoping you will favour them with a place in your f his hair stained of a different co- season compensate the deficiency of another. In this point of view, wheat and grains of all kinds, which can be kept for two or three years, are much the most valuable articles of food. Whatever serves, therefore, to preserve grain in a state of perfection, tends to equalize the quantity of food which can be obtained every year, and thus to relieve society from the alternate vicissitudes, which the seasons bring, of dearth and plenty. There are also, probably, few of our readers who have not seen those immense granaries on the borders of the Thames, in which, when grain is stored up, it has to be frequently moved and turned, at a considerable expense, to preserve it. Under these points of view, it appears of some importance to know how to preserve grain in the greatest perfection, and at the least expense. In many parts of the Continent, this is done by depositing it in holes constructed in the earth for this purpose; and this has always been done on the idea that if air and moisture could be completely excluded, the grain might be preserved for any length of time. It has, in fact, long been known that grain or flour so stowed in casks as to be perfectly air-tight, has been preserved for years unaltered. Under the influence of this same idea, in 1819, the Count Dejean, according to the Annales de Chimie, caused some casks to be made, which were covered with lead, and into which grain of different kinds, properly dried, was put, and then the casks were her'metically sealed. They were opened at the end of three years, and the grain found to be in a perfect state of preservation. As grain in this state sustains no loss, and requires no attention, it is supposed that the expense of the casks and of the lead will not be equal to the cost of preserving grain not so guarded. There can be no doubt of the accuracy of the principle on which this process proceeds; and as little doubt, we believe, that in this country it might be brought into practice by some still cheaper EXTRAORDINARY FALL OF THE BAROMETER. The journals of Germany remark an extraordinary fall of the barometer on January 23d, 1824. On that day it stood at 26° 11' at Leipsic, it having been (says the Journalist) only three times as low, namely, in 1799, 1782, and 1783, during the whole of the eighteenth century. On referring to the meteorological journals kept in Eng-, land and France, we observe, that in both these countries also the barometer stood very low on the same day. By the meteorological diary given in the Quarterly Journal of Science, it appears to have been at 289 70'; and by the météorological observations in the Annales de Physique et Chimie, it stood at 730° 71', being in both cases considerably the lowest of the month, and much below the average of the year. At Paris and Leipsic the wind was S.W.; at Althorpe, in Northamptonshire, W.S.W. and N.W.; and it rained somewhat both at Paris and Leipsic. POISON OF THE UPAS TREE. THE poison of the upas tree has lately been subjected to analysis by Messrs. Pelletier and Caventou. It appears there are two species of the upas poison; one is the produce of a plant, called by M. Leschenaut, strychnos tieute; the other, the terrible upas tree, is called the anthiaris toxicaria. These chemists have made experiments on both poisons, and state the following facts as the result: The poisonous principle of the strychnos tieute is that alkali which has before been detected in the strychnos nur vomica, and to which these chemists give the name of strychnia. From the upas they obtained it very pure; and half a grain of it, diluted with water, injected into the pleurd of a rabbit, destroyed the animal at the end of fifteen seconds, by one terrible attack of tetanos. A quarter of a grain dissolved in diluted acetic acid, given to another rab › bit, produced a still more terrible and speedy dissolution. The poisonous principle of the other upas tree, or anthiuris toricaria, is a bitter substance, soluble in water and alcohol. This bitter substance is composed of a colouring matter, of an acid, and a particular substance, which seems to be the active part of the poison, and which these chemists suppose to be a vegetable alkali. This vegetable alkali has the same effect on the animal economy as the poison of the upas tree, but is much more energetic. It differs somewhat in its action from strychnia, the former producing convulsions, with relaxation, and not being so speedy in its destroying effects as the latter, which seems suddenly to arrest with a single convulsion the whole functions of life. THE BARK TREE. THE following is an extract from a Report lately made by the celebrated traveller, Baron Humboldt,'to the Academy of Sciences at Paris, on ba work of Mr. Auguste St. Hilaire, 1 who returned to France not long ago, from the Brazils, bringing with him 7000 plants, 2000 birds, 16,000 insects, and 130 mammiferous animals. "The discovery," says the Baron, "of the true cinchona in the eastern part of South America, far from the Cordilleras, must strike those who attend to the distribution of vegetables over the surface of the globe, and the geological causes which have influenced it. At present not a single species of cinchona is known to exist, not even the exostema, either in the mountains of Silla de Caraccas, where the befaria, the aralia, and the thibaudia, and other mountain plants of New Grenada grow, or in the wooded mountains of Caripe or of French Guiana. This total want of the cinchona and exostema genders on the table land of Mexico, and on the eastern parts of South America, north of the equator, is more surprising, because the Antiles are not destitute of species of bark 1 trees. The quinina of the Cordilleras does not extend further east in the northern hemisphere than the 72 degree of longitude west from Paris, or the mountains of Micachista of the Sierra Nevada of Merida. The cinchona ferruginea, C.Vellozii, and C. Remijiano of Mr. St. Hilaire grow on the table lands of the province of Minas-Geraes, at the height of 100 metres, in a temperate climate between 22° and 189 of southern latitude. They are regarded as certainly indicating the presence of minerals containing iron wherever they grow. The bitter and astringent bark of those quinina (Quina da Serra) of the mountains of Brazil resembles very much in its flavour the quinina of Peru and of New Grenada. Their febrifuge qualities are not, however, so strongly marked as those of a still more celebrated tree, the strychnos pseudoquina, which is found in the diamond districts, in the deserts of Goyaz, and in the western part of Minas-Geraes. Of all the medicinal plants of these vast countries, the Quina do Campo, or strychnos pseudoquina, is most in use, and best known. The physicians of Brazil give the bark in powder and in decoction; and it is a beneficent gift of nature to a region where intermittent fevers are unfortunately too frequent. The virtues of the strychnos pseudoquina, as a febrifuge, are found not to be inferior to the best species of the cinchona of the Cordilleras; and though the former has not at Brazil entirely superseded the use of imported bark, it may one day be exported to Europe in great quantities. M. Vauquelin has analyzed the strychnos, and found in it a peculiar acid, but neither brucia quinina, nor any of the poisonous principle found in the strychnos nux vomica. It was before known that strychnos potatorum was destitute of this deleterious principle, and that the pulp of the fruit of the nux vomica might be eaten without any danger. The various parts of a plant do not all contain the same principles, and if in the same family of plants, in the same gender, and in plants of an analogous structure, we do not find very striking chemical differences, it must be recollected that was not sensibly diminished 1-50th part. I supposed that this gas, thus exposed, was decomposed, when, on allowing bubbles of it to escape through the mercury, it did not burn; it appeared, however, that it was not entirely decomposed, for, some time afterwards, having lifted up the bell-glass, in which it was contained, suddenly, it caught fire, and deposited a good deal of sulphur. differ in the proportion of their phosphorus. CHEMICAL SOCIETY. at THE Editor hopes that the present notice, though late, will not prevent any of the friends of the Chemical Society from attending the proposed Meeting. He has received W. J.'s permission to name him, and his assent to the meeting Ex. 2nd. One hundred taking place at his offered room. those gentlemen who wish to form As before announced, therefore, among themselves such a Mr. Jones's, No, 55, Great Preswill have the goodness to cot-street, at eight o'clock on Saturday evening. The Editor must again express his own regret at being unable to attend, more particularly as he has been requested by a country Correspondent to make known the regulations adopted in such a Society. At the same time, he will be happy to make the Chemist the vehicle for submitting to public perusal any of the proceedings of the Society which he and they think worthy of publication. measures of phosphuretted hydrogen gas were heated with sulphur; their volume increased about 1-10th, and they were converted into hydrosulphuric acid gas.Ex. 3d. One hundred measures of bihydroguret of phosphorus having been heated with sulphur, were decomposed, and changed into sulphuretted hydrogen gas, but they did not sensibly alter their volume more than about 4 measures. WATER. To the Editor of the Chemist. SIR,-Could you, or any of your Correspondents, inform me of a receipt for purifying water which contains iron? By giving me am answer in some following Number you will greatly oblige, June 12. A.B.D... Ex. 4th. One hundred and twentyfive measures of phosphuretted hydrogen gas, mixed with distilled water, and placed in a dark situation, were speedily decomposed the phosphorus was deposited, and the gas no longer took fire in the air. The diminution of volume was 1-25th. Ex. 5th. ON THE PURIFICATION OF Phosphuretted hydrogen gas placed in contact with distilled water, and exposed to the cold produced by mixing ice and salt, was speedily decomposed, though in a dark place. Water and cold, then, promote more actively than the sun, the decomposition of phosphuretted hydrogen. This decomposition cannot be attributed to the presence of air in the water; for its volume is not sensibly diminished; besides, this gas is little soluble in water. These experiments prove that phosphuretted hydrogen gas and bihydroguret of phosphorus are simple solutions of phosphorus in hydrogen gas, without its being condensed; for the small augmentation of volume which took place in melting sulphur in bihydroguret of phosphorus is of no consequence; besides, this augmentation takes place in both. Thus these two gases con tain volumes of hydrogen gas equal to their own volumes, and only TO CORRESPONDENTS/ JUVENIS, and James Marsh, in our next. We have unfortunately mistaid the communication of ANOTHER DAIRY MAID, or it would have appeared in the present Number. We feel we dos not deserve any further favours, but knowing that woman's charity is always greater than man's failings we hope we shall hear from her again. **Communications (post paid) to be addressed to the Editor, at the Pub lishers. London: Published by KNIGHT and LAN |