You to contemplate, without fear, the variety and grandeur of the objects which compofe the fcience of nature. What, then, would he have thought of the man who rifques his life a thousand times to extend the limits of that science? You have proved to me, that even in this world we may conceive fenfations which we have never experienced, tafte enjoyments which feem to belong to a different fpecies, and collect ideas and images of which our univerfe has never offered to us the firft germ or the first outline. Pardon me for fpeaking fo long of the acceffories of your labour. You have anatomifed the world; but it is a living body which, ferves you as a study, and which you have taught us also to admire. Columbus did not expofe himself to more dangers than you; but he carried to America the box of Pandora, and you have brought from Mont-Blanc the most falutary plants. You have difcovered, amidft the chaos, the mark of the divine hand which created the universe. have elevated my foul, in making me fee thefe magazines of the world; and I perpetually lament my weakness, which will not permit me to follow your fteps. But my imagination frequently fupplies my want of power. perufing your productions, I hear the deep crafh of the avalanches, and the crackling of the electric matter. Filled with terror and admiration, I fometimes perceive the tomb of a rafh hunter; I fee his fpirit wander peaceably in these folitary places, and I feel that I envy him. It feems to me, that I would willingly finish my days with M. Necker in thefe delightful retreats, to render there a last homage to nature and to conjugal love, which alone remain to us amidst the wreck of all the illufions of life. He has entrufted me with the charge of defcribing to you what we have both felt; we have, while we have admired your courage, together trembled at your danger; and, reflecting on the ties which attach us to you, we believe we have a right to recommend to you the care of a life which is very dear to us.' In From the extracts which we have offered, the nature of thefe Neckeriana, as they may be called, may be judged. Madame Necker appreciates the merit of her literary friends more highly than other perfons have done; but this is not unpleasant; it is the involuntary exaggeration of friendship, and we readily pardon it. APP. VOL, XXIV. NEW Arr. M.m Annales de Chymie, Vol. XII. XIII. XIV. (Continued from IN the twelfth volume of these annals, we meet with a memoir, by the abbé Hauy, on fome varieties of the fulphat of barytes, or heavy fpar; but an abftract of it would be unintelligible without a diagram. M. Giobert communicates a procefs for preparing Kunckel's phofphorus from urine, more eafy and economical than that employed by Scheele and Ghan with the bones of animals. Thefe minute details are not adapted to our journal. The method is undoubtedly fimple, and confifts in combining the phosphoric acid with lead, by adding a folution of lead in the nitric acid. An explanation of M. Coulomb's feventh Memoiron Magnetifm, by the abbé Hauy, follows. It is difficult to give a juft idea of the author's attempt in fhorter words than those which the abbé employs; and we fhould have examined the whole in a feparate article, if, after mature reflection, we had not feen great reafon to question M. Coulomb's original hypothefis. If this fhould not be established, the whole fyftem will fall, and the experiments will be ufeleis. He fuppofes two fluids confined in the fame needle, the molecules of which attract and repel each other inthe inverse proportion of the fquare of the diftance. While the needle fhows no figns of magnetifm, he imagines that thefe fluids neutralife each other; but, when it becomes magnetic, the neutral is decompofed, and each ingredient acts feparately. The whole is hypothetical, and is encumbered with too many ufelefs, and fome inconfiftent fuppo tions. The most advantageous form of magnetic needles, in our author's opinion, is that of two long triangles united at their bafe, called aiguilles en fleche. He alfo remarks, that the fum of the forces of feparate, fimilar, and equal needles, is more than double that of the bundle which they form when united. The moft efficacious method of conveying the magnetic virtue, is that of the double touch. Needles made of feparate lamina are very powerful. M. Coulomb exhibited one weighing 20 pounds, to which a piece of foft iron adhered fo ftrongly, as to require near 100 to feparate it. M. Cortinovis endeavours to prove that platina was known to the ancients, and called electrum. The arguments are not ftated; but they feem, from fome circum ftances, to depend on the pillars of electrum, mentioned by different authors. The meaning might be, that the pillars were encrufted with amber, or that they were compofed of a yellow marble resembling it. M. de Rafumowski, in his obfervations on the formation of granites, fuppofes that, as they are evidently cryftallifed, they must have been diffolved in a more active menftruum than water, probably the sparry acid: but the idea is not fupported by Recent obfervations. M. Carminati gives an account of a root brought from Quito, called calagnala, which has been introduced into the Materia Medica of fome authors. is an aftringent, chiefly gummy. It refembles in many refpects, and perhaps in medical properties, the polypodium vulgare. It The ordinary fulphuric acid, it is obferved, is often mixed with some of the nitric acid: this is discovered by immersing à ftraw, previously dipped in ammoniacal carbonate (common fpirit of fal ammoniac), round which any nitric acid, that may be in the mixture, forms a white cloud. Any portion of the muriatic acid would produce the fame effects; but this is feldom found in cominon oil of vitriol. t The memoirs of the Italian fociety at Verona furnith two chemical articles. One is by M. Lorgna, who pretends that congelation not only purifies fea-water, but separates almost every kind of impurity from water. The congelation, we think, must be flow, and often repeated. The fecond is by M. Fontana, who supposes, from his experiments on the water of the marfhes of Sienna, that flints may be reduced to powder by the fulphureous acid, and thus fufpended in water. He explains, in this way, the fufpenfion of the flint in the waters of Iceland; but the explanation is unfatisfactory and ill-founded. The obfervations on the properties of muriat of tin, by M. Pelletier, form a valuable article, highly interesting to artifts. Muriat of tin is either the folution of the metal in the common acid, or in the oxygenated acid. Artists diffolvė their tin in different ways, which they ufually keep fecret; fometimes in the pure acid, fometimes, as our author fupposes, in the nitro-muriatic. We may remark that the oxygenated muriat of tin, if diluted with water, will diffolve more of the metal; and the folution is then reduced to the ufual ftate. The muriat of tin, with the fulphureous acid, is precipitated of a red colour, which foon becomes, on heating, a bright and beautiful yellow, that promises to be highly useful as a pigment. We cannot enter on the par ticular details, but may obferve, in general, that the oxygenated muriat of tin furnishes an excellent fteady mordant, at an eafy rate; that the muriat of tin attracts oxygen fo ftrongly, as to take it from many acids and metallic oxyds; that the folution of gold affords no purple precipitate with the oxygenated muriat; and, laftly, that the common muriat abforbs oxygen from the atmosphere, and may conse、 quently be employed to determine its proportion in any quantity of air. M. Gadolin, of Abo, communicates the refults of experiments on twenty fpecies of lichen, as materials for dye ing, by M. Weftring: many of them are natives of our own country, and their management is fimple and easy. A valuable effay by M. Vauquelin follows: it is entitled Chemical and Phyfiological Obfervations on the Refpiration of Infects and Worms. The fubjects of his experiments were, the gryllus viridiffimus, locufta vermivora, limax flavus, and helix pomatia. He firft defcribes the organs of refpiration, and proceeds to confider the effects which the refpiration of caterpillars and fnails may have on the air. He found that infects and worms refpire oxygen like larger animals, with warm blood, and convert it, like them, into water and carbonic acid; that this air is effential to them; and that they die as foon as they are deprived of it. Snails, he fays, have a confiderable refpiratory force; and their organs are not affected by carbonic acid or azote; but they extract all the oxygen which may be united with these airs, and do not die till the vital air is wholly exhaufted. Miscellaneous remarks on chemical fubjects occur in a letter from M. Giobert: and the volume concludes with an account of fome new chemical works. The thirteenth volume commences with two memoirs by M. Haffenfratz, containing an explanation of fome phænomena, which feem to contradict the laws of chemical affinity. Thefe are followed by a defcription of an atmospheric eudiometer by M. Reboul. The fubftance employed by him to feparate the vital air, and afcertain its proportion, is phosphorus, when burning. This method, however, is in fome refpects uncertain. M. Pelletier's analysis of what are called by manufacturers blue cinders, is not interefting to us, as they are fufficiently common in England: they contain nearly equal parts of carbonate of lime and carbonate of copper. M. Vauquelin's experiments on the folubility of common falt in folutions of different neutral falts, with the confequent phænomena, are curious. It is remarkable that a faturated folution of nitre fhould be able to diffolve common falt, and then take up more of the nitre, which it would reject before: yet fo little are general rules infallible, that this experiment may frequently be made with fuccefs. It is alfo furprising that a folution of fame falts will diffolve a larger quantity of another neutral than diftilled water alone. Sometimes, indeed, a little of the former falt is precipitated, but never without a feparation of heat. Sea-falt alfo, at the temperature of about 9° or 10° of Reaumur, is more foluble than any other alkaline or earthy neutral. It is not, however, equally foluble in higher temperatures; many neutrals will precipitate it from boiling water, while the fea-falt precipitates these neutrals from cold water. In the faltpetre refineries, common falt is feparated during the boiling; yet, to make the nitre crystallife in the cold, fea-falt is added. This phænomenon is more ftriking and decifive with fulphat of foda. In general, thofe falts which require much water in cryftallifing, discharge a proportional quantity of heat in their diffolu tion, and of course absorb as much during their cryftallifation. The quantity of heat thus abforbed, and let loose, fhould be determined with more precifion. We shall add the results more comprehenfively, as it is a fubject little understood, even by experienced chemifts. 1. The greater part of the faline folutions are decompofed by common falt, with the feparation of a quantity of heat, in proportion to the falt precipitated. 2. Some folutions depofit more of their falt than they diffolve of common falt; and the latter occafionally produces no precipitation. 3. Similar maffes of different falts require different quantities of caloric for their folution; and they have not all an equal affinity for water, at leaft at the temperature employed by M. Vauquelin. 4. The folutions are never wholly decompofed by common falt, though a little of it is always mixed with the falt precipitated: the folution, in confequence, always becomes fpecifically heavier. M. Pelletier's 4th and 5th memoirs on the union of phosphorus with metallic fubftances, offer nothing that we can felect. Phosphorus, in the mineralifation of metals, acts nearly as arfenic does. It may also, it is faid, be united to metallic oxyds; but this point requires farther examina M. Reboul's defcription of the valley of the Gave, in the Bearnois diftrict, is written with the clearness and intelligence which diftinguifh M. Sauffure's philofophical narratives. In general, it is obferved, that the vaft chains of mountains in Europe, in Afia, and America, have val. leys parallel to them, which may be ftyled longitudinal. I confefs (fays M. Reboul) that I have been unable to diftinguish, in the country through which I have passed, any traces of a longitudinal valley. That of the Gave, in the Bearnois, cuts the chain at right angles, where it is moft |