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ancient painting, and gives us the life of Polygnotus at great length. . To this succeed short accounts of some other painters; and the work is closed by a long life of Zeuxis, which was before published separately.
In treating of ancient sculpture Mr. H. presents us with a tedious digression on the olympiads--because the periods of ancient artists are calculated by these epochs! In p. Ixxvii. &c. the works of Lescheus Pyrrhocus, and other ancient writers, now lost, are quoted with the same familiarity as if printed by Aldus. How ignorant one may be in appearing learned! Mr. H. in aspiring to write Italian, fometimes makes his Italian a kind of English; the following sentence, p. xcv. appears to be neither Italian nor English.
Where under their leafy honours, at length, poets by pro. profession sung to perpetuity the blooming theme.
To the learned reader any information, contained in this motley compilation from Adriani and Dati, will have no no. velty; and to the unlearned the Italian pages, and the size and price, will form material objections. We shall, however, take leave of Mr. Hickey in good humour, with the following extract, translated from Carlo Dati,
• Zeuxis, with great reluctance, or very feldom, employed his pencil or his genius on common or trivial subjects; and, entertaining the idea of going out of the beaten track, a fancy struck him of representing, in a shady spot, enriched with foliage and with flowers, a female centaur, with the equaline part at reft upon the ground, in such a position as that the ħinder part appeared under the crupper. "The feminine part appeared elegantly raised up, and inclining upon the elbow. One of the fore feet was kneeling, with the hoof retired inwards, and encurved within itself; the other was raised, and the hoof, towards the ground, shewed just that position of it which a horse makes when he endeavours to get up. With her were two little centaurs, one in her arms, whom she suckled as a woman, the other centaur was fucking at the teat, in the way that foals do. In the upper part of the picture, a centaur, her husband, as from a place where he had been watehing, seemed to rush out upon them; and, smiling at her, held the cub of a lion in his right hand, and seemed to raise it up by way of frightening the little centaurs.
• The centaur was represented as rough, grim, and vulgar, with his hair all tumbled and clotted, his skin rugged and bristly, not only where he appeared as a horse, but even in his human part, with his shoulders raised up; and his face, though in a laughing expression, yet every way brutal and ferocious. The equaline part of the female centaur was represented as a beautiful mare, of that untamed Theffalian breed, which never M in 4
fube submits to any burden. The half which appeared as a woman was drawn throughout with extraordinary beauty, except the ears, which were coarse and deformed. But in the joining, where the woman united with the mare, it was done with such skill, and so beautifully blended, as to elude discovery. The little cen. taurs were in colour resembling the mother. One of hem was exactly like the father in coarseness and rufticity; and, though at that tender agr, his aspect bore the character of fierceness and barbarity. But singularly admirable was the artist's observation of nature, in making the little centaurs fix their eyes upon the young lion, yet closely adhere to the mother's breast.
* This piąure, also, in the other departments which the learned admi e in the art, was very capital, in the beauty of exprellion, intelligence of light and fhade, the colouring, and in the facility and judgment in the execution of the pencil.'
Annales de Chymie, Vol. VI. and VII. (Continued from Vol. II,
New Arrang. p. 100. W e now resume the two last volumes of these Annals;
published in the present form, and shall proceed in the usual order. The first essay is an extract from M. Crell's Journal, by M. Haffenfratz. These facts are miscellaneous, and it will be fufficient for us to notice some of the most important. The zir-kons, a peculiar fossil discovered in the German mines, is found to contain a new earth in a pretty large proportion unit. ed with flint, and a very litrle calx of iron. The adamantine spar also contains a very particular kind of earth, which is, with some difficulty, soluble, when combined with clay, but is totally insoluble in alkalis and acids, at the moment of separation. The acid, in the Saxon ore of mercury, is found to be the muriatic, not the sulphuric, M. Rafpe has confirmed the observation of Bergman, that manganese would attract humid. ity, and calcine in the open air. The supposed earth of Diamond, from China, appears to be only the dust of the adamantine spar. M. Schuler makes a blue fealing-wax with the mountain blue, purified by melting it with an ounce of talc.
M. Schuler has made some improvements, though of no grcat importance, on the preparation of tartarised tartar. He prepares in a very neat way the tartrite of foda from a mixture of cream of tartar and foda, separating the pot ash, by adding Glauber's falt. The vitriolated tartar is separated by taking advantage of its property of diffolving less easily in cold than in warm water. This chemist prepares also the diffoluble tartar by means of borax, without adverting to the chemical change occafioned in the cream of tartar, by a double elective attraction. The tartarised steel he prepares by mixing two ounces, two drachms, of steel with twelve qunces of cream of
he original - ernambouiento
tartar, and pouring water on the whole : in twelve days the union is complete, and twelve ounces of tartarised steel easily soluble in water, may be obtained by evaporation. The fame author found that the acid of the black elder was of the tartarous kind approaching to the acetous.
M. Born has discovered, that the fossil styled the spar of zinc is only the tungstein chryftallifed, containing, however, some proportion of zinc. M. Lowitz has said that charcoal is soluble in pot ash, and many other substances, imparting a brown colour; but M. Hahneman, when he repeated the experiments on smaller quantities, could not succeed. As M. Lowitz' former experiments on the antisceptic power of charcoal, though at first denied, have been fince confirmed, we have the fuller confidence in these. M. Bofer has made many trials to fix the colour of the wood of Fernambouc, in good preservation, on linen and cotton. The method which ana swers best is, mixing a quart of distilled water, with an ounce of alum, and a sufficient quantity of clay, united with two ounces of Fernambouc. When reduced to three quarters of the original quantity, it becomes glutinous, and the linen or cotton must be put in. M. Weftrumb has at last fucceeded in separating the alkali from common falt, but the process is tedious and not likely to answer for the purpose of manufacturers M. Born mentions the discovery of a new kind of cinnabar of a much more brilliant colour, which breaks like fpar, and seems, by this evidence, to contain some lime.
The roots of the mercurialis perennis differ greatly in their fizes: some are very slender, and others thick: of the latter, some turn, on being exposed to the air, of a beautiful violet and brilliant blue. This colour is soluble in water, and not changed by alkalis, vinegar, or alum. The thick roots, which do not assume this blue colour, give a beautiful carmine red. M. Westrumb, in his analysis of calculi of the bladder, has been able to discover no acid : he finds only an oily substance, a little ammoniacal falt, and a calcareous phosphat. The same author confirms M. Lowitz'observations on the effects of charcoal, in purifying and whitening alkaline and neutral falts.
It has been lately supposed in Germany, that cobalt was susceptible of magnetism ; but M. Kunse-Muller, in repeating the experiments of M. Kohl, discovered that this was owing to an accidental impregnation of iron. A little vitriolated lead has been found in the oil of vitriol manufactured in England: it is discovered in the powder precipitated by mixing equal quantities of water with the acid. Manganese has been obtained pure, by the humid way, and it seems now also to be generally agreed, that phosphorus is a constituent part of the
Pruflic Pruflic acid. Some calculi, found in an abscess, appeared very nearly to resemble bezoars, being composed of phosphorus, a fatty oil, calcareous earth, and a little fixed acid. M. Brugnatelli tells us, that the benzoic acid may be obtained by means of diluted alcohol, and the chrystals resemble those of the sublimed acid. This acid may be managed so as to procure a new sympathetic ink, whose traces become legible by exposing them to nitrous gas or smoaking nitrous acid. From M. Weltrumb's experiments, which he has not yet published at length, all the vegetable acids appear to be only combinations of the phosphoric and fixed air.—The schists of Normandy are sup, posed to contain a large proportion of magnesia,
M. Vogel has discovered an ingenious method of amalgae mating mercury with iron, by rubbing half an ounce of powdered filings of iron, with an ounce of alum. This mixture will amalgamate three half ounces of mercury, and the alum may be afterwards washed away, -The oils of parsley and fennel seem to contain oxalic and tartarous acids.-Black'ink, which smells like a rose, may, it is said, be obtained by a decoction of the tormentilla erecta, It is made in the usual method, and the proportion of vitriol is three drachms to a decoction made with seven ounces of water. M, Vayler's method of fixing on cotton or linen a beautiful black colour is, first to immerse the linen in a solution of litharge prepared by adding it to a very diluted nitrous acid; then successively to dip it in the infusion of galls, and solution of vitriol. The tin of Saxony, it is found, contains no arsenic; that of Sweden a large proportion, though not in such a state as to be dangerous, M. Westrumb has obtained red vapours of nitrous acid, and even water acidulat, ed with the same acid, by burning a mixture of hepatic and inflammable airs, in vital air; and burning deal and agarics in the same oxygen. This seems to confirm Dr. Priestley's opie nions. The nitrous acid may be also oxygenated by distilling it from manganese, and this acid will diffolve tin, without becoming foul by a slight dilution, M. Hermbstadt seems to have procured the acid base of tin, in a less exceptionable way, with less of suspicion of acidity from the mineral acids, by eniploying the dephlogisticated nitrous acid. The purest and most concentrated acetous acid may be procured, we are told, by M. Brugnatelli, from the barytic acelite--The flowers of the alcca purpurea are said to be the nicest and best reagent to discover acids and alkalis--these are some of the more important chemical íacts in the first abstract.
The second subject is an abstract on M. Du Trone's work on the sugar cane, which we have long since noticed. This part consists clicily of the inethod of manufacturing sugara drawn from the volume,
· A report on the art of aflaying gold follows. Six circum. stances seem principally to influence the operation, 1. the quanity of acid employed in the parting : 2. the concentration of the acid: 3. the duration of the process: 4. the quantity of acid employed at renewing the process : 5. its concentration ; and, 6. the duration of this process. If either of these circumstances are unfavourable, it may occasion the loss from half the thirty-second of a carat, to four times that quantity. If all were to be unfavourable, the deficiency would be greater. These data, however, account for the variations in different aslays by different operators, and point out the necessity of one steady, constant, uniform method, which is afterwards described, but is incapable of being abridged.
The academicians' report on the antimephytic pumps, is in many respects curious, but not of a sufficiently delicate nature to be explained in a popular work. It relates to the method of clearing the fosses d'aisance, from their foul air and foul matter, a circumstance seemingly of great importance in Paris. The inflammable air arising is fupposed to be injurious to health, but injury is in general derived only from the inflammable air escaping in consequence of the putrefaction of vegetables, or of human bodies in a diseased or a crowded state. A little historical introduction respecting the conduct of ancient and modern cities, in these conveniences, is curious.
The letter of M. M. Sylvestre, and the abbé Chappe, contains adescription of a more convenient machine to repeat the experiments of M.M.Troostwych and Derman, on the decomposition of water, by means of the electrical spark. The result of the experiments is to be the subject of a future communication.
M. Fourcroy's analyfis of a black ferrugineous sand from the island of St. Domingo follows : it seems to be a pure calx of iron, with about it, of chalk, and some true fand. .
M. Pugot and Damy obtained a patent in 1785, for the purpose of plating copper vessels with silver. Various circumItances have occasioned the foundation of the operation to be enquired into, and the acadimecians were principally directed to examine, whether the copper was completely covered ; what was the thickness of the silver, what the nature of the union between the two metals, and how soon the filver may probably be destroyed by use. The enquiry is favourable to the manu. facturers: iso of a line is found sufficient thickness to guard the copper from acids ; but they recommend, rather, for kitchen utensils, the silver to be is of a line, or to of an English inch. As the expence of the workmanship is the fime, they think it may be æconomical to have it still more solid. The union is very firm, and, as only the finest Glver
can be used, they think this manufacture superior to solid Alver, : which is generally allayed by a mixture of copper.