This acid appears to produce, in a fhort time, the fame effect on colours that would refult from their being long expofed to the action of the atmosphere: it fo entirely destroys thofe of vegetables, that they cannot be restored by alkalies; that of the fyrup of violets, and of the turnfole, inftantly vanishes, though the latter feems to retain a yellow hue, which, however, gradually disappears. By thus acting on colours, the dephlogisticated marine acid lofes its peculiar characters, and is reduced to common marine acid. Obfervations on Aqua Regia, and on fome Affinities of the marine Acid. By the Same. The properties of aqua regia were, by Bergman, afcribed to the power of the nitrous acid to attract the phlogifton, which the marine acid is fuppofed to contain; confequently, the latter becomes dephlogisticated. M. BERTHOLET, on the other hand, produces an ingenious set of experiments, from which he deduces the following conclufions: 1. That in a mixture of the nitrous with the marine acid, a portion of the latter is combined with a part of the vital air contained in the former, and is thus expelled in the form of dephlogisticated marine acid; but that all the nitrous gas, both that which was combined with the nitrous acid, and that which is generated in the process, is retained in the aqua regia, 2. That the marine acid attracts the vital air from the nitrous acid, not merely by a greater affinity, but by the action of a double affinity. 3. That the folution of gold and mercury in aqua regia is owing, not to the action of the dephlogifticated marine acid, but to a combination formed by the concurrence of mutual affinities of the air exifting in the nitrous acid, the marine acid, and the metal. The remainder of the memoir contains obfervations on some affinities of the marine acid, compared with those of the vitriolic and nitrous acids, in which the writer attempts to reduce to the known laws of affinity fome phenomena which feveral chemifts have fuppofed to be anomalous. On the Decompofition of Spirit of Wine, and of Ether, by means of vital Air. By the Same. M. BERTHOLET found that dephlogisticated marine acid, on being mixed with spirit of wine, was abforbed and reftored to its natural ftate. This abforption was accompanied with heat fufficient to melt the ice that furrounded the veffel, and gave the spirit a smell of æther; but this odour diminished on the abforption of a greater quantity of the dephlogifticated marine acid by the spirit, which at last acquired a ftrong smell of vinegar, and, when faturated with mineral alkali, became of a deep yellow colour, inclining to brown: this was diftilled in balneo maris, and yielded at firft an æther, and afterward a fluid, which appeared to be only water, with a fmell APP. Rev. Vol. LXXVIII. U u like like that of burnt fugar; the refiduum was a mixture of fea fatt with a faccharine fubftance, and the dephlogifticated marine acid, when impregnated with it, loft its colour and recovered its acidity. Similar experiments were tried with the vitriolic æther, which likewife decompofed and abforbed a large proportion of dephlogifticated marine acid. On faturating the marine acid which had refumed its acidity, with mineral alkali, it did not change its colour, but yielded a confiderable quantity of a very light aromatic oil, refembling the fweet oil of vitriol. When diftilled, what came over was, firft a small quantity of æther, and afterward water; the refiduum, after evaporation, was fea falt, of a yellow colour. From these, and several other experiments, M. BERTHOLET concludes, that spirit of wine confifts of a very fluid oil combined with fugar, with inflammable air, and a portion of water. If an acid, the vital air of which is capable of uniting with a part of the oil and inflammable gas, be added to fpirit of wine, the component principles of the fpirit will be difunited, most of the inflammable gas, together with the more fubtile part of the oil, will be rendered volatile, and in this combination a small portion of the acid employed in the procefs will be carried off, while the fugar and the groffer part of the oil will remain in the retort, half burnt by the vital air extracted from the acid. Æther is here confidered as an oil feparated from the fpirit of wine, combined with a large quantity of inflammable gas, and a little of the acid employed in its production. Analysis of volatile Alkali. By the Same. By diftilling two ounces of ammoniacal nitre well dried, he obtained a confiderable quantity of what Dr. Priestley calls dephlogisticated nitrous air, and one ounce and * forty-three grains of a fluid, which exhibited characters of great acidity; there remained in the retort about a dram of ammoniacal nitre not decompofed. The fluid thus obtained was again diftilled in balneo maris, and the refiduum was four drams and thirty-two grains of ammoniacal nitre, which had been volatilized in the preceding diftillation without being decomposed. On faturating, with the vegetable alkali, the fluid which came over in the last distillation, no smell of the volatile alkali was perceived; and, by evaporation, about three drams and fixty five grains of water, remarkably pure, and refembling diftilled water, were obtained. Here it is obferved, that as water is found to confist of about fix parts of vital and one of inflammable air, and as it has been fhewn by experiment that the nitrous acid contains about 0,7 of * The French divide their dram, which is equal to about 59% grains Troy, into 72 grains. vital air, the volatile alkali must in this case have yielded about 40 grains of inflammable air, in order, together with the vital air of the acid, to constitute water. Hence it is argued, that the inflammable gas of water is a conftituent part of the volatile alkali, which, from feveral experiments, appears, befide this, to contain a certain quantity of mofette or phlogisticated air, which is to that of the inflammable gas in the ratio of 121 to 29. Obfervations on the Combination of vital Air with Oils. By the Same. In the courfe of his experiments on the dephlogisticated marine acid, he had found that the expreffed oils expofed to it became fo dense as to fink in water, even when the fpecific gravity of the latter was increased by the marine acid generated in the process. Hence he concluded, that the increased denfity of the oils was owing to their combination with vital air. In order therefore to try whether air in its elastic state would combine with oil, and in this cafe retain its properties, he put fome copper filings into a vial of newly expreffed oil of almonds, which he immediately corked: the metal, however, was not affected, nor did the oil change its colour; whereas fome of the fame oil poured on the filings and expofed to the air foon became of a green colour, which indicated a folution of the copper, The fame effect was produced in a fimilar mixture placed in a veffel filled with vital air, which, in confequence of this procefs, underwent a confiderable diminution. By the combina tion of air in various degrees with other principles, both primitive and fecondary, our Author thinks many of the operations of Nature may be explained. This he exemplifies in his endeavours to account for the composition of water, and the formation of wax, which he fuppofes to be only an expreffed oil combined with vital air. Continuation of Refearches concerning the Nature of Animal Subfances, and their Relation to Vegetable Subftances. By the Same. Experiments on a Smoking Oil of Vitriol from Saxony, and on the concrete volatile Salt obtained from it by Diftillation. By M. DE FOURCROY. ANATOMY. On the fpermatic Veffels of spinous Fish. By M. BROUSSONET. On the Refpiration of Fish. By the Same. These memoirs are curious and interefting, efpecially the latter, which contains judicious obfervations on all those branches of animal œconomy bearing relation to that mentioned in the title. On the Clavicles, and on the clavicular Bones. By M. Vice D'AZYR. Naturalifts have given the appellation of claviculated to those animals which, like man, have the fternum and acromium connected by the clavicle; but, in the opinion of our Author, they have excluded from this clafs many genera which ought to U u 2 have have belonged to it. By carefully diffecting the muscles of quadrupeds, he has difcovered clavicles in feveral, in which they had never yet been perceived: these differ indeed from the clavicles in animals of the former clafs, as they are shorter and more irregular, concealed among the muscles, and partly ligamentous; for which reafon he has diftinguifhed them by the name of clavicular bones. Hence he propofes an arrangement of quadrupeds into three claffes; the first confifting of those which have complete clavicles, the fecond, of those which have only clavicular bones, and the third clafs, of those which have neither. To exemplify these observations, he has given a minute defcription, illuftrated by well-executed plates, of the clavicular bone, with the adjacent parts, in the rat, the rabbit, the hare, the Guinea pig, and the cat. It is, however, unfcientific to adopt the internal ftructure of natural objects for the distinguishing characters of a claffification. On the anatomical Hiftory of the Tendons, and especially of their mucous Capfulæ. By M. DE FOUR CROY. In these two memoirs M. DE FOUREROY, after an historical view of the obfervations of anatomifts on this fubject, gives an account of the ftructure, fituation, and ufe of the mucous capfulæ of the tendons, and adds a particular defcription of thofe of the human body. NATURAL HISTORY. Obfervations on the Sea Wolf. By M. BROUSSONET. Account of the Cupreffus Difticha of Linné, or the deciduous Cypress. By the Abbé TESSIER. This kind of cypress, which grows in great abundance in the fwamps near Philadelphia, has lately been found to thrive in France. It is valuable on account of its timber, which is faid to be proof against the worm, and to be more durable than any other. Thofe planted in France about fifteen years ago are now thirty-fix feet high, and four feet in circumference at the base. Obfervations on the Manner of making Herbals. By the Abbé HAUY. As the natural colours of flowers thus preferved are apt to fade, the Abbé fuggefts a method of fubftituting artificial colours in their ftead. With these the paper is to be stained, on which the flowers are impreffed. On the Structure of feveral metallic Cryftals. By the Same. Concerning the Distribution of Vegetables into the fame Number of Claffes with thofe eftablished in the animal Kingdom, and, like those, founded on the various Degrees of Perfection of the Organs. By the Chevalier DE LA MARCK. After infifting on the inconvenience attending the fyftems of Tournefort and Linné, the Chevalier proposes to diftribute the 7 vegetable vegetable kingdom into fix claffes, analogous to those of animals, as in the following table: On the Figure of the Earth. By M, DE LA LANDE. It is a common opinion that the figure of the earth, as deduced from the comparative length of pendulums, is different from that which is indicated by theory, and the measurement of degrees of latitude but M. DE LA LANDE fhews, in this memoir, that the fuppofed difference arifes merely from confidering the earth. as a homogeneous body; whereas, if we admit that the ftrata, of which our globe is compofed, increase in denfity as they approach the centre, the refult of the obfervations made on the pendulum will agree, not only with that obtained from the measure of the degrees of latitude, but also with the theory and the laws of hydroftatics. This he illuftrates by an examination of the obfervations made by Mr. Lyons, who accompanied Lord Mulgrave in his voyage toward the North Pole, compared with those made by Meflrs. Graham and Campbell in London and in Jamaica, and with thofe of the French academicians. On the Origin of the Zodiac, the Explanation of the twelve Signs, and Sir Ifaac Newton's Syftem of Chronology. By M. LE GENTIL. This memoir is only a fhort view of a larger work on the fubject presented by the Author to the Academy. He conjec tures that the zodiac was invented in the age of Atlas, four thousand two hundred and forty-two years before Chrift, when he calculated that the canicular period muft have commenced, and that the stars in the beginning of Virgo were in the fummer folftice, which was confidered as the renewal of the year. He' afferts that this conftellation was intended, not to indicate the season of reaping, but as a reprefentation of Ifis or Ceres, under which figure the earth was deified by the Syrians, and all the eastern nations. In connection with this, he observes that the fign of Gemini, which is in the ninth month after Virgo, was defigned to point out the fertility of the earth, by the allegory of twins. M. LE GENTIL alfo defends Newton's opinion, that the fphere of Eudoxus was that of Chiron; and vindicates his calculations against the objections of Whifton, who did not, he Uu3 fays, |