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Mem. IX. and X. relate to the Longitudes of Venice, Kiel, &c. and to the Oppofition of Jupiter and Saturn, November 1, 1774, and March 25, 1775. By M. DE LA LANDE.

Mem. XI. Obfervations on Saturn in 1775, towards the Time of his Oppofition. By M. CASSINI DE THURY.

Mem. XII. New Analytical Methods of calculating the Eclipfes of the Sun, the Occultations of the fixed Stars, and Planets, by the Moon, and in general of reducing the Obfervations of the Moon made at the Surface of the Earth, to the Place feen from the Centre Twelfth Memoir. By M. DIO IS DU SEJOUR. In DIONIS this Memoir, which contains above an hundred pages, the learned Academician applies to the folution of feveral aftronomical problems, the equations of the preceding ones. There are various important articles difcufled in this ample and most elaborate Memoir, fuch as the errors occafioned by refraction, the inflexion of the folar rays, and the obfervations that are the most adapted to afcertain the quantity of the inflexion of thofe rays that pafs near the limb of the moon. Our Academician moreover confiders the law by which inflexion varies relatively to the distance between the limb of the fun from that of the moon: He applies the preceding theories to the observations made at London, April 4th, 1764, by Mr. Short, and at Pello, by M. Hellant; and he offers fome conjectures concerning the caufe, which, in occultations of the ftars by the moon, makes the ftar appear on the moon's disk.

Mem. XIII. An Eclipfe of Saturn by the Moon, with the conSequences refulting from thence. By M. DE LA LANDE.-XIV. "Obfervation of the Occultation of Aldebaran by the Moon, April 4th, 1775, at the Obfervatory of the Marine. By M. MESSIER.

XV. On the tenth Comet, at the Obfervatory of the Marine, from the Month of August, to the 1st of December, 1769. By the fame.-XVI. On the fixteenth Comet, at the Obfervatory of the Marine, Paris, from the 18th of August, to the 25th of October, 1774. By the fame. - XVII. Occultation of the double Star y of Virgo;-Conjunction of Saturn with the Vioon, the fame Day, and the Place of a Star of the feventh Magnitude, which must have been eclipfed the fame Evening by the Moon. By the fame.-Continuation of the Memoir, printed in 1774, concerning the greatest Digreffions of Mercury from the Sun, and chiefly towards the Perihelium. By M. LE MONNIER. XVIII. On the Disappearance of Saturn's Ring. By M. LE GENTIL.

This Volume is terminated by a very curious Memoir, fent to the Academy, by the Royal Society of Montpellier, compofed by M. POUGET. It treats of the atteriffimens or acceffions of land, that the coafts of Languedoc have been long and gradually gaining from the fea. Thefe proceed from the great quantities of fand, gravel, and flints, that are carried down the Rhone, which meeting with the rapid current of the Mediter

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ranean at the mouth of that river, are stopped in their paffage to the fea, and thrown upon the coafts. The details in this Memoir are curious and inftructive.

Ak T. II.

Hiftoire de l Academie Royale des Sciences, &c. i. e. The History and Memoirs of the Royal Academy of Sciences at Paris, for the Year 1776. 40. 1779.

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GENERAL PHYSICS.

EMOIR I. Concerning the extraordinary Cold felt at Paris, and in all the Provinces of France, alfo in other parts of Europe, in the beginning of 1776. By M. MESSIER. This Memoir extends to 156 pages. The detail with which the laborious Academician relates his obfervations and defcribes the inftruments he used in making them, is most ample and circumstantial. He employed eight thermometers, two with mercury, and fix with fpirit of wine, in order to obferve the local differences of the cold in places fhut up or expofed to the open air, in different expofitions and at different heights; and by reducing the dimenfions of these inftruments to a common meafure, he has furnished future obfervers with the means of knowing these thermo. meters again, and reconstructing them in time to come, that the degree of cold obferved this year (1776) may not be loft, as that was which M. de la Hire obferved in 1709.

M. MESSIER Compares with his obfervations thofe that were made in different places at Paris by order of the Academy.This comparison, which is attended with difficulty, on account of the difference of the times in which the cold rifes to its highest term in different places, is followed by a table of the obfervations of cold made throughout Europe. From this ample table it appears, that the winter of 1776 was not accompanied with an uncommon degree of cold in the northern parts of Europe; and that, even in Sweden and at Copenhagen, the cold was much less intenfe than at Paris. It is to be hoped, that the daily improvements of meteorological inftruments, and the increafing number of obfervers will give us, at length, fome information with respect to the causes, hitherto unknown, of those variations in the winters that are quite independent on the latitudes of the countries where they are obfervable.Nor does our Academi cian omit the particular mention of the intenfely cold winters that are spoken of by hiftorical writers, Until the year 1709, they were only known by the vague obfervation of fome of their effects the winter of that year was obferved with a thermometer; but the method or art of rendering thefe inftruments fufceptible of comparison was then unknown; and uniefs we had the inftrument that was employed in the observations of 1709, or which had been, at least, compared with the thermometer with which thefe obfervations were made, it must be difficult to afcer

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tain the temperature of that year. It is much to be queftioned whether there exifts an inftrument attended with these advantaOur Academician fixes the cold of that year at about 15

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degrees.

His obfervations on the extraordinary cold felt in Paris and Senones, a town fituated in a deep vale furrounded by mountains, are curious. They fhew, in a very palpable manner, what a very great difference in temperature local caufes utay produce in different places, whofe longitude and latitude are nearly the fame. Still more curious are his experiments on the effect of the direct action of the fun upon the thermometers, at different heights and in different temperatures obferved in the fhade.

ANATOMY.

Mem, I. Concerning the refpeclive Situation of the large Veffels of the Heart and Lungs. By M. SABATIER. However unfucceísful all attempts towards an exact calculation of the animal motions have hitherto proved, it is nevertheless certain, that these motions are conformable to the laws of mechanics. Thus, for example, the diftribution of the veffels, which convey the blood to the different parts of the body, must be such, that the frequent adhesions of these veffels to each other may not occafion a presfion that would be detrimental to the circulation of that fluid :that if the blood veffels envelope the trachea arteria, or bronchia, they may not, by contracting them, obftruct refpiration; and fill farther, that if two veffels carry the blood into the fame cavity, these two currents may not be impediments to each other. It is in this point of view that M. SABATIER examines the different veffels of the lungs and the heart. There are no anastomofes vifible in the great veffels of the human body, particularly in those that lie near the heart and the lungs; but the want of thefe is fupplied by the refpective fituations of thefe veffels, which anatomical authors have not (fays our Academician) hitherto defcribed with accuracy. He endeavours to do better.He begins by defcribing the fituations of the vena cave, of the pulmonary artery, and veins; of the aorta, the laft of the large veffels of the heart in the order of circulation. He proceeds from thence to make fome remarks on the pofition of the trachea or wind pipe, and on that of the bronchia, which, though they contain no liquid, must be counted among the pulmonary veffels.

Our Academician obferves, with respect to the two veins (vena cava) which carry the blood into the right auricle of the heart, that though the one runs upwards, and the other downwards, yet they do not convey the blood in two contrary directions: He obferves, that they have an inclination, which changes thefe directions, and makes them form an angle: that the blood of the vena cava afcendens, is naturally directed towards the membrane which ftops the foramen quale, lo that the blood

pafles

paffes through this aperture in the foetus, and that, after having met with this membrane in adults, it paffes into the right au ricle, where it unites with the blood of the cava defendens, whose motion, by this wife arrangement, it cannot impede. The great curvature, or arch of the aörta, comprehends, in its concavity, the right pulmonary artery, the trachea, the cefophagus, and the left bronchia; but the action of the blood upon this arch of the aorta is only adapted to stretch it out, so that no preffion can refult from thence upon the organs which it furrounds. The fame difpofition fecures the lateral parts or branches of the trachea, after their junction with the lungs, against the compreffion of the pulmonary veins.

M. SABATIER obferves farther, that the curvature of the aörta produces in the fpine, or back-bone, of many perfons, a fimilar curvature, whofe concavity is confequently towards the left; this curvature is fometimes nor very difcernible, and at other times it does not exift. This is owing to the correfpondent curvature of the aörta, which produces this effect either by its preffion, or by its preventing the equal growth of the fpine. This phenomenon explains what our Academician has observed in perlons that are troubled with the rickets; namely, that the curvature of the fpine extends its convexity towards the right. In examining the shape of most men, an attentive eye-will feldom fail to difcover a fmall difference between the two fides of the body, which is very well accounted for by the obfervation already mentioned: This difference is the moft palpable in men, and especially in women, whofe profeffions require hard Jabour. It may be explained by the general custom of performing with the fame hand all thofe kinds of labour in which the employment of both hands is not neceflary. It might not be unworthy of the attention of anatomifts to obferve the direction of the curvature of the (pine in perfons who have a natural propenfity to employ the left hand rather than the right.

Mem. II. Anatomical Obfervations. By M. Vico, D'AZYя. This Memoir contains two obfervations: One on a fubftance of an oval form, and full of hairs, found in the uterus or womb of an unmarried woman of fixty-five, and the other on a fingular difpofition of the veffels of the mefentery. Thefe Obfervations are both curious: the latter is particularly worthy of attention. Our Academician diffected a body in which the greatest anaftomofis, which joins the two mefenteric arteries, was abfolutely wanting. This obfervation, with others that have been made on different part of the human ftructure, fhew, that there is more or less latitude in the laws of Nature even in the formation of individuals of the fame fpecies, who may live and exercife the fame functions, with remarkable diverfities of organization in the parts that perform them. We recommend this ob

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fervation to the fpoiled children of Spinofa; and to the votaries of a blind and uniform neceffity.

Mem. III. A Defeription of a Monftrous Child, with One Head and Two Faces, and Two Bodies joined in their upper Parts, the one regular and complete in its conformation, the other imperfect. By M BORDENAUE. A woman belonging to the village of Brunoy, aged thirty-three years, after a labour of three days, was naturally delivered, the 23d of June 1775, of the Foetus, which is the fubject of this Memoir. The Foetus was prefented to the Academy of Sciences, and is reprefented at the end of the Memoir by four figures, that give a clear idea of the situation of its parts. The woman's delivery was long, though not laboious; for Nature had done the work before the arrival of the furgeon. The navel- ftring, being weak, was broken during the delivery, and the child died through lofs of blood and want of fuccour. On this the furgeon, turning all his attention to the affiitance of the mother, was furprifed to find a fecond child, which was male, well formed, and lived three days after its birth.

The infpection of the other Foetus, which was manifeftly a junction of two bodies, perfuaded our Academician, that there was no anomalous production in the cafe, and that the one of the two, which was a rude mass, the face excepted, and which adhered to the thorax of the other, fo as to make one substance with it, was no more than the remains of a Foetus that had not arrived at its full delopement and formation. This defect he neither attributes to the force of imagination, nor to any thing originally monstrous or anomalous in the ovum, but thinks it arole from fome cafual preffion, or fome of the various accidents to which two germs or principles of the Foetus are expofed in the time of conception. He fuppofes, that three ova or germs were impregnated, two of which, by fome accidental preffion,. contracted an unnatural union, which obftructed the progrefs of their organization, and occafioned the monftrous object here confidered; and he obferves, that thefe apparent diforders are no objections to the uniform proceedings of Nature, but are merely the effect of foreign caufes, which difconcert her operations in the period of conception.

CHEMISTRY.

Mem. I. Refearches concerning the Methods which are used by the Aflayers to fix the Standard of Gold in mixed Substances, and to determine at the fame time the Quantity of Silver they may contain, as alfo concerning the Means that may be employed to improve this double Operation. By M. TILLET. In feveral Memoirs prelented to the Academy (in the years 1760, 1762, 3, and 9,) this laborious chemist had laid down a method of feparating pertec from imperfect metals; and here, to finish his plan, he points out the

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