following the opinion of Dr; Franklin, maintained the fuperior merit and efficacy of those which were more elevated, and pointed: this opinion was followed in the conductors fixed on the powder-magazines at Purfleet: and the memoir now before us, contains a confiderable number of experiments, that confirm it in the ftrongest manner. The refult of these experiments may be contained in the following propofitions: -That it is erroneously afferted, that the pointed conductors draw the lightning fooner from the clouds, than thofe whofe extremities are blunt, obtufe, and prefent a fort of a round knob-for the contrary happens in fact:that this error arifes from confounding the property of filently drawing fire from the clouds, with that of exciting lightning, two things which are very different, as M. Le Roy abundantly proves, in this memoir-that the conductors being defigned, by their form, to draw the fulminating matter from all the parts of the building on which they are erected, ought, for that reafon, to be pointed, and to be raised to a certain height above the building :-and that, finally, fhould an explosion of lightning fall upon these conductors, its effects would be much lefs violent, than if it fell upon the others.

ANATOMY.

MEMOIR I. Obfervations on the Situation of the Liver, in its natural State, together with Remarks on the Manner of perceiving feveral of its Disorders by the Touch. PORTAL.

By M.

In order to acquire, by the touch, a certain knowledge of the diforders of the liver, it is neceffary to afcertain, by a series of obfervations, its fituation, which differs according to the age and attitudes of the patient, and which is alfo modified by feveral maladies, which do not immediately affect the gland itself. The liver is larger in the foetus than in children newly born. The ftomach of the former, which was perpendicular, becomes gradually almoft horizontal: the left lobe of the liver, when deprived of the blood, which was conveyed thither by the umbilical vein, diminishes confiderably in fize: M. Portal obferves farther, that this is not the only change occafioned by the revolution, which takes place in the circulation of the blood at the period of birth: the pelvis affumes gradually another form, the lower extremities, which receive a greater quantity of blood, grow in length, and acquire a new degree of ftrength and confitence. The form of the bafon in the foetus, and the fmallness of the lower extremities, are favourable to delivery: the child in the firft period of life, when its weakness will allow it nothing beyond a kind of reptile motion, is fo conftituted, as to go on hands and feet; but as foon as the legs acquire trength, fufficient to fupport the body in an erect posture, their

proportion,

proportion, and that of the thighs change; and all thefe changes, which are the neceffary confequences of a change of circulation, seem evidently to have been prepared and combined by the Author of Nature for the advantage of the human frame. The growth of the liver is not proportionable to that of the other parts of the body. In perfons who have arrived at a mature age, it lies entirely concealed under the spurious or baftard ribs, when they are placed in a horizontal fituation. When they are in a different or erect position, the liver becomes perceivable, and this is therefore the fituation that must be preferred, as the moft adapted to exhibit, to the touch, the true ftate of that gland.

The liver acquires a monftrous volume by the exceffive use of food, as appears from the experiments that have been made on animals. Stoppages, or obftructions in the lungs, change the fituation of the liver, which, in thefe circumstances, extends itself under the ribs; but we muft not, according to Mr. Portal, conclude from hence, that the liver is attacked: this is an error, into which he acknowledges that he has fometimes fallen, but the diffection of bodies undeceived him.

The liver, fays our Author, is not the only part of the body that changes its fituation in different attitudes. M. PORTAL obferves, that the anterior part of the bladder, in a man who Rands upright, correfponds with the fame parts of the abdomen, to which the bottom of the bladder correfponds in a man who lies in a horizontal posture. This remark may be of confiderable ufe and importance in medical practice. Such is the refult of M. PORTAL's memoir, to which we refer the Reader for farther details and illuftrations, relative to this interefting object of anatomical inveftigation, which he will find here very amply and accurately defcribed and confidered. MEMOIR II. Concerning an extraordinary Pregnancy. By M. HALLER.

This memoir contains the hiftory of a woman, who, after having discovered all the fymptoms of pregnancy, which the reckoned from the beginning of the month of June 1763, fell into a state of infirmity and languor, in which all these fymptoms totally disappeared. She recovered her health in the month of May 1764: and fhe exhibited no marks of weakness or indifpofition until July 1772.-She died in Auguft, that year, after a violent fever, which lafted feven days, and was accompanied with intense pains. On opening the body, a kind of fack or tumour was found, which communicated with the uterus by the ilium on the right, and a part of the os facrum. This fack, which had within it the right tube and ovaria, contained a fœtus of feven months, whofe putrefaction had occafioned the death of the woman; however, the circumftantial

account

account which is here given of her diforder and pregnancy, proves evidently, that the foetus had been without life from the month of January 1764. Notwithstanding this, the woman enjoyed a perfect ftate of health during eight years, with this lifeless mafs in her body, and barrennefs feemed to be the only effect it produced in the animal economy. M. HALLER mentions it as a circumftance worthy of notice, that after having fuffered pains that feemed to indicate a miscarriage, in January 1764, which may be confidered as the time of the death of the foetus; the woman fuffered again pains of a like nature, at the period which, according to the proper calculations, would have brought on the delivery; he obferves farther, that at this period fhe had milk, which was, indeed, foon diffipated, but returned two months after. MEMOIR III. Concerning a new Method of performing the Am putation of the Extremities. By M. PORTAL.

This memoir is defigned to prevent the inconveniencies that arife frequently from the ordinary method of amputation, after which a part of the bone ftill remains jutting out. This not only renders often a new operation neceffary, but also makes the cure difficult, expofes to dangerous accidents, and even after the cure is finished, prevents the ftump from being covered with flesh, which is attended with feveral difagreeable circumftances. We fhall not enter into a particular analyfis of this memoir, which might be obfcure without the amiftance of the cuts that accompany it. We fhall only mention the fact upon which M. PORTAL founds his new method, and fhew, in a few words, in what this method effentially confifts. The fact is, that the foft parts of the human body are almost all fufceptible of contraction, after being cut; and this, though in a fmaller degree, is obfervable, even in dead bodies. This contraction, or rather contractibility, is different in different parts of the human frame: it is strong and intenfe in the fkin, the adipofe membrane, the tendons, the aponeuroses of muscles, in the veins and arteries; and its moft powerful effect is produced in the moment of the feparation of the parts, though even after this feparation, it remains in activity for a confiderable time. It muft, confequently, happen after the amputation of a member, that the foft parts, fhrinking in, leave the bone uncovered; and that the different parts, fuffering a greater or lefs contraction, the wound affumes a pyramidal form, which renders the dreffing more embarraffing, and the cicatrization more difficult.

If therefore (to come to what M. PORTAL propofes) the muscle be cut in the moment of its greatest contraction, it will fhrink less than if the amputation had been made at the time of its greatest dilatation or extenfion, and a more confiderable part

of

of the muscle will remain after the amputation, than if the operation had been performed when the mufcle was contracted. It is, however, to be remarked, that of the muscles which are placed on the two fides of the bone, thofe, on one fide, are contracted when the member is ftretched out, and dilated or diftended when the member is bent or folded; while thofe, on the other fide, are diftended when the member is ftretched out, and contracted when it is folded or bent inward :-the confequence deducible from this, is, that the member muft be ftretched out during the amputation of the former, and folded, contracted, or bent inward, during that of the latter. IV. A SECOND MEMOIR Relative to the Anatomy of Birds. By M. VICQ-D'AZYR.

In the first memoir, this ingenious Academician, who has formed a high idea of the importance of the anatomical obfervations that may be yet made upon the ftructure of birds, laid down the plan, which he continues to execute, fixed the genera or claffes that form the bafis of his researches, indicated the new nomenclature, which he employs in his defcriptions, and divided into twenty-four regions, the different parts of the body of a bird. In the first memoir, he defcribed the anterior thoracic region, the region of the clavicle or collar-bone, and that of the shoulder-blade. In the fecond memoir, now before us, he examines the state of eleven regions, viz. the higher region of the fhoulder, the internal and external regions of the humerus, the internal and external regions of the cubitus, or that part which fupplies the places of a fore-arm and hand, the fuperior region of the back and neck, the inferior region of the neck, the fuperior and lateral regions of the cranium or fkull, the inferior region of the head, and that of the furface of the fkin. Ten regions more are to be exhibited and described in a following memoir. The details contained in this memoir are certainly curious and interefting; and the mechanifm, that produces the various motions of the winged tribe, is difplayed with great perfpicuity. It is more efpecially worthy of obfervation, that in comparing the mufcles and bones of birds, with thofe of the human fpecies, the analogies are found to be much greater, and more ftriking, than could have been expected confidering the little refemblance there is between the external forms of these two claffes. This fhews the beautiful uniformity that reigns in the great fcheme of nature, and that in orders of Being fo different: it is also a remarkable proof of final caufes, when we confider, that the diverfities in this otherwife uniform plan, are exactly fuited to the nature, ftructure, and motions, that characterise each class.

CHYMISTRY.

CHYMISTRY.

MEMOIR I. New Obfervations on the Analyfts of Cryftals of Verdegrije and Salt of Lead, relative to the Air that is combined in thefe two Mixts, and confidered as one of their conftituent Principles,-as alfo on a Copper and Saline Sublimate, which the Verdegrife yields in a certain Period of the Analyfis. By M. DE LASSONE.

The operation, by which the acetous fpirit, called Radical Vinegar, is obtained by diftilling verdegrife, or crystals of verdegrife, has been often repeated; but the phenomena which accompany this operation, have not, in the judgment of M. Dɛ LASSONE, attracted fufficiently the attention of chymical obfervers. He had formed the defign of afcertaining the following fact, that during the diftillation of cryftals of verdegrife, and falt of lead, a fluid efcapes, of the nature of those which the ancient chymifts called Gas, and to which the moderns give more commonly the appellation of Air; but as there efcaped alfo, towards the end of the operation, acid vapours under a vifible. form, it became neceffary to examine the refult of his diftillation, before the moment in which thefe vapours begin to appear. When M. DE LASSONE Compared the weight of the produc and refiduum of the diftillation, with the weight of the verdegrife that was employed in this experiment, he found that the latter was confiderably diminished, and that confequently a proportionable quantity of Gas had efcaped, or difengaged itself in the operation.

By interrupting thus the diftillation at a certain period, our Academician obferved circumftantially and fully a fingular fact, which had been perceived before by fome chymifts, but in a curfory manner. The neck of the retort, employed in diftilling the crystals of verdegrife, contained a folid, light, and white fubftance, which affumed a yellowish colour when it was expofed to the air. This fubftance, on examination, appears to be a copperifh, volatile falt, entirely diffolvable in water;if the diftillation be continued, the acid vapours, highly concentrated, which pass towards the end of the operation, diffolve this falt and carry it along with them; and of confequence, the copperish flowers are only to be obtained, when the diftillation is fufpended, the moment before the acid concentrated vapours appear under a white form.-Before this period of the operation, the radical vinegar contains no copper; it only begins to contain fome, when the copperifh flowers, carried along by the acid vapours, mix themfelves with this vinegar: if it is then rectified by a new diftillation, thefe flowers are no more fublimed, and therefore, a radical vinegar, exempt from copper, may be extracted from verdegrife: however, the radical vinegar, obtained by this procefs, cannot be looked upon as abfolutely