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degree on Reaumur's fcale; but rofe again, as before, when this impulfe of the air was removed. The Academician alfo found that the degrees of heat were different in water boiling in different veffels at the fame time, and in the fame fand-bath; and that its heat was greater in proportion to the intenfity of that which the veffel containing it had received from the fire previous to its ebullition; but when once in this ftate, its diftance from the fire, if not fo great as to interrupt the boiling, produced no alteration in this refpect. It also appeared that, cæteris pe ribus, water acquired heat more flowly, and was longer in coming to a state of ebullition, in proportion as the mouth of the veffel expofed a greater furface of the fluid contained in it to the external air; and that, when the latter was excluded, the heat of boiling water was the fame, of whatever materials the veffels that contained it might be made.

Mem. II. Experiments made to afcertain whether any regular proportion prevails, between the times required for the cooling of heated bodies, and the denfities of the air in contact with them; alji. whether there is any juch proportion between the fucceffive periods of time, in which a heated body, while cooling, parts with equal degrees of heat; and lafly, to determine the influence of the temperature of the air, with respect to the time in which heated bodies, in contact with it, lofe their acquired heat. By the fame. These experiments were very ingeniously contrived, and M. ACHARD has here given, in two tables, the refults of above thirteen hundred trials; but, though these were made with the utmost attention, he acknowleges that no fuch regular proportions as he had expected, are deducible from them.

Mem. III. Experiments to afcertain the effects produced on at mospheric air, and on the feveral factitious airs, by the operation of flacking quick lime in them. By the fame. Fixed air was entirely abforbed by this process, which had no effect at all on common, dephlogisticated, inflammable, and nitrous, air.

Mem. IV. Concerning Aneurisms. By M. WALTER. This ingenious anatomift here gives a minute defcription of the ftructure of the arteries, together with a concife hiftory of the dreadful diforder to which they are liable, accompanied with an account of four extraordinary cafes, illuftrated with plates, in which the difeafed parts are reprefented. M. WALTER obferves that he has never yet feen an inftance of an aneurism of the femoral artery, in which the branches, that form a communication between this and the collateral veffels, could be fufficiently dilated to carry on the circulation; but the reader will find a very curious cafe of this nature in the London Medical Journal, vol. VIII. in which, a true aneurism of the femoral artery, occafioned by a wound received very near it, was cured by compreffion; and, though the cavity of the artery was entirely obli

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terated,

ated, and all the symptoms of intercepted circulation ensued, tthefe foon diminished, and the patient was completely revered, and able to follow the daily labour of a husbandman ithout any inconvenience, except an obtufe fenfe of torpor in e leg, and a little cedematous fwelling of it after long ftandg; which, however, always went off after lying a few hours bed.

Mem. V. On the Difeafes of the Heart. By the fame. Under is title, M. WALTER Comprehends all thofe disorders, which lay fo affect the motion of the heart, as to stop or impede the irculation of the blood; and confiders thofe accidental cirumftances in the fize and conformation of this vifcus, by which hey may be produced. He obferves, that, in tall robuft perons, it has fometimes been found remarkably fmall; and, on the ontrary, very large, in perfons of less than the common ftature nd ftrength. Its fize, however, is of little confequence, provided the greater blood-veffels, as the aorta, the pulmonary veins and artery, have a due proportion to each other, but he fays he has generally found that, in fmall hearts, there is lefs fat than in shofe of a greater fize; that the mufcular fibres are relaxed, and confequently the ventricles rather too large, in proportion to the fize of the heart. Hence perfons of this description have generally a very rapid pulfe, and are fubject to faintings and palpitations. M. WALTER informs us, that he has feen two instances, in which the human heart was as large as that of an ox: the first was that of a man, of small ftature and of no extraordinary ftrength, who died of a marafmus at a very advanced age: the greater blood-veffels were well proportioned to each other. The fecond inftance was the heart of a very tall robuft mah of forty years of age, who had, during many years, been troubled with anxiety and palpitations, and fuffered extremely from them for fome days before his death; which was occafioned by an apoplexy. On diffection, the abdominal vifcera were found in a healthy ftate; but the lungs were filled with extravafated blood, and adhered to the pleura, though the thorax was remarkably large the cavity of the aorta, in the part whence the left carotid and fubclavian arteries branch off, was remarkably contracted, and that of the pulmonary artery greatly dilated. The anatomift alfo gives fome inftances, where nature has varied from her ufual forms, with refpect to the rife and courfe of the greater blood-veffels; but for the particulars of thefe, we muft refer to the memoir and the plates by which it is illuftrated. Sometimes, M. WALTER obferves, diforders are occafioned by offifications in the pericardium, or by too great a vifcidity of the fluid which it contains; fometimes, there are tumours on the heart itself; he gives an inftance of a fteatoma on the apex of that of a girl, who died of an apoplectic fit, and of a meliceris U u 4

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on the heart of an ox. Laftly, they may be derived from inflammation, either of the heart, or the pericardium: this is exemplified in the cafe of a middle-aged man, whofe pericardium was highly inflamed and filled with pus, which had not only corroded the surface of the heart, but penetrated into its mul

cular fibres.

Mem. VI. On the degrees of heat, which folutions of differents falts acquire in ebullition. By M. ACHARD. We have here the refults of eighteen experiments, of which the following are the moft important-common falt, when either decrepitated, or regenerated, thrown into boiling water, increafed its heat in pro portion to the quantity of falt diffolved; but, when not decre pitated, it had an oppofite effect.-Glauber's falt, fedative falts, vitriolated tartar, prifmatic nitre, also increased the heat acquired by the water, but in a lefs degree than decrepitated common falt, and, fome of them, to no determinate point.-Sal ammoniacum, when only three drachms were added, diminished the heat of the water; but larger quantities ferved to increase it in a greater proportion than the decrepitated common fait-Calcined borax, Epfom falts, and felenite, diminished the hear, but in no regular proportion.-Vitriol of copper, and alium, did not alter it; but white vitriol and fugar of lead produced a diminution of heat, which continued to be the fame, whatever quantity of these falts was added to the water; that produced by the fugar of lead, was the moft confiderable.

Mem. VII. Experiments made to investigate the proportion of the increase of a given volume of water, to the quantity of falts diffolved in it. By the tame. It has been afferted by many, that, when a faline fubftance is diffolved in water, the volume of the folu tion is lefs than the volume of the water, added to that of the falt before its being melted. Hence they maintain that a part of the falt, thus diffolved, is lodged in the interftices between the particles of the water, which will not increase in volume, till thefe are filled up. This opinion appearing doubtful, the indefatigable Academician was induced to examine it; and, by means of an apparatus ingeniously contrived, but not eafily defcribed without a plate,. he performed a confiderable number of experi ments, for this purpofe; by which it appears that, of Sal ammsniacum and of falt of tartar, fome part does infinuate itself into the pores of the water, without enlarging its bulk: yet that, in the folution of all other falts, the volume is increased in proportion to the quantity diffolved. This increafe was always more confiderable after, than before, the faturation of the water; except when the experiment was made with fedative falt, in which cafe, this circumftance made no difference refpecting the proportion in which the volume is increased.

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Mem. VIII. Meteorological Obfervations_made at Berlin, in the year 1785. By M. DE BEGUELIN. For thefe, we muft refer the curious reader to the volume.

MATHEMATICS.

Mem. I. Aftronomical and critical inquiries concerning the longitude of feveral places in India. Part I. By M. JEAN BERNOULLI. In preparing for the prefs an hiftorical and geographical defcription of India, this ingenious writer met with feveral circumftances that well deferve to be inveftigated; fome of which fall within his peculiar province as an aftronomer. Thofe, which he proposes to confider in thefe memoirs, relate to Mr. Rennel's new map of Hindoftan, who has made the distance between the mouths of the Indus and the Ganges, two degrees and a quarter II greater, and the breadth of the fouthern part of the peninfula, three quarters of a degree lefs, than former geographers. To afcertain whether Mr. Rennel be right in the latter of these alterations, M. BERNOULLI propofes, in this part of his memoir, to inveftigate the longitude of Goa, on the western coaft, in about fifteen degrees of latitude; for, he obferves, the longitude of that part of the eastern coaft, under the fame parallel, is pretty well known from the obfervations taken at Madras and Pondichery. For this purpose, he gives the obfervations on an eclipse of the moon, Dec. 21, 1684, taken, at Goa, by Father NOEL, a Jefuit; from which, compared with his own, at Paris, M. CASINI calculated the longitude of Goa to be 71° 25′ weft from Paris this refult was adopted by the Academy of Sciences, and by M. D'ANVILLE, in his map. But, according to Father NOEL's account, the beginning of the eclipfe was not diftinctly obferved; for this reafon, M. BERNOULLI, by comparing this with other obfervations, has endeavoured to rectify any error, which might arife from that circumftance; but cannot make the longitude of Goa amount to more than 71° 26' from Paris, and therefore 75° 46′ from Greenwich; and, by the mean refult of his calculations, Goa is only 78° 8' from the former, and 73° 28′ from the latter meridian. Confequently, according to M. BERNOULLI, our English geographer, who makes it 74° 15' eaft from Greenwich, has committed an error of halt, or, more probably, of three quarters of a degree, and is wrong in thus diminishing the breadth of the peninfula. But, before the Academician prefumes to decide this point, he propofes to examine, in the fecond part of this memoir, the results of obfervations made at Goa, Rome, and Leipfic, on a lunar eclipfe in the year 1707.

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Mem. II. Concerning an univerfal manner of integrating equations with partial differences of the first degree, when thefe are linear. By M. LE GRANGE. The method is very fhort and easy, and

peculiarly

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peculiarly applicable to the calculation of trajectories, and to other problems in higher geometry.

Mem. III. Concerning the elements of the folar orbit, in which the apogee, mean longitude, and greatest equation, are ascertained from new ob/ervations. By M. DE LAMBRE. The observations here mentioned, are thofe of Dr. MASKELYNE, on which, from their number, the excellence of the inftruments with which they were taken, together with the known accuracy and abilities of the obferver, M. DE LAMBRE thinks, we may rely with the utmoft confidence.

"[To be continued] Sow,

ART. XXII.

De l'Application de l'Electricité à la Phyfique et à la Medicine: i.e. Differtation on the Application of Electricity to Physics and Medicine; to which the Prize was affigned by the ROYAL AND PATRIOTIC SOCIETY of Valence in Dauphiné, by A. PAETS VAN TROOSTWYK, Member of the Philofophical Societies of Haarlem, Rotterdam, and Utrecht, and C. R. T. KRAYENHOFF, M. D. Member of the Philofophical Society of Utretcht. 4to. Amfterdam. 1788.

WE

E are informed, in the preface, that this differtation (originally written in Latin) was tranflated into French by the ingenious and learned Profeffor VAN SWINDEN of Amfterdam, and that it is now published in this language at the defire of the fociety for which it was written. The queftion, which gave occafion to it, was propofed in the following terms: Has artificial electriciry, from its difcovery to the prefent time, really contributed to the progress of phyfics? And has it, confidered in a medical view, been of more fervice than prejudice to mankind? It can fcarcely be fuppofed that fuch a queftion could admit of a negative; nor can we imagine that it was propofed as a matter of doubt. We must therefore conclude that this learned body wifhed to facilitate the ftudy of electricity, by means of a general, hiftorical, and critical, view of the feveral discoveries that have hitherto been made in this branch of phyfics,-of the meteorological theories to which they have given occafion, and of the various experiments in which electricity has been applied to the cure of difeafes. If this was the intention of the Society, it is completely anfwered by the work before us; which contains a very ample account of what has been done in these refpects, by philofophical and medical electricians, interfperfed with judicious obfervations on facts and opinions.

The Differtation is divided into two parts: in the former of which, the phyfical, and, in the latter, the medical, application of electricity are diftinctly confidered. In the first part, the authors give an hiftorical view of the gradual progrefs of electrical knowlege from the earlicft difcoveries down to the year 1786,

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