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haps more enticing though lefs lucrative, offer was made him by the king of Pruffia. That illuftrious philofopher, and patron of philofophers, invited D'Alembert to meet him at Wafel after the peace of 1763, and, on the first interview, affectionately embraced him. The king's first question was, "Do the mathematics furnish any method of calculating political probabilities ?" To which the geometrician replied, "that he was not acquainted with any me thod of this kind, but that if any fuch exifted, it could be of no use to a hero, who could conquer against all probability." The king, who would, doubtless, be gratified by fuch a compliment, and who was already well acquainted with the talents of D'Alembert, made him an offer of the prefidency of the academy of Berlin, vacant by the death of Maupertuis. The ferment which had lately been excited in France by fome articles in the Encyclopædia, especially that of Geneva, and the odium which had particularly fallen upon himfelf, might have furnished a good reafon for feeking a peaceful afylum in the court of a philofophical prince. D'Alembert, however, chose to decline the offer; and the king, far from being difpleafed at the refufal, maintained a friendly correfpondence with him as long as he lived. The letters which paffed between them will be found in "The Pofthumous Works of the King of Pruffia," This correfpondence, together with that which he carried on with Voltaire and other philofophers; the conftant intercourse which he had with illuftrious perfons at home, and with learned foreigners; his influence in the academy of fciences, and, above all, in the French academy, of which, after the death of Duclos in 1772, he was fecretary, were circumftances which concurred to give import ance to the character which D'Alembert, during the latter part of his life, fuftained in the republic of letters. And, though his ene mies called him the Mazarin of literature, candour requires us to believe, that he owed his influence lefs to artful management and fupple address, than to the esteem which his talents and virtues inspired, His averfion to fuperftition and priest-craft carried him, it is true, into the region of infidelity; and his enmity to the Jefuits and the clergy produced in him a degree of hoftility against the re» ligion of his country, which fometimes obliged even the philofopher Frederic to read him a leffon of moderation. The eccentricity of his opinions did not, however, deftroy the virtues of his heart. A love of truth, and a zeal for the progrefs of fcience and freedom formed the basis of his character; ftrict probity, a noble difintereft, ednefs, and an habitual defire of obliging were its diftinguishing features. Many young people, who difcovered talents for science and learning, found in him a patron and guide. To worthy men, even in adverfity and perfecution, he was a firm and courageous friend. To those who had shown him kindness, he never ceafed to be grateful, P. 149,

We shall take an early opportunity of refuming our review

of this work; and, in the nrean time, we recommend it to the attention of fuch as are defirous of perusing faithful accounts of thofe who

fui memores alios fecere merendo.

Tranfactions of the Royal Society of Edinburgh. Vol. IV. 4to. I/. IS. Boards. Cadell and Davies. 1798.

A change in the future conduct of this publication is announced in the volume before us; a change which, compared with the diminished bulk of the prefent volume, leads us to fear a relaxation in the fpirit or the induftry of the members, though fome perhaps may draw a different conclufion. It is determined, that the publication fhall be annual, whether there are papers fufficient to form a volume or a part only.'

The arrangement of thefe Tranfactions must be well known. The hiftory' is a journal of the bufinefs of each meeting, with an abftract of fome of the papers, which for different reafons are not immediately published. The firft paper thus fhortly noticed is Mr. Fisher's eafy and general method of folving all the cafes of plane and fpherical triangles. This gentleman has greatly improved and fimplified both Napier's rules and Pingre's more concife forms of them, including the whole in four theorems, which comprise the rule not reducible to Napier's theory of circular parts, viz. where the three fides, or the three angles of the triangle, are given. Thefe rules we will tranfcribe: they are applicable both to plane and spherical triangles.

1. M denotes the middle part of the triangle, and must always be affumed betwixt two given parts. It is either a fide or the fupplement of an angle.

2. A and a are the two parts adjacent to the middle, and of a different denomination from it.

3. O and o denote the two parts oppofite to the adjacent parts, and of the fame denomination with the middle part.

· 4. 1 is the laft or moft diftant part, and of a different denomination from the middle part.

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Mr. Fifher recommends, for the purpose of remembering these rules, to commit to memory the words Sao, Satom, Tao, Sarfalm, formed from the abbreviation of the terms of the above proportions. It is obvious that these four theorems apply to plane triangles, providing that, instead of the fine or tangent of a fide, you take the fide itfelf." P. 5.

The next abstract relates to Dr. Hutton's Effay on Light and Heat, a work not much efteemed. The principle, that light and heat are the fame elements, is certainly erroneous, and the theory of courfe untenable.

The refult of Dr. Balfour's obfervations on the barometer at Calcutta, where the inftrument is more fteady, and its range lefs extenfive than in Europe, are interefting. He obferved the column of mercury every half hour, for one entire lunation.

The refult was, the discovery of a periodical variation in the barometer, confifting of two ofcillations, which it performs regularly every twenty-four hours.

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1. On every day, that Dr. Balfour obferved, with scarce any exception, the barometer conftantly fell between ten at night and fix in the morning; and this it did progreffively, without any intermediate rifing but in one inftance.

2. Between fix and ten in the morning the barometer conftantly rofe; it alfo did fo progreffively, and rarely with any intermediate falling.

3. Between ten in the morning and fix at night the barometer fell progreffively, without a fingle exception.

" 4. Laftly, between fix and ten at night the barometer rose progreffively, without any intermediate falling, except in one inftance.' P. 23.

It is proper to remark here, that fome obfervations of a fimilar fort have been made in Europe; where, though the fituation is far. lefs favourable, than in India, for difcovering the true law of fuch minute variations, refults have been obtained tolerably confiftent with one another, yet differing confiderably from thofe that are ftated above.

A series of fuch obfervations was inftituted by M. Planer of Erfort in Germany, and is defcribed in the Ephemerides of the Me

teorological Society at Manheim for 1783. Before these observa tions, it had been remarked, that when the barometer is rising, it ftands lower at noon than at any other time of the day, and higher at the fame hour when it is defcending. M. Planer's observations seem to extend and modify this conclufion; for they make it appear, that between ten and two, both of the day and night, that is, for two hours before, and two hours after the fun is on the meridian, the elevations and depreffions of the mercury are less than at any other time of the day; and that between fix and ten in the morn ing, and, again, between fix and ten at night, these elevations and depreffions are the greateft. The fame rule feems to be confirmed by the obfervations of M. Cotte in France, of which he has given an account in the Journal de Phyfique for 1792 and 1794.' P. 25.

An abftract of another paper by Dr. Hutton is added, relating to the light produced from melted fulphur, and from iron brought to a malleable state. This gentleman finds confiderable difficulty in explaining the phænomena, which might have been eafily avoided, by confidering light and heat as feparate elements. In thefe inftances, the light feparates more copiously, while the heat leffens.

Accounts of the deceafed members follow: they resemble the Eloges of the French academy. The maxim of the Cale donian biographer is nil nifi bonum; that of the French nil nifi optimum. The life of lord Abercromby, one of the fenators of the college of justice, brother of the two generals, is written with great fpirit and warm affection. That of Mr. Tytler fucceeds. This gentleman, who publifhed feveral elegant treatifes refpecting ancient literature, is chiefly known in this kingdom as an author, by his defence of the unfortunate Mary, which gave a different direction to the opinion of hiftorians on this fubject. This is the work which has been so unmercifully pillaged by Mr. Whitaker, and wire-drawn to three flimfy octavos.

Mr. William Hamilton and Dr. Roebuck were little known as authors. The former was profeffor of anatomy and botany at Glasgow, an able and ingenious anatomift as well as a ju dicious practitioner in phyfic and furgery. The fecond is chiefly known as a man of great abilities in conftructing fur naces and machines, and applying them to different purposes of chemistry and metallurgy. He was the most active pro jector of the Carron iron works; but afterwards, like other projectors, funk the fruits of a life of labour in a failing speculation upon coal works.

The firft paper in the phyfical clafs is the Account of a Mineral from Strontian, and of a peculiar Species of Earth which it contains, by Thomas Charles Hope, M. D.' The fubfiance of this paper was given in the Hiftory' of the laft

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volume, feemingly with a view of anticipating other analyfes, and claiming the firft honour of the difcovery. Be this as it may, the nature of the Strontites is now well understood; and we need not enlarge on the article before us, in which its chemical hiftory is detailed with great minutenefs and apparent accuracy. Some remarks on the carbonate of barytes are added, chiefly to prove that the carbonic acid may be feparated by heat alone.

II. Obfervations on the Natural History of Guiana. By William Lochead, Efq.'

Every thing relating to that country is curious; but, in this paper, we muft diftinguish the obferver from the philofopher. In the former character, Mr. Lochead is refpectable; in the latter, he has not attained a high rank.

The pofition and extent of Guiana wè have lately had occafion to notice. The muddy water, at the diftance of many leagues, and the rolling waves, infeparable from a flat coaft, are defcribed too minutely. The appearance of the tropical. fky, mentioned by many travellers, is not fatisfactorily accounted for; and, from the long defcription of the feafons, we can collect only that the fecond rainy feafon preferves Guiana from hurricanes; in other words, the rain of that period filently and effectually reftores the æquilibrium of the electrical fluid.

The country near the fea has been repeatedly defcribed; but the more elevated parts are less knows. From this account we shall select à part; but muft hint, that we fufpect the writer of having mistaken the stone defcribed as granite.

Continuing to afcend the river, the fand-hills become rather more frequent, but the intervals ftill remain a perfect flat, though now feveral feet above the level of the stream, and the foil is still a ftiff clay. Hitherto the river is deep all over, generally from two to five fathoms; the bottom is mud or clay, and the shores on either fide at low water covered with ooze. About 130 miles up,

however, or just before it begins to fhallow, the bottom is covered with banks of a hard white or brown fand. It was a problem for fome time whence all this fand originated in fuch a country. It was foon folved. Leaving here the veffel that had hitherto carried us, we proceeded in a canoe; and at about 160 or 170 miles diftance from the mouth of the river, we met with the firft proper hills of folid materials. The nearest to us was a rock of granite projecting into the stream, whofe direction it gave a change to at this place, and it ferved for a landing-place to the highest piece of cleared land upon the river next to the poft-holders. It was part of a low ridge of the fame ftone which croffed the country, probably to Berbia or beyond it, and was fucceeded by many other series of hills more inland, and as far as we could examine them, of the fame

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