From thefe confiderations Mr. Cadet is induced to confider borax as formed by the earth, partly coppery, which exifts in a feparate ftate in the natural borax, (borax brut,) and by the marine alkali. In that cafe the fedative falt will be a combination of this earth with the acid employed to decompofe borax, and, confequently, thofe who wish to perfect the analysis of borax, or to fupply its place in the arts by other fubftances, fhould apply themselves to know this earth.

ASTRONOMY.

Application of Analysis to Geometry: By Mr. Du Sejour.

The object of this paper is to apply to the obfervations of the eclipfe of the fun of the first of April, 1764, the methods which Mr. Du Sejour has presented to the Academy in 14 memoires written fince the year 1769. He enters into a very accurate inveftigation of near 80 obfervations of this eclipfe (which he hopes will turn out one of the most interefting aftronomical events of this century), and as the best of thefe agree in giving the fame values for the elements which the obfervations of eclipfes may ferve to determine, that is, the fame correction to be made in the elements known by a very near manner; no doubt can be entertained, either of the goodness of the obfervations, or the exactness of the elements corrected after them.

Mr Du Sejour had thought that fome doubts were to be entertained about the exactness of the horary movements of Clairault's tables; thefe doubts have been confirmed by a more accurate inveftigation, and he thinks himself obliged to adopt thofe of Mayer's tables.

The obfervations of the eclipfe of 1764 gave the diameter of the fun fmaller than the beft aftronomical tables fuppofe it; the difference is about three feconds and a half on a femi-diameter. There muft, there

fore,

fore, either have been inaccurate inftruments used in this measurement, or fome optical illufion muft encrease the fenfible diameter. The diameter of the moon likewife, as given by the tables, does not agree with the duration of the total, and that of the annular eclipfe. This difference may be explained by fuppofing that the folar rays undergo an inflexion in going near the moon, which inflexion Mr. D. S. attributes to their paffing through the atmosphere of the moon; this difference is only of about three seconds and a half for the femi-diameter.

Mr. D. S. had fuppofed this quantity larger by a fecond, as well as the diminution of the fun's diameter; but his new enquiries have led him to this conclufion, which he is more fatisfied with, as it agrees with the obfervations of Meff. Mechain and Lexell, who have separately found the fame thing.

Mr. Du Sejour is about to publish in one work the feveral methods of analysis which are difperfed in his feveral memoires.

On the Obliquity of the Ecliptic: By Mr. de Lalande. Mr. de Lalande having found the greateft number of his obfervations of the value of the diminution of the ecliptic give him 35 feconds for each century, he thinks he may-confider this value as exact,-deduce the mean denfity of Venus from it,-and correct accordingly, the elements on which the value of this density may have an influence, fuch as the law of the preceffion of the equinoxes, and the quantity of the nutation of the axis of the earth.

On the Obliquity of the Ecliptic: By Mr. Caffini de Thury.

Mr. C. de Thury remarks on some of Mr. de Lalande's arguments, and confiders his conclufion about the quantity of the variation as far from being founded in truth.

On

On Aftronomical Refractions: By Mr. le Monnier.

Mr. Le Monnier, who has long been engaged in this purfuit, gives fome obfervations which fhew that there is an encreafe of refraction occafioned by the cooling of the atmosphere.

On the Determination of the Orbits of Comets: By Mr. de la Place

This is a method for determining the orbits of comets, by more than three obfervations.

Account of Comets obferved in 1786; By Mr. Meffier.

GEOGRAPHY.

On the Pofitions of Alep and Diarbekir By Mr. Le Meunier.

Storia di Ecelini di Giambattista Verci. Baffano 1779; 3 vols. 8vo. A copy to be had of Elmfly.

T

HIS is one of the books which must obtain

a place in every complete hiftorical library, not from any very fingular merit, either in the history or execution, though the latter is as good as it could well be on fuch a fubject; but because the hiftorical column would not be complete without it. Probably, however, the hiftory of the tyrant of Padua has never been fo accurately told as it is here, owing to a great number of authentic documents collected from the different libraries in Italy, and which coinpofe the whole of the third volume. From thefe it appears, that the famous tyrant, however black he was, and however atrocious his acts of cruelty were, efpecially in the latter parts of his life; ftill he was neither fo early, nor

fo

fo thoroughly abandoned as he has been reprefented to be, by thofe of the Gibelline faction, who, having gained the afcendant in Italy, reprefented all thofe who were attached to the Emperors in the most odious colours they could find.

Opere dell' Abate SAVERIO BETTINELLI., 5 Vol. 8vo. [One copy to be had of Elmfly.]

HIS is an ingenious writer, who will be read

TH

with amusement and inftruction by those who are fond of Italian literature; though there is little, in his works but what may be drawn from other fources. The second and third volume, containing the hiftory of the revival of learning, arts, and manners, from 1000 to 1500; and the differtation on Italian poetry at the beginning of the fourth, feem to be far the best parts of the work; and to thofe who do not care to wade through Tirabofchis's Storia della Litteratura Italiana, or who wish to read what he fays on the revival of letters, drawn up in a fhorter compafs, will afford great information, particularly the feveral differtations on the language-the eloquence and poetrythe mufic-fculpture, &c.-the feafts, and theatrical amufements-the knight errants-commerce-luxury and customs, which make up the fourth volume. I do not fee much either in the poetry, which is contained in vol. 5th. the philofophical reafonings on the hiftory of man, drawn from the book of Genefis, which make up the first, or the differtation on enthusiasm, in volume the fecond. There is, however, an entertaining preface to the latter, containing fome criticisms on feveral Italian works, and pointing out the corruptions that have arifen in compofition from the imitation of the French writers. Upon

the

the whole, the lovers of the Italian belles lettres will meet here with fome fenfible and acute, mixed with much defultory information.

Flora Japonica, Sistems Plantas infularum Japonicarum fecundum Syftema Sexuale Emendatum redactas ad 20 Claffes, Ordines, Genera, ei Species, cum Differentiis Specifiis, fynonymis paucis, Defcriptionibus concinnis et 39 iconibus adjectis edente CAROLO PETRO THUNBERG, Med. Do&t. Prof. Reg. Svo. *

E

XCEPT the inaccurate things to be found in Kampfer's Amanitates, and a few other scattered publications, little was hitherto known of the plants of Japan. We are, therefore, much obliged to Mr. Thunberg, who, during a ftay of fixteen months on the inland, (where he had many good opportunities of obferving, though purchased at a great expence,) has given us 22 new families, and 316 new genera. Japan has many plants in common with Europe, America, China, and the Eaft Indies. Mr. T. has diftributed all thofe he has obferved according to the fexual fyftem, only he has taken away feveral from the families, Gynandria, Monacia, Diacia, and Polygamia, and arranged them differently, according to the number of the ftamina.

From the comparison of the climate he was not furprized to find many plants common to our climate in Japan; the specific character of which he changed

*The defire of giving early information having induced me to venture this imperfect tranflation of the account of this valuable work in the Gottingen Review, I trust Botanists will not be extreme to mark any errors my imperfect knowledge of the fubject and language may have led me into.

according