for example, we put into water the compound called hepar fulphuris, the two principles of which are fulphur and fixed alkali, it will, without being decompofed, unite with the water and thus form a new compound of three principles. Now, water and fulphur alone are incapable of uniting; but the fixed alkali having a confiderable affinity as well with water as with fulphur, it acts in this cafe as an intermediate principle. Let us obierve, ⚫ that in this intermediate affinity, that of the intervening principle is weaker by being thus divided than it would have been with either of the two feparate.

3. Sometimes a third principle applied to a compound of two others, unites with one and obliges the other to quit entirely that to which it was firft united. In this cafe there is a total decompofition of the first compound, and a new combination takes place. This happens when the advening principle has a greater affinity with one of the others than fubfifts between themfelves. For inftance, if we mix an alkali with the folution of a metal in an acid, the alkali, having a much greater affinity with the acid than with the metal, feizes the acid and obliges it to quit the metal, which falls to the bottom, the latter having lefs affinity with the acid than the acid has with the alkali.

4. It happens in fome inftances, that the fame principle which through the affinity above mentioned, had been separated from another, alfo caufes in its turn the feparation of the fame principle by which it had before been precipitated. This reciprocal affinity takes place when the two principles which have alternately fparated each other, happen to poffefs an almost equal degree of affinity to the third principle, and that their feparation is occafioned by fome particular circumstance relative to fome of their properties.'

Our chemical Readers will perceive from what we have tranflated from this article, that the author, whoever he may be, is not ignorant of his fubject. We cannot, however, help obferving, that in this article, as in many others, he is unneceffarily prolix, and tautological in his manner of expreffion. The book is nevertheless by no means an useless performance.

Hiftoire des Revolutions de P Empire Romain, &c.

That is, The Hiftory of the Revolutions of the Roman Empire. By S. N. H. Linguet. 12mo. 2 vols. Paris, 1766.

Tv Wons of a HIS work is a continuation of Vertot's hiftory of the revolutions of the Roman republic, and though inferior to the masterly performance of the ingenious Abbè, has notwithftanding a very confiderable degree of merit. There is a spirit

and

and rapidity in the Author's ftyle well fuited to his fubject; his obfervations are often new, and generally juft; he appears to have read with taste and judgment the works of those celebrated ancients, who have written concerning the Roman emperors, and to have been upon his guard against that blind and often malevolent credulity which is too obfervable in almost all of them.

Those hiftorians who wrote after the reign of Tiberius, Nero, Caligula, &c. are as extravagant in their fatire, M. Linguet imagines, as their predeceffors were in their flattery of those men, whom a fatal grandeur expofed both to the one and the other. Even Tacitus himself, he thinks, is not to be excepted. His hiftory, he acknowledges, is the most perfect production of the kind, that is left us by antiquity; full of fublime strokes, which fhew a profound genius, formed for giving leffons to pofterity; but formed likewife perhaps for impofing upon it. He indulges too much in a certain fharpness and feverity which was natural to him, and which, indeed, is in fome measure pardonable in thofe, who, having lived long in the world, perfuade themselves at laft that there is nothing to be seen in it but counterfeit virtues, or disguised vices.

This difpofition, our Author fuppofes to have been as much the effect of natural temper in Tacitus, as of reflection. His make and conftitution led him more to fatire than panegyric; and the influence of conftitution upon the manner of feeing and painting objects is well known. Who knows, befides, fays our hiftorian, whether Tacitus, in following his natural inclination, did not mean to pay his court to thofe princes whom he commends, and under whofe reign he wrote? The most extravagant fatirifts are often the most artful and delicate flatterers. Who can affirm, that the implacable cenfor of Tiberius was not defirous of making what he said of the fucceffors of Auguftus contribute to his advancement under the fucceffors of Domitian ?

Whether Tacitus was influenced by fuch motives, or not, our hiftorian thinks he may be fufpected of it without any injustice. It is impoffible, we are told, to believe all that he fays in regard to the firft Cæfars. He draws fuch a horrid picture of their debaucheries, and of their refinements in cruelty, as is more dishonourable, in fome measure, to human nature itfelf, according to M. Linguet, than to those to whom they are imputed. How far thefe reflections upon Tacitus are juft, those who are acquainted with his character and writings muft determine for themfelves; that there is fome truth in them, the most fanguine of his admirers, we apprehend, will readily

allow.

Our hiftorian is no advocate for Tiberius, and it would be ftrange indeed if he were; from a perfuafion, however, that his

vices have been exaggerated by Tacitus and Suetonius, he feems defirous of fhewing that he was lefs cruel than the malignant eloquence (as he expreffes himself) of the former of these hiftorians, and the weak credulity of the latter have reprefented him. In regard to those beaftly exceffes he is faid to have been guilty of, after the death of Sejanus, when he was near seventy years of age, M. Linguet fuppofes it highly improbable that libertinifm fhould fpring up in his heart, at a time when almost every other paffion was extinguifhed, and thinks it quite incredible that the froft of old age fhould kindle fuch irregular tranfports as are feldom found in the boiling heat of youth. As he has nothing to oppose to the teftimony of Tacitus, however, but the feeming improbability of the thing; though what he advances on this head is very ingenious, and feems to proceed from a love of truth and a generous concern for the honour of human nature, yet it has certainly no great weight in it, efpecially when we confider what filthy monsters there have been, and ftill are in the human fpecies, and that Tiberius, even allowing the truth of all that M. Linguet has faid, is still a detestable wretch, and seems capable of all that Tacitus lays to his charge.

Our Author's history reaches from Auguftus to the death of Alexander Severus; an interefting period, and full of important inftruction. It prefents us with a view of the greatest republic on earth, changed by an ufurper into an immenfe monarchy. This monarchy foon degenerates into a cruel tyranny. The Romans, after having been fo long the most haughty nation of the universe, become the meaneft of flaves. At certain times, indeed, they recover fome degree of their former vigour, but they always employ it to tear their own bowels. Those once haughty conquerors, thofe intrepid defenders of their liberties, now no longer diftinguish themselves but in civil wars, and have no other object of their ambition, but the choice of a tyrant.

Such are the objects our historian presents to his readers, and he prefents them in a lively and agreeable manner. His work, indeed, confidered as a continuation of Vertot's history of the revolutions of the republic, is justly, though modeftly characterised by himself;-it is, fays he, like a flatue with its head by Phidias, and the rest of its body by one of his difciples.

De Arte Medendi apud Prifcos, Mufices ope atque Carminum, Epiftola ad Antonium Relhan, M. D. An Epifle to Anthony Relhan, M. D. on the Art of Healing by Mufic and Poetry among the Ancients. London. 8vo. 1s. Johnfton.

HE intention of this epiftle, which appears to have been written in Holland, is to prove, chiefly from the autho

TH

rity of the ancients, the great ufe of mufic in the cure of difeafes. Mufic is used by the author as a general term:

Mufice, fays he, vox generalis eft, ficut et Plutarcho videtur, qui libro fuo totam hunc artem complectenti, mg μouns infcripfit. Ejus partes funt vox, inftrumenta et carmen, five vocabula metri cujufdam legibus adftricta. Apud prifcos enim nullum fuit carmen nifi cum mufice conjunctum. He begins with the Greek phyficians, then confults their hiftorians, and afterwards quotes from their poets fuch paffages as ferve to prove his pofition. From the Greeks he comes to the Romans, among whom Cicero, Pliny, Virgil, Horace, Propertius, Tibullus, are his advocates. Having proceeded thus far, que plurima reflant, fays he, in banc rem teftimonia, fciens prætermitto, ne jactationi potius quam neceffitati, id tribuiffe videar. Nam ex iis quæ attuli, fatis patent, quas vole, conclufiones. He then calls fcripture to witness, particularly in the inftance of David's curing Saul by means of his harp. Having now done with facts, he proceeds to support his thefis from nature and philofophy. Confidering man, according to Plato, as compofed of four diftinct parts, viz. an earthy, a vegetable, an animal, and a fpiritual, he fhews how these are feparately affected by mufic. Speaking of the firft, Si vitreos calices, fays he, difrumpant moduli difcordes quamvis leniffimi, quid nervis corporum tenuiffimis, et delicatiffimis, fæminarum præcipue, exiftimandum eft? Tale quid et ipfi nervofi, ut vocitas, fentire videntur; quorum nonnulli, ingruente jam morbo, femet in vafa vitrea mutatos effe arbitrati funt.

With regard to the fecond principle of human nature, he thinks it hard that we fhould deny to vegetables that fenfibility which hath been granted to earth and tones. Senfum negas eum, quem faxis ineffe fateris? Non adeo abfurde philofopharis. Eruditos vero, præcipue focietatis veftræ Regiæ focios, iterum iterumque voco in partes, ut hanc rem tandem faceffant, nec vegetabilia finant, pulcherrimum naturæ opus, a finibus mufices diutius exulari, ubi faxis, lutoque conceditur locus.

As to the third principle, namely, our animal part, its senfibility to music is too univerfal to require any proof; neverthelefs, he thinks it not amifs to hear what the poets fay upon this fubject. We tranfcribe the following paragraph partly out of regard to our own Shakespeare, and partly to fhew what great things were expected, by ftrangers, from Dr. Johnfon's edition of that poet. Quid in re tam aperta verbis opus eft? Poetas tamen paulifper audiamus, quorum carmina in hoc loco melle dulciffimo dulciora fluunt. Equibus præcipue laudandus mihi Shakespeare veftras, tum jure fuo, tum quod ei plurimum debeo. Hujus enim accenfus amore, linguæ Anglicana primum operam dedi, donec eam et legere, et intelligere potui, quamvis nec loqui nec fcribere poffum; et nunc eum dies noclefque libentiffime legere foleo. Eundem audio bonis

avibus cito proditurum, curante Clariffimo Johnfonio; a quo fperare licet, quæ labor, ingenium, eruditio, fidefque perfeciffima editoris præftare valet. De Philologia enim optimé, nec minus de cunctis bonis artibus meruit. Quantum ejus dictionario debeo, tu ipfe fcis. Hanc certe editionem avidiffimis animis omnes in hoc loco expectamus Shakesperiani.

From thefe few examples we imagine it will be pretty evident to the learned Reader, that our Author's intentions, in regard to his pofition, are by no means ferious; but that his language is claffical and elegant.

Hiftoire des progrès de L'Esprit Humain dans les Sciences exactes, et dans les Arts qui en dependent; favoir, l' Arithmetique, &c. That is, An hiftorical Account of the Progrfs of the Human Mind, in the Demonftrative Sciences, and the Arts depending upon them; viz. Arithmetic, Algebra, Geometry, Aftronomy, Dialling, Chronology, Navigation, Optics, Mechanics, Hydraulics, Mufic, Geography, Civil, Military, and Naval Architecture. By Monf. Saverien. Octavo.

Paris, 1766.

W

E are told, in the preface to this useful and entertaining work, that it is the fruit of upwards of twenty years clofe application. In the year 1753, the Author publifhed a wok entitled, Dictionnaire Univerfel de Mathematique et de Phyfique, wherein, under a great number of articles, he gave pretty large hiftorical accounts, and pointed out thofe fources, from which his readers might derive more full and particular information, if they were defirous of it. Since that time, he has himfelf, he tells us, carefully confulted thefe fources, and has collected a fufficient number of facts to form a regular feries of the difcoveries that have been made in the demonftrative fciences. Accordingly, he gives us a clear, and, in general, a diftinct hiftorical view of each fcience, tracing it from its origin, through the feveral fteps of its progrefs, down to the times we live in.

To readers of a philofophical turn, nothing can be more agreeable than fuch a view; it exhibits to the mind a chain of immutable and eternal truths, and conducts it, in a delightful progreffion, from the plaineft and most simple propofitions, to thofe that are the most fublime and complex. It naturally leads our thoughts likewife to the original parent mind, the inexhauftible fountain of light and knowledge, and teaches us to adore that unerring, though unfathomable wifdom, which communicates to mortals fuch degrees of knowledge as are beft adapted to anfwer the great ends of moral government. But let us return ta our Author.