their cruelty juftifies that of Alexander, or that it is my intention to vindicate him in all his actions without exception. He had his faults, because he was a man, and a King. But it appears to me, that Hiftorians in general have been mistaken in his character. They have been too prodigal of their commendations of his courage, and too fparing of their praifes with regard to his other virtues, which tho' lefs brilliant, were more truly eftimable. He had all the qualities neceffary to form the Hero, and many of thofe which conftitute a great King; and only required to have lived long enough, to display on the throne thofe pacific virtues which would have fufficiently attoned for all the blood he had fpilt in his youth."

Having difiniffed the personal character and exploits of Alexander, our Hiftorian proceeds to give an account of the ftate of government, of the army, and of the administration of juftice, under that Prince and his immediate predeceffors. He goes on next, to confider the state of commerce at this period, and of the arts depending thereon:, after which he treats of the customs and manners of common life; of public entertainments; of architecture, fculpture, and painting; of mufic and hiftory; and laftly, of philofophy and religion. We shall quote a paffage or two from this latter part of our Author's performance, to give our Readers an idea of his manner of thinking and writing on these subjects.

"Society, or a familiar correfpondence of people with each other, was at this time abfolutely unknown in Perfia. They lived then, as at this day, in a diftant ftate of gloomy severity, which hath been, in all ages, perhaps, the ftrongest support of tyranny. There was none of that free communication between individuals; none of thofe family connections, which give men a tafte for liberty, by making known the pleasures and advantages of friendship. A number of amiable objects, reserved for the gratification of one man, and a right of employing a number of eunuchs to fecure them for that purpose, were the diftinguifhing privileges of wealth and power. The reft of the nation, who could not afford to purchase fuch coftly delights, were abforbed in idlenefs and ignorance. Thus, true fociety, or those focial pleasures which foften the bitterness of human life, were cultivated only in Greece. Certain indecent feftivals, indeed, are faid to have been kept in Syria. We are told also, of a temple of Venus at Babylon, where modeft women were obliged to proftitute themfelves for hire once a year, and to give to the Prefs of the Goddefs, the reward of their complaifance. But thefe grofs and difgufting customs could not, if true, confuse the happinefs of the people who practifed them. The Greeks alone knew how to furnish themfelves with modet

amu.e

amufements, and pleafures in which they might indulge themfelves without blufhing. Their women were free, efteemed, and refpected; one of the most certain figns of a flourishing state: an equal fign of its wifdom, alfo, was that they had, neverthelefs, little to do with public affairs. Their young men, it is true, gave into the fame exceffes as the youth of all our great cities now generally do. Nothing was lefs common among the Greeks than chastity; that fublime virtue was held in no efteem among them; nor was any body furprized at a man's living with a woman without marrying her, because the practice was general. Even the Philofophers thenfelves did not difdain to adopt this cuftom of the vulgar. Plato, Diogenes, Ariftippus, were the profeffed admirers of feveral Courtezans; and Socrates himself was not afhamed affiduously to pay court to the fair Afpafia. There were not wanting, however, fome who, on the other hand, recommended the virtue of continence. Democritus, in particular, taught, that nothing was fo difgraceful and injurious to ftudy, as to converfe with the fex. Thales alfo taught, that in youth it was too early, and in age too late, to be married. This kind of philofophy, indeed, made but little way. The most beautiful part of the species were interested to put a stop to its progress; and they had more powerful arms than the dry maxims, and vague reafonings, of their adverfaries. Thefe, however, were not the most formidable opponents the fair fex had to encounter: the prepofterous indulgence, at this time, given to the most unnatural paffions, and that by men of abilities and character, who fhould certainly have known better, threw as great an infult on the charms of their fair contemporaries, as it brought eternal infamy on themfelves.

"But, fays our Author, notwithstanding the Grecks acquiefced in fo open a violation of their laws, the wifeft that were ever inftituted, it must be allowed, that the people in general, were much happier than they are at prefent. If there did not fubfift a perfect equality of conditions among them, it appeared, at least, that the meaneft Citizen had an equal right to exiftence with the higheft. There was no fuch thing as deplorable poverty among them; by this I mean, that horrid indigence which deprives a man of the right which nature gives him, to a certain portion of the fruits of the earth, and which fometimes obliges him for want of work, to perifh with hunger, or to relieve his diftreffes by breaking the laws of community. There were but two ranks or conditions of life, thofe of liberty and flavery. If the flaves, however, belonged to a mafter, for whom they laboured, the mafter in return was bound to provide for their fubfiftence. Thofe who were free, were either proprietors of eftates, foldiers, or merchants. There exifted

Nn 4

none

none of that unhappy race of men which we call labourers, who do not even enjoy the advantages of their fervitude. Reduced to the neceffity of cultivating the earth, and gathering its productions for others; cppreffed with the burthen of public taxes, expofed to all the accidental lolles occafioned by the rigour of the fealons; defpifed, infulted, and unconcious of any greater pleafure, than the mere animal enjoys in digefting its food, and propagating is fpecies, I cannot conceive the value of their pretended liberty. But I imagine, that the flavery which we impute to a ftate of barbarifm, is in reality lefs barbarous than that fate of meannefs and fervility in which two thirds of mankind actually languifh at this day.

We learn from the dedication of this performance, to the King of Poland, Duke of Lorrain, that the name of this ingenious young Writer, is Linguet; and are informed by the preface, that he is now engaged in writing the Hiftory of the Age of Auguftus, on the fame plan; in the completion of which undertaking, we with him all that fuccefs to which his rifing merit feems to entitle him.

Introduclic ad Philofophiam Naturalem. Autore Petro Van Mufchenbrock. Or,

An Introduction to Natural Philofophy. 4to. 2 vols. Printed for Luchtmans at Leyden, 1763.

I

Na preface to this work, by Mr. Lulofs the Editor, is given a fketch of its hiftory, from the firft publication of the Author's Epitome Elementorum Phyfico-Mathematicorum, in the year 1726, to that of the prefent performance; his plan having been gradually improving, as may be fcen by his Elementa Phyfice, of 1734 and 1741, and his Inftitutiones, publifhed in 1748 the latter work having been tranflated into moft of the European languages, and univeifally taught in our academies, as a compleat fyftem of phyfics. Our laborious Profeffor, however, fli:l making daily acquifitions in the fcience, and accumulating a number of new experiments, conceived the defign of improving his plan fill farther, in the prefent Introduction; which, it must be allowed, is, in every refpect, greatly fuperior to any of his former publications, and had been probably much more so, had he furvived to put a finishing hand to the work. But this talk was referved for his ingenious Colleague above-mentioned, whole high opinion of the whole, may be learnt by the following paffage.

"Licet fortaflis pofterioribus capitibus quædam adjeciffet Cl. Auctor, ultimam in iiş limam adhibere ipfi licuiflct; omnia

tamen

tamen quæ ad integrum fyftema phyficum pertinent, five utiliffima humano generi et perfpicuis demonftrationibus munita theoremata, five notatu maxime digna recentiorum obfervata et experimenta confideremus, in hac Introductione adco copiore expofuit, ut pauciffima reperiantur fcripta, que hacce opus præftantia æquiparare poffunt, utque, fi illud conferamus accuratius cum anterioribus Cl. Viri fyftematibus eximia ac ingenti labore nata huic incrementa acceniffe facili negotio deprehendamus."

With due deference, however, to our learned Editor, and without meaning to detract in the leaft from the merit of his induftrious and indefatigable Author, we do not think any of the voluminous performances we have foen of this kind, entitled to the appellation of Phyfical Syftems. Phyfics, indeed, hath been fometimes called an experimental fcience, becaufe it is founded on experiments; but there is a material diftinction between experiment and fcience, as there is between the rules of practical mechanics and the theory of natur 1 philofophy. Our celebrated Profeffor hath, like many others, laid down the principles, and illuftrated the theory of mechanics, with fuccefs: but neither are the phyfical principles he hath aflumed, justly founded on experiment; nor do the experiments he hath recorded, ferve to confirm fuch principles. Add to this, that occult qualities are no more admiffible as phyfical, than as mechanical elements; nor do any number of irreconcilable and indigefted experiments, form a theory of any kind whatever. But, to explain ourselves more fully on this head; which is the more neceffary at this time, as our Natural Philofophers, as they are called, follow each other implicitly in the fane beaten track, without feeming to fufpect the fallibility of their predeceffors. Thus our learned Profeffor, in the beginning of his performance, makes no hefitation to adopt the regulæ philofophandi of Sir Ifaac Newton, and thence mistakenly to deduce, what he calls, the univerfal qualities of all bodies. Let us examine, however, how fome of thefe qualities agree with the nature and laws of motion, as laid down by the fame Philofophers.

It is, from an erroneous conclufion, taken for granted, that the elements of a body are folid and impenetrable, and that they Love about in a perfect vacuum. It is alfo fuppofed, that motion may be given to them, when at reft in fich a vacuum; through which they will move quicker, if urged by a greater impulle than if by a lefs, and vice verf. And yet our Author declares, that all motion, however quick, muit take up fome time. "Omnis motus, utcunque celer fuerit, at in tempore, nec ullus motus fieri poteft in initanti." But, if an impenetrable body exilt at reft in a perfect vacuum, what reafon can pomply be given, that it is not moved by a inall impulfe, (if nis.ed

at

at all) as quick as by a great one? Or that, when impelled by either, it would not move through such a vacuum instantaneoufly? The refiftance to fuch impulfe, being null, it would bear the fame proportion to a greater as to a smaller one; fo that, if the impulfe had any effect to make the body change its place, what fhould hinder it from doing fo inftantaneously, and that to any diftance indefinitely? Where there is no refiftance to an impulfe, what fhould occafion the motion, consequent thereon, to take up any certain time? Will it be faid, the vis inertia of the body? What is that vis inertia? Or how can it exift in an impenetrable body, lying at reft in vacuo? That all palpable bodies have a quality, which, with no great impropriety, may be termed a vis inertia, is certain; and also, that the motion of fuch body must neceffarily take up time. But, if a phyfical cause can be affigned for both this quality and phenomenon, it is quite unphilofophical to fuppofe them phyfical principles. And whether this caufe fuggeft itself or not, it is certain that mechanical principles being dependent on physical, fhould never be inconfiftent with them. The truth is, that the laws of motion, affumed by our Author and others, are not arbitrary principles, to be attributed immediately to the Deity, as they fuppofe; but are merely fecondary mechanical principles, flowing, as a neceflary effect, from others ftill more general. Thus the elements of body take up time, in moving from one place to another, and that in proportion to the momentum of the impulfe given them; because they move in a resisting medium; which must be made to give way fucceffively, and cannot overcome a great impulfe in the fame time as a small one. We throw out thefe hints, however, only by way of caution to the young Student, that he may not mistake a system of practical mechanics, for a fyftem of natural philofophy.

With regard to many of our Author's experiments also, we think them too vague and incoherently related, to be of much fervice to phyfical theory; particularly fome of his electrical obfervations, and his remarks De corporibus lucem bibentibus. But, notwithstanding thefe and other fimilar objections, that might be made to this work, confidered as a fyftem, it is undoubtedly the beft and compleateft Introduction to Phyfical Science now extant. The experiments are numerous, and are illuftrated by a great variety of plates, well defigned and engraved; the whole doing honour, in this refpect, as well to the Editor as to the Artifs concerned in the execution of this elegant work.

Extraa