algebraical calculations. The prosecution of this plan produced a volume of tracts, in 1761, which contained many curious inveftigations, especially concerning centripetal forces, and a method of determining the fun's diftance, from his effect in difturbing the moon's motions: a fupplement to this laft tract was afterward published by itself, and about the fame time his work, intitled Propofitiones Geometrica more Veterum demonftrata, made its appearance.

Dr. Stewart fucceeded Mr. Maclaurin in 1746, as Profeffor of Mathematics at Edinburgh, which office he discharged till 1772, when his health obliged him to retire from the duties of his profefforship, which he committed to the care of his fon, Mr. Dugald Stewart, who was elected joint profeffor with his father in 1775.

After mathematical ftudies had ceafed to be the Doctor's bufinefs, they continued to be his amufement: the analogy between the circle and the hyperbola had been long the object of his contemplation, and his biographer, Mr. Playfair, the prefent profeffor, informs us, that he has left fome valuable obfervations on this curious and important fubject, especially an approximation of the circular and hyperbolic areas. He died January 23d, 1785, at the age of fixty-eight.

As the habits of study, in a man of original genius, are objects of curiofity, we shall transcribe the following character of this great geometrician :

His writings have made it unneceffary to remark, that from his youth he had been accustomed to the most intenfe and continued application; in confequence of this application, added to the natural vigour of his mind, he retained the memory of his discoveries in a manner that will hardly be believed; he rarely wrote down any of his investigations, till it became neceffary to do fo for the purpose of publication. When he discovered any propofition, he would put down the enunciation with great accuracy, and, on the fame piece of paper, would conftruct, very neatly, the figure to which it referred to thefe he trufted for recalling to his mind, at any future period, the demonftration, or the analyfis, however complicated it might be. Experience had taught him that he might place this confidence in himself without any danger of disappointment, and for this fingular power he was probably more indebted to the activity of his invention, than the mere tenaciousness of his memory. Though he was extremely studious, he read few books, and verified the observation of M. D'Alembert, that, of all the men of letters, mathematicians read leaft of the writings of one another his own investigations occupied him fufficiently, and indeed

*For the contents of this volume, we refer our readers to the Monthly Review, vol. xxv. p. 458; and for the fubfequent controversy which they occafioned, vol. xxx, p. 53, and vol. xlv. p. 233.

the

the world would have reafon to regret the mifapplication of his talents, had he employed, in the mere acquifition of knowledge, that time which he could dedicate to works of invention.'

Next in order, after the lives of deceafed members, follow the lift of donations, the lift of the members (among which we recognise fome of the most refpectable names in Europe), and the lift of the prefent officers.

The Memoirs will be the fubje&t of a future article.

ART. IX. Principles of Surgery, for the Ufe of Chirurgical Students. Part I. By John Pearfon, Surgeon to the Lock Hofpital, and to the Public Difpenfary. 8vo. 5s. Boards. Johnfon. 1787.

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N the discharge of our duty, in the chirurgical department, we have frequently lamented, that the fcientific part of furgery is not at prefent fo much attended to by the ftudent, as the practical, or merely operative. A fhort attendance on the hofpitals, and a frequent appearance at the lectures, form, in general, the chief of the furgical Tyro's ftudies: the knowlege of phyfiology, equally important to the furgeon as to the physician, is almolt wholly neglected, and the niceties of anatomy are accounted, as the fafhion now is, of greater confequence than a perfect acquaintance with the diagnoltics and prognostics of difeafes. Let not our Readers imagine, however, that we would difcourage the ftudy of anatomy. It is a ufeful branch of knowlege, and it is the bafis of furgery; but, when a young man employs the whole of his time in pursuing the minute ramifications of the extreme and invifible nerves and blood veffels, which are merely matters of curiofity, and can never be of the least use in the exercise of the furgical art; he lofes the opportunity of improving himself in the nature of diseases; and if he become a good and neat operator, without having judgment to direct him in what difeafes, or in what period of a difeafe, the operation ought to be performed, he will be little better than an automaton, and will conftantly require the advice of the fcientific furgeon. This erroneous mode of purfuing the ftudy of an art, which is the most useful to mankind, proceeds too frequently from the profeffors, and not from the ftudents. If profeffors direct not the pupil in the right road, how can it be fuppofed that he fhould purfue his ftudies with advantage? The fact is, that profeffors, in general, dwell more on explaining their own discoveries, or unfolding their own hypothefes, than inculcating the principles of the fcience; thus the pupil is habituated to think that a knowlege of what is new, and an acquaintance with a peculiar fyftem, are the effential qualifications of a practical furgeon; and if, in addition to thefe fuppofed requifites, he can ufe a knife handfomely, as the phrafe is, he begins his chirurgical career with confidence, his progrefs is marked with blood, and

I

mutilated

mutilated patients record the wonders that his hands have wrought. The truly fcientific furgeon, on the other hand, knowing the ftructure of the human body, and having duly obferved the ways of nature, proceeds with cautious steps, and a judicious practice gains him deferved applaufe.

Mr. Pearfon, by the work before us, appears to be of nearly the fame opinion with ourfelves; he fhews, in an elaborate preface, the great neceffity of reforming the prefent mode of furgical education, and establishing the practice on scientific principles, and a proper knowledge of difeafes.

He first treats of inflammation in general, explaining its phenomena, and inveftigating its remote caufes. He is cautious with refpect to what he advances on proximate caufes, well knowing the difficulty of the fubject, and the diverfity of opinions which have been advanced on it, by moft of the learned and ingenious medical men in all ages. To expofe the fallacies of preceding fyftematic writers is no part of his prefent bufinefs, and he endeavours to avoid the cenfure of temerity, by faying that he is unable to affign, in a fatisfactory manner, the proximate caufe of inflammation. He then proceeds to fhew the difference between general inflammation and erethifmus, and defcribes the progrefs of inflammation, with its termination in refolution and fuppuration. In the direction for the treatment of inflammation, Mr. Pearfon difplays much practical knowlege and great judgment.

In the fecond chapter, the author treats of the furunculus or boil; in the third, of abfcefs in the breaft; in the fourth, of paronychia and panaris; in the fifth, of empyema pfoadicum; in the fixth, of gangrene and fphacelus.

We wondered that Mr. Pearfon had not enumerated gangrene. and fphacelus among the terminations of inflammation; gangrene certainly follows, and is a confequence of, inflammation; and though it may fometimes appear without any previous inflammatory fymptoms, yet order required that it fhould have been mentioned under inflammation.

The fubjects of the fubfequent chapters are, anthrax, pernio, burns, eryfipelas, fchirrhus and cancer, ozaena and canker.

Such are the contents of Mr. Pearfon's work, which, we are informed, was primarily defigned as a text-book for the ufe of the gentlemen that honour the author with their attendance on his furgical lectures.' Mr. P.'s arrangement is, we think, fometimes objectionable, and his ftyle is frequently dogmatical, but he prudently forewarns the reader of thefe defects, by faying, ⚫ that many parts of the work are little more than a sketch of what is delivered in the lectures, nor is the order in which the different morbid affections are treated, to be confidered as an attempt at a fcientifical arrangement." REV. June, 1788.

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On the whole, Mr. Pearfon has beftowed great pains on the performance, and we hope he will proceed with his work, and at the fame time make fuch additions to this first part as he may judge neceffary. As a text-book, it is rather too minute and particular; as an elementary book, not, fufficiently explicit and satisfactory to the reader.

ART. X. An Effay on the Powers and Mechanifm of Nature; intended, by a deeper Analysis of Phyfical Principles, to extend, improve, and more firmly establish, the grand Superftructure of the Newtonian Syftem. By Robert Young. 8vo. 6s. Boards. Becket, &c. 1788.

BY

Y the Newtonian fyftem, Mr. Young means, the fyftem of the world, difcovered by Pythagoras, revived by Copernicus, and, by the aid of a fublime and exquifite geometry, brought to its prefent ftate of perfection by Sir Ifaac Newton;' and, after ftating that this fyftem is imperfect, in the preface, he fays:

The following Effay is intended to improve the phyfical principles of philofophy, in order to extend our knowledge of nature. If I have fucceeded in thefe views, it will be no objection to my attempt, that I have deviated from principles already eftablished, fince it is obvious, that every advance in knowledge implies the difcovery and renunciation of fome error; he who will adhere immutably to tenets once adopted, can never increase his light, nor improve his understanding.'

He then infifts on the neceffity of liberty in reafoning, inveighs against thofe who, in fcientific matters, put implicit faith in human authority, and proceeds as follows:

Many will object to the method of reasoning herein followed, that philofophy has only to collect general laws from phenomena, and then apply thofe laws to the explanation of other phenomena; and has no concern with metaphyfics. To this I answer, that the prefent is a phyfical, and not a metaphyfical work (if metaphyfics are to be loaded with an unmerited opprobrium); that the object of my inquiry is not facts but powers, not effects but caufes; that the received theory doth not, agreeably to its profeffions, confine itself to the affertion of phenomena, but affumes, as caufes, phyfical principles, which are not matters of fact, nor laws collected by induction, but which are to be examined by phyfical reasoning alone. principles, thus affumed in the received theory, I have not adopted, and therefore it became neceffary to fubftitute others in their place, and to this end I have employed the following pages. I have not attempted it by means of experiments, because they can difcover effects only, and not caufes which I fought; nor by geometry, because it is concerned only with relations of quantity, and cannot lead to the knowledge of being or of power.

Thefe

By phyfical reafoning alone I have found a phyfical principle adequate to the purposes of explaining phenomena; a substance ac

tually

tually exifting, poffeffed of active powers, the bafis of matter itself, and the agent in all effects. This active fubftance appears to have been the defideratum in all ages of philofophy; it removes the obfcurity which attends the confideration of matter as an original and inactive fubftance, whofe effence, folidity, is confeffed to be incomprehenfible; it removes the difficulty which has ever attended the queftion of the origin of motion, by fhewing motion to be the original form of being; and thus reflects a light upon the very foundations of fcience.' From these extracts, our readers may perceive what is Mr. Young's intention in the prefent work, and alfo the methods which he has used in executing it. We fhall now briefly ftate the contents of the effay before us.

In the introduction, Mr. Young remarks, that philofophical principles are of two kinds, experimental and rational; the former are general facts, which are found uniformly to obtain; the latter are conceptions of the understanding, whofe evidence refts not alone on experiment, but on intuitive perceptions.' To arrive at thefe, he fays, we must exercise our intellectual faculties.' He afferts alfo, that firft principles, not being objects of fenfe, are therefore not to be fought by experiment, but by reafon and intellect, and by analyzing thofe things wherein they exist.'

The first part of the prefent performance has the general title, Analysis of Matter and Motion;' in which our author confiders the qualities of bodies, and thence proceeds with his analyfis. The principal conclufions which he makes are, that folidity rofolves itself into power or activity;' that inactivity is a privation, and incapable of analyfis;' that matter is both active and inactive in different refpects; its component parts are active, and, by their action, conftitute matter as an whole inactive;' that inactivity has no relation to motion, but is its negation; that the effence of body is power;' that cohefion is a power which, either in holding together any number of primary folid parts, or in conftituting one primary folid by holding its own parts together, is fimilar both in its nature and mode of operation;' that matter is not impenetrable.' In the chapter allotted to the Analysis of Motion, Mr. Young fays, 'We cannot conceive of any actual motion, without combining together these three ideas, a being which moves, a place in which that being is, and the change of that place.' After defining and explaining being, place, change, he concludes that all motion implies action, and depends on an active caufe.' He then confiders motion in its parts: every motion,' he says, 'has a beginning, a middle, and an end;' each of these he treats feparately, and, after some reflections on Sir Ifaac Newton's definitions, he fhews that all motion is produced and continued by action. Action,' Mr. Young fays, depends upon, and implies, the presence of a fubftance which is active;' and he concludes, that there is

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therefore