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which were of importance, from his own recolledioa of incidents, casusly iet don?.

. There are some in shich he seems to have inserted every thing as it frok tis fares, in recipe, ceairy, jurii prudence, or matters of 12**e; and 1 and others irio stich le bas irzesierted the same things, tut tas de tributed tien acco: d 32 ta their sciectibe connexions. la fort, he has kept a journal and lezer of his sucies, and has poed his bocka Ike a .erchant. I have lov'sed over the memorandums wib fome care, and have there seen the first germs of those discoveries which have at kit produced such a complete revolution in chemical science. What paricu ariy ftruck me, was the fileadiness with which be adranedin 299 pa:b of knowisdie l a retratfun. Things are inserted for the first time, from some present impreffion of their fingularity or impostauce, but witbout any adufion to their connexions. When a thing of ibe lame kind is mentioned again, there is generally a reference back to its filow; and thus the most insulated fa&s often acquired a con. nexion shich gave them scientific importacce.' Preiace, p. xxi. xxii.

Mr Robiion has performed the doty entrusted to him by his friend's execu:ors, in such a manner as muit entitle him not merely to their thanks, bur to the lafting gratitude of the scientific world. He has pretented us with a very tail, and apparently a very accu. Iste collection, of the most valuable parts of the lectures, as nearly as postible in the very words of the teacher. He has faithfully adhered to the arrangement of the course, except in two instances, where a fught charge seems to be perfedly justified by the convenience which attends it. His preface contains a clear and compendious account of the import of Dr Black's discoveries, and a very interesting sketch of his life. In the fooi-notes, he has ocea. fionally added to the rich collection of facts and observations contained in the text, leveral valuable remarks and statements fuggested by his own experience. Iu the more copious notes subjcined to each volume, he has introduced various difcuffions of the highest importance both to the elucidation of the general subject, and the establishment of leading points in the history of the science. Let our scientific readers consider, how much of all this confifts in mere labour, unrepaid by the peculiar reward of genius; and let them remember that Mr Robison's talents are as original as his acquirements are various and profound : they will then be able to estimate the extent of the obligations under which he has laid them by editing this valuable work.

It would be perfectly inconsistent with our plan, and far ex. ceed our limits, to analyze these lectures, or the commentaries of the editor, which, like the text, must necessarily be very miscellaneous. We shall confine ourselves to a few general observations on each of the two departments; and fall, in the firft place, endeavour to make our readers acquainted with the illus

trious man whose life and discoveries confer upon the present pub. lication its chief interest.

Joseph Black was fprung from a Scotish family, transplanted firit to Ireland, and then to France, the country which gave him birth. He sperit, in Bordeaux and its vicinity, those years of infancy devoted by the constitution of human nature to imbecility, thrallom and ignorance, and extolled, by the general consent of mankind, as the leason of genuine happiness. The biographer has wisely passed over the history of this blissful period, and preferred dwelling upon those scenes which display the ripened powers of the mind. After an account of the intimacy which subsisted between the amiable parents of the philosopher and the celebrated president Montesquieu, the narrative is pursued from the periodo of Dr Black's removal to Belfast, in the twelfth year of his age. He there received the rudiments of his literary education, and finished it at the University of Glasgow, the scene of his future discoveries. His attention appears to have been divided between the science which his natural bias led him peculiarly to cultivate, and those more general objects of speculation which enlarge the understanding, while they improve the taste. Although his application to these delightful pursuits was never very ardent, it was steady and vigorous. If he did not, like Pascal, Newton, MʻLaurin, and various writers on lighter subjects, astonish the world by a premature display of talents, his want of those stronger patsions, which lead to an early developement of genius, infured him the pofleflion of a calm and immoveable judgement, a patient capacity of observation, and a modest distrust of theory,

che moit effential characteristics of the inductive philosopher.

In the course of his studies, he does not appear to have entered deeply into the abstract sciences, either of mathematical or metaphysical truth. His taste led him rather to the contemplation of real and external objects, and he soon employed as much of his talents as he ever devoted to severe study, in the investia gations of experimental philosophy. The physical discoveries of Sir Isaac Newton attracted his chief admiration; and, upon the unequalled models of inductive disquisition which the treatise of Light contains, his scientific habits were happily formed. After he had, by his own discoveries, laid the foundation of a revolution in science, almost equal to the changes which his great mafter had effected, we find him l-adily perfevering in the same Itrict and chartered fyftem of inductive logic, and freely acknowtedging the fources of his skill. - My acqnentance with him (11;3 Mr Robifon) began at Glasgow in, 1758, I being then a sludent in that Univerfity; and it began in a way auch marked the diftinguiled aniableness of his disposition and bea

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haviour. It was at the house of one of the professors, to whom I was telling the great entertainment I had received from the lectures of Dr Robert Dick, Professor of Natural Philosophy, and how much I admired him as a lecturer. Dr Black joined in the commendation ; and then, addressing himself to me, questioned me a good deal about natural philofophy, so as to perceive what were the peculiar objects of my attention. His advices relative to my favourite study were so impressive, and given in a manner so unaffectedly serious and kind, that they are still as fresh in my mind as if of yesterday's date. I was a stranger to him, and not even his pupil; and he was prompted to take that pains with me, folely by the way in which he heard me speaking of the lectures of one whom he loved and esteemed. Gently and gracefully checking my disposition to form theories, he warned me to fufpect all theories whatever, presled on me the necessity of improving in mathematical knowledge, and gave me Newton's Optics to read, advising me to make that book the model of all my studies, and to reject, even without examination, every hypothetical explanation, as a mere waste of time and ingenuity.' Preface, p. vii.

The profeffion of medicine, which Dr Black chose from its consonance with the tenour of his favourite studies, was extreme. ly unsuitable to his delicate constitution, and the amiably solicitous temper of his mind. The duties of his station as a physicran, and of fiis' three fucceslive profefiorfhips, were, unfortunately for science, (we may add, for his own fame), matters of such anxious care, as to distract much of his attention from the path of original investigation, which he had entered with the moft fplendid prospects of success. The doctrine of latent heat appears to have been early familiar to his thoughts. In the oldest parcels of his notes, Mr Robison found queries relative to this point; and Dr Black himself asserts, (vol. I. p. 156.), that he can scarcely remember the time when he had not some idea of the disagreement of the facts with the common doctrines of heat. The extracts from the memorandum-books given in these volumes, sufficiently prove, that, while a student, his ideas had been somewhat matured upon the fubject. Before the year 1763, his whole experiments and inquiries on the absorption of heat, were brought to a conclusion; and his inaugural differtation, when he received a degree in 1754, contained an account of his other grand discovery—the nature of the alkaline earths, and the properties of fixed air. He removed from Glasgow to Edinburgh in 1766, and died in 1799. How great a part, then, of this most valuable life was spent in the mere exercise of professional duties! At an age when the bulk of philosophers are only beginning to strike out new lights, Black had closed his short career of brilliant discovery; entered upon the common task of a chemical teacher; limited his ambition to the simple explication of a science which


he might have created anew; and left to his more ardent, or more fortunate succeflors, the glories of rearing a system, of which he had laid the firm foundations, and furnished the chief materials. We shall afterwards see, that they are charged with re. fusing to engrave his name upon the structure, and to bestow his portion of honour on him whose genius and ill fate had left them so ample a share.

In contemplating the intellectual character of this eminent per-, fon, we cannot fail to be delighted with the observation of that unity which seems peculiar to minds of the first order. An original genius is often to be found in all the departments of human excellence. But it is rarely, indeed, that we can discover one whose features are at once distinctly marked, and nicely blended ; each different from the ordinary cast, and all animated by the same spirit. The most astonishing intellect that has ever been permited to enlighten mankind, poffessed this rare harmony in the very highest degree. Those qualities which distinguished the father of inductive science from every other philosopher, were equally conspicuous in each of his various exertions; and the preeminent dignity of his powers was sustained through all the thousand operations by which he enlarged the grasp of the human mind. It is in vain that we search every corner of the Newtonian writings, for some trilling proof that their author was, like ourselves, liable to the common intellectual failings of the species. We ace consoled by no glimpse of wavering steps, even on the most delicate ground; or hafty advances, where the footing is fureft, and the prize most attractive ; or careless examination, where the intermediate objects are most trivial ; or relaxation, when the greatest obstacles have been surmounted; or intemperate triumph, when the most dazzling prospects are displayed. Each height is reached by the safest and the shortest path, with the smallest bustle ; and the attainment is only valued as leading to some loftier emi. nence. Each position is alike marked by its distance from the ordinary level; by the nature of the works which secure it, and of the country which it commands. The chief characteristic of Newton, is the degree of superiority in which he towers above every other natural philosopher, so as to form a class by himself. But the kind of his excellence is also remarkable and uniform. The distance and dissimilarity of the objects which his discoveries enable us to compare, is not more astonishing, than the cafe and simplicity of the means of comparison. The pleasure of contemplation, which forms the primara object of all abstract science, and which the view of those comparisons invariably bestows, is equalled by the practical importance of the consequences to which they may be applied. The enunciation of the proposition is not A 3


more unexpected, than the demonstration is flowing, and the corollaries useful. All thofe various investigations, too, are the easy and natural work of one great, fimple mind, versatile in the direction of its efforts, but uniform in its mode of operation ; not the attempts of an ordinary intellect, ftraining at universality by ambitious mimicry of different talents.

In these particulars, we cannot avoid observing a striking analogy between the philosophical genius of Black and that of Newton. None of this illustrious man's followers has fo correctly seized the true spirit of inductive reasoning by wbich he was guided, or combined so happily the utmost finplicity of means with the accomplishment of the most difficult and important ends. In all Dr Black's analytical inquiries, we perceive how much be. longs to the mind of the observer; how little is left to the trick and dexterity of the operator. By placing nature in new combinations of circumstances, he extorts from her (to use the language of Lord Bacon) some of her sublimeft fecrets : But there combinations are always simple and conclusive. He knows, too, that the ordinary combinations which we witness every hour, require only patient observation, to furnish the unbiated seasoner with ample opportunities of generalization. Accordingly, in no. fcientific inquiries, since the date of the Principia and Optics, do we find so great a proportion of pure ratiocination, founded upon the defcription of common facts, þut leading to the most unex. pečted and important results, as in the two grand fyftems of Black. This mode of investigating the laws of vature has various advantages of the highest consequence. It diminishes incalculably the chances of mistake, by precluding the use of complicated apparatus. It brings home to every one the evidence of the discoveries, and exposes the demonstration of each proposition to the most fevore and universal scrutiny. It opens, to all who can ob. firve and reason, the field of important inquiry, and raises the mind to the most general views of the constitution of the world.

The fame happy turn of mind which placed the scientific inveligations of Dr Black so near the greatest discoveries that have eyer been made by the species, was perceptible, also in the clegance and ingenuity which it mingled with all his personal habits,

. I have already observed,' says Mr Robison • that when I was first acquainted with Dr Black, his aspect was comely and interestig. As he advanced in years, his, countenance continued to preserve that pleaf. ing expression of inward fatisfa&tion, which, by giving case to the beholder, never fails to please. His manner was perfectly easy, and unwiņi ded, and graceful. He was of most easy approach, affable, and 11 ddily entered into conversation, whether forious or trivial. His mind

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