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tical works upon this subject, they may fairly be admitted to contain the moft accesfible store of information which persons ignorant of the science can at present command. They are delivere ed, as much as possible, in the analytical-mode. They take for granted no previous acquaintance with science in the learner ;' and they require, less than any work which we know, the allista ance of apparatus: Dr Black's manner of introducing the newly discovered fübftances; has, indeed, fo great appearance of systematic arrangement; but it should be remembered; that an elementárý treatise has other objects in view, than the attainment of that fair outside which forñs the chief attraction of philosophical systems. After a person, wholly ignorant of science, has fullied chemistry in these volumes, he may have occasion for some sạch work as Lavoisier or Fourcroy, in order to digest and arrange the knowledge he has picked up. But, we believe, every one in, the least conversant with the mater, will admit the impracticability of initiating an ignorant person into the science, merely by the ailistance of those elegant and curioully systematic authors. It is true, we have sometimes felt inclined, in reading this work, to suspect Dr Black of too great contempt for the synthetic form. of instruction. Upon this important point, howeyer, his own arguments, as he delivered ihem in conversation with Dr Hutton and Mr Robison, have been preserved ; and we very willingly transcribe them, às containing a full and plain ftatement of the principles on which the whole course was constructed. Mr Rom bifon had expressed a very favourable opinion of Layoisier's sketch of a scientific arrangement; and had alluded to the happy train of synthetic deduction which it enabled that philosopher to carry through the whole chemical history of bodies

“ This,” said Dr Blačk; « is the very thing I dislike it for. Chemistry is not yet a science. We are very får from the knowledge of first principles. We should avoid every thing that has the pretensions of a full fyAem. The whole of chemical science should, as yet, be analytical, like Newton's Optic3 ; and we should obtain the connc&ing principle, in the form of a general law, at the very end of our induction, as the reward of our labour. You blamed, and, in my opinions juftly, De La Grange's Mechanique Analytique, for being the very opposite to 2 real analytical process for adopting as the fundamental proposition, as a first principle; a theorem which in fact is nothing more than a saga cious observation of an universal fact, discoverable indeed in every mé. chanical phenomenon ; but ftill not a principle, but the mathematical and not the phyfical result of all our inductions. This is not a funda. mental theorem, fit for initruding a novice in the science, but for adepts alone. The case is the same in chemistry. .

" But this is not the greatest fault in the artangement which sets out from the constitution of the atmosphere. In order to get the proofs on which the validity of this first principle mut entirely reft, we mult VOL. 111. 20. 5.

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fall to work with a number of complex, very complex substances, of which we know nothing, and whole modes of action are among the most mysterious things in chemistry; and the conclusions which we must draw; require a steadiness and contention of thought which very few poffels,--which a beginner in philosophical investigation cannot poflibly poffefs. It is by no means fair to appeal to a Lavoisier, a Cavendish, or a Berthollet, or other great chemists, for the clearness of the evidence. They are not the proper judges. Lay it before a sensible metallurgift, ignorant of chemiftry. Ask this man whether he sees the incontroverti. ble force of the proof. When I take the matter in this light, l affirm, that even to a philosopher, the proofs of the fundamental propositions which have been acquiesced in by the authors of this arrangement, are very scanty, very flight and very refined. This is a fault in a syitem published for the instruction of the ignorant ; and, in the present day, it is a very great fault. There is jult now a rage for system,- for complete systems. We have got such a high conceit of our knowledge, that, we cannot be pleaftd with a system which acknowledges any imperfection : It must not leave one open link: It must not leave any thing unexplained. And I see it always happen, that if the application of a fyftem to the explanation of phenomena be very comprehensive, leaving no blanks, and if the explanation have some feafibility, this catches the fäncy; —it dazzles the understanding. Nay, we think it impoflible that a principle that is false can tally with so many phenomena. This feeming coincidence is considered as a proof of its validity ; and 'we are no longer solicitous about the direa proofs adduced in the beginning. I have often heard such arguments for what I knew to be great nonsense. This kind of authority accruing to a theory from its specious and extensive application to phenomena, is always bad ; and, with mere beginners in philosophy, it is doing them an irreparable hurt. It nourishes that itch for theory; and it makes them unsolicitous about the first foundations of it.;--thus it forms in their minds the worst of all philosophical habits.

“ I am resolved to go on in a very different way. I subscribe to al. most all Mr Lavoisier's doctrines ; and I will teach them all. And I affirm that I shall teach them with an impression of their truth which his method can never make. My students shall get all these doctrines piecemeal ;-every one of them by steps which shall be quite easy and confident, because they shall be acquainted with every substance before I employ its phenomena as proofs. Each of Mr Lavoisier's doctrines shall arise in course, as a small and obvious addition to the properties of some fubstance already known. Then I shall carry the student back, and thew. him that the influence of our new discovery, extends also to those subItances which we had been confidering before. Thus, all the doctrines, will be had easily, familiarly, and with confidence in their truth.

"I even think that this method will be more pleasant, the novelties, or reformations, being, by this method, distributed over the whole course. And it will have yet another advantage: It will make the student acquainted with the chemistry of former years, which is far from being unworthy of the attention of a philosopher. Newton, Stalil, Margraaf, Cramer, Scheele, Bergmanp, were geniuses not below the

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common level. But the person who learns chemistry by Lavoisier's fcheme, may remain ignorant of all that was done by former chemists, and unable to read their excellent writings. i

“ I do not find that my old arrangement needs much change: Some I will make chiefly in the order in which I treat the inflammable subitances and the metals. "

We have already mentioned, in general terms, the great additional value which Mr Robison's notes confer upon this publication. Beides a variety of curious and original chemical facts, they illustrate, by several very important documents and acute reafoaings, the history of Dr Black's discoveries. They answer the demand which was long ago made by Mr Nicolson, that some contemporary author should adjust the claims of the several philosophers, who have borne a part in establishing the doctrine of latent heat. * They prove to a demonstration, that the undivided honour of this grand discovery is due to the author of these Lectures, whose amiable and dignified modesty prevented him from taking the necessary steps to secure his own claims. The following states. ment of the attempts that have been made to rob him of his just fame, prefents no very pleasing picture of the philosophical cha. racter, and we are almost inclined to hope, that Mr Robison, from whom our authority is derived, has been mistaken in his decifions. We feel it our duty, however, to give the circumstances to the public as he has detailed them ; premising that we are sorry we can see no immediate reasons for doubting his accuracy, while we rely most implicitly on his veracity and candour. :)

Dr Black never published his own account of the discovery, buo he gave it every year after 1760, in his Lectures, to very numerous classes of students from various parts of Europe. It is proved, from his note-books, as well as from the concurring teftimony of Messrs Robison and Watt, that he completed this discovery, as far as regards aqueous fluidity, between the years. 1:754 and 1757. We have already remarked, that he immediately extended it to the case of aëriform fluidity, even before he had actually performed the experiments by which the application is illustrated in detail. Among his pupils, Dr Black had many gentlemen of Geneva particularly a M. Chaillet, in 1763, and a Dr. Odier, who COIL responded with M. De Luc, and communicated to our country's man several of that gentleman's meteorological observations. A Swedish gentleman, of the name of Willems, or Willemion, (from Stockholm), was also much in the company of Dr Black and his friends, about the year'1768. He was wholly occupied with chemical studies. From none of these itudents was the fightest hint ever obtained, that a doctrine in any degree retem. bling, that of latent heat, had been known in Geneva or Sweden.

. ...... B 2 ... . .. While 'Tranlation of Fourcroy, 27. fe&t. of the valuable Note to Pt. I. ch 5. $ 2.

· While the communication between this country and those parts. was thus constant, manuscript copies of Dr Black's lectures were in very general circulation among his students. They were even sold at a moderate price; and they contained accounts of his discoveries, if not altogether correct, at least abundantly copious for all the purposes of plagiarism. In 1770, a furreptitious publication of them was made by a London bookseller, under a general title; and this work gave a very distinct ftatement of the leading parts of the doctrine, with a full acknowledgement that Dr Black was the discoverer. in 1772, Mr Wilcke of Stockholm read a paper to the Royal Society of that city, in which the abforption of heat, by melting ice, is described; and in the same year, M. De Luc of Geneva, published his Recherches four les modifications de l'Atmosphere, in which the doctrine is, with much less accuracy, employed to explain fome meteorological facts.

Our readers will probably have anticipated the conclusion which this statement of circumstances forces us to draw,-that both the one and the other of these gentlemen, in all probability, owed their knowledge of the absorption of heat to the diffusion of Dr Black's discovery, through the medium of his Ledures. But the subsequent conduct of M. De Luc deserves our farther attention ; and leaves as little doubt, with respect to his culpability, "as can exist upon a question of this fort. · About the year 1782, Dr Black was informed, that M. De Luc carnestly wished to become the editor of his observations up. on latent heat, in order to secure Dr Black's claims to the dire covery, from the attempts which were continually made by 0thers to appropriate it. In consequence of repeated solicitations, Dr Black gave his friend Mr Watt permission to communicate the leading points of his theory, and instructions to perform the ex. periments before M. De Luc. Neither the Doctor nor his friends had now the smalleft anxiety upon the fubject : they trusted in the promise of the Genevese philosopher, and expected to see in his great work, a full vindication of the claims which he had anxi. qusly volunteered to defend. The publication at last arrived ; and the mode of defence was somewhat novel. It conlisted in a refutation of the claims urged by others, and an assertion, that the discovery of latent heat was entirely M. De Luc's own, Dr Black being only allowed the merit of having first attempted to measure the exact quantity of absorption in the particular case of aqueous fluidity. Mr Watt then wrote a letter to M. De Luc, containing a full explanation of Dr Black's discovery, and insisted that this should be published in the next volume of the work. It appeared accordingly; but was accompanied only by an acknowledgement of the fatisfaction which M. De Luc received, from Learning that his own fyftem had so able a defender as Dr Black;

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2 circumstance, he adds, which will give him new confidence in the doctrine.

From the foregoing statement, then, it appears, that M. De Luc published a work, containing a few crude ideas on the combination of heat; that he afterwards became better acquainte ed with the subject ; that he formed a design to pass for the au. thor of the doctrine, by completing his knowledge of the theory, and twisting his former vague Statements into some kind of s. milarity ; that, for this purpose, he applied to the man whom he knew to be the discoverer, and obtained, from him, a full account of the matter, under the pretext of defending his claim a. ' gainst others; that, instead of fulfilling his promise, he only refute ed the claims of those others, in order to bring forward his own; converted the documents which he had procured, to his own use; and concluded by politely laughing at the person whom he had thus defrauded. Such is the amount of the impreffion made by Mr Robison's narrative, in the eighth note to the first volume. We wish that some friend of the Genevese philosopher could ftep forward to clear him from fo fout a charge. We are wille ing to hope, that his conduct may be explained in a way confift. ent, at least, with the belief of his honesty; for who can hesie tate to pronounce, that the conduct here imputed to him, would have been deemed common impofture, if avarice, not vanity, had been the motive, and money, not fame, the end ?

Mr Robison has incorporated with the text of these Lectures, vol. II. p. 215, some very curious observations upon the conduct of Lavoisier and his associates, both towards Dr Black, and in the establishment of their new chemical system. We rejoice that this subject is fairly brought before the public; and, on whichtver Gde the decision may finally be given, the history of the science, as well as the political history of the times, is likely to be illustrated by the discussion. That the Frence chemists formed themselves into a junto for the propagation of their syfe tem; that, like all juntos, they delivered their doctrines with an authoritative tone, highly indecorous in matters of science ; and that they even displayed somewhat of a spirit of persecution towards those who, from ancient habits, or from a predilection for their own new theories, refused their affens to the antiphlogistic doctrines, are facts which cannot be disa puted. As little can it be denied, that the Parisian philosophers, animated, like all similar associations, by an esprit de corps, and mingling with this, very strong national partialities, arrogated to themselves the merit of every important discovery, nay, of almost all the detached observations, which had been made in any part of Europe, during the latter half of the eighteenth century. Now, Ms Robison requires us to go a step farthes, and to admit

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