ART. III.-Supplement to the Third Edition of the Encyclopedia Britannica, &c. By George Gleig, LL.D. &c. (Continued from p. 170.)

WE return with great satisfaction to this valuable appendage. The first article particularly interesting in the second volume is that on induction: it is short, but comprehensive, and truly important. The author suspects, and with reason, that nothing can be proved by categorical syllogisms, since they assume, in the major, a generic distinction, applied to the species; in other words, they assume in general what they mean to prove in particular. Mathematical investigations, which have been considered by many authors as a concatenation of syllogisms, are shown to be a very different process; but we may still doubt whether any thing, strictly speaking, be discoverable by mathematical reasoning, since the investigation is only an evolution of what is contained in the problem or theorem. So far as that evolution brings to view what was formerly concealed, it may be styled a discovery; but discoveries, in reality, are only the connexions of unexpected relations, ascertained and improved by experiment and scientific investigation. The author seems however at a loss, when he compares the truths of geometry with those of physics; and endeavours to explain, somewhat unsuccessfully, why the former are necessarily true, and the latter contingent. In reality, as we have had occasion to remark, the error is in adopting the same term of axioms in both sciences. They are not on the same footing. The mathematical axiom is indeed invariably and necessarily true; but the philosophical axiom is a fact only, of which the contrary has not been proved. Thus also in the conclusions: the mathematical demonstration cannot be controverted, because it depends on given quantities and precisely defined properties: in the philosophical conclusion we can seldom obtain either.-But we must not be diffuse.

The facts relative to ( spontaneous inflammation' are collected with great care and accuracy. Many of them are curious. Under the article institute' the author collects the account of the constitution of the French National Institute, and properly reprehends the absurdity of many of the innovations of that futile nation.

This statement of facts relative to the present state of public instruction, the sciences, the arts, and the progress of national literature in France, has been taken from a miscellany, of which the principal writers are well acquainted with what is doing in that distracted country. They call it a sublime system; and seem to consider the increase of the national library, the improvement of the

botanic gardens, and the discoveries that have been made by the different schools or institutes, as furnishing a demonstration that the republican government is more favourable to the advancement of science, than the monarchical, whether absolute or limited. But it should not be forgotten, that this system is yet in its infancy; and that in prosecuting new schemes, all men, and more especially Frenchmen, are actuated by an enthusiasm which gradually cools as their pursuits become familiar. We shall therefore venture to predict, that the different schools will not display such ardour seven years hence as they do at present; and that if the republican government continue a dozen of years in France, the progress of science in that country will not be more rapid than it was under the monarchy. We must remember, too, that the French libraries, museums, and picture galleries, have been improved by means which the morals of other governments do not employ-by rapine and robbery.' Vol. ii. P. 12.

Had the author examined the transactions of this establish ment as we have done, his suspicions of the failing ardour of the new members would have been confirmed.--Under the article of life insurance,' we suspect the flourishing state of some of the societies would now admit of a different representation; at least it appears so, from the lower rate of interest given. In fact, we have strong reason to believe that the value of human life is much greater than any tables have represented.

The article of involution and evolution' is an admirable one. Indeed the reference to the first and original authors, as well as the firmness with which he supports the character of our chief mathematicians, and of the higher geometry, confer the utmost credit on the gentleman who conducts this part of the Encyclopædia. The article iron' is again introduced, to notice the observations of M. Chaptal on the use of its oxydes in dying cotton.

We find, in this second volume, the same attention to late voyagers, and their descriptions of the countries visited; though probably too much deference is now paid to Vaillant. Since our possession of the Cape, we have had great reason to believe many of his descriptions to be little better founded than those of Damberger. The article lamp' is a valuable one, and contains the substance of all the memoirs, and other works, published with a design of increasing the light, lessening the expense, or rendering the instrument more commodious. The article of 'lava' is again inserted, to notice sir James Hall's experiments, by which he endeavours to show that whinstone is lava cooled slowly, without the access of air. The article of machinery' comprehends, in a very perspicuous manner, the considerations of the different estimates of the power exerted, and explains with wonderful simplicity the theory of machinery. In all working machines, the power and the resistance equipoise each other, like a steelyard, "loaded by its balanced

weights, and moved round its axis by a force distinct from either, This force is the excess of the impulse beyond what balances the weight before the machine has acquired a uniform motion; and in this way the calculations are rendered peculiarly easy and clear. Some observations on the improvement of machines are subjoined. Bramah's new power, founded on the hydrostatic paradox, is explained in this part of the article at some length. It is afterwards again alluded to, and is a most interesting and useful application of a well-known truth.

The article of magnetism' is full and comprehensive. We hoped to have been able to give an abstract of it within a moderate compass; but the substance is so closely compacted that we soon relinquished the attempt. It appears to us to contain the quintessence of all that has been written on the subject; except, perhaps, that the difference between magnetism and electricity is not sufficiently pointed out; and Van Swinden's collection of memoirs on the analogy and discrepancy of these fluids, (crowned with applause by the Bavarian academy) which contains some very important facts, has not been apparently. seen by the author.

An article on man' is again inserted, in opposition to infidel ignorance,' which still, it is said, contends that the various races could not be the offspring of one pair. We are not aware that the opinion which the author opposes is allied to either infidelity or ignorance. We own that we have, at times, spoken in favour of it; and yet we know that few merit less the appellation of infidels, and few have, at least, taken more pains to examine the different facts. We think it not inconsistent with divine revelation, unless what is apparently intended as particular history be considered, against all internal evidence, as universal; and men whose religious characters have been unimpeached, and unimpeachable, have thought the same. The additional evidence in this new article is not very im-, portant: it arises chiefly from the analogy of swine. Undoubtedly, among the human-race, there are many Epicuri de grege porci; but we trust all are not so; and the arguments in support of the analogy between mankind and their new allies appear to us, at least, inconclusive. In the article of manure' we find a very judicious abstract of M. Parmentier's memoir on that important subject. This memoir, it is added, is the result apparently of theory and practice, and much information may be derived from it; but the subject is still obscure. M. Parmentier's chief merit consists in the remarks on the union of different soils; and thus we find deep ploughing, which sometimes contributes to this union, not only successful, from mixing the sub-stratum with the soil above, but from exposing the whole to light.

In the article masonry, we again find a recurrence to what we

think some part of the author's weak side. The essence and secret of masonry is said to be liberty and equality;' and therefore masons were the innovators of the modern school. But we have enlarged sufficiently on this subject.-The new article of mechanics' contains some just remarks on machines in general; on motions and moving powers; distinguishing chemical from mechanical motions.

The subject of mineralogy' we have followed with unceasing attention, and are well pleased to see so accurate and comprehensive a view of the subject. In an age of accumulating discoveries, particularly when considerable attention is paid to one topic, there is no period in which the view will be complete. In the moment of writing and of printing, additions will be made; and though this volume were printed only in the last year, various improvements have since occurred; and in the volumes of Hauy and Brochant much additional information may be obtained. The diligent inquiries of the author, however, have rendered it considerably more perfect than could be expected; and much of what has been published by Hauy in his work, we perceive, is here taken from the Journal des Mines, where it first appeared. The index is not The index is not perhaps sufficiently full; and of Werner's language the author's idea is not always correct. The only original part is the artificial system, suggested in the article before us. As it is highly ingenious, we shall add a short abstract of it. An artificial system of mineralogy is an arrangement, reposing on obvious properties, independently of all chemical nature. The classes are derived from the degree of fusibility, and are six in number; viz. infusible, fusible, fusible by the blue flame only of the blowpipe, fusible and partly evaporating, evaporating, and soluble with effervescence in the muriatic acid. The orders are chiefly taken from the respective specific gravities, sometimes with slight additional characters; and the genera from colour or other obvious properties. It is, as we have said, a very ingenious attempt, and merits particular commendation.

On the subject of moss the author gives an abstract of Mr. Smith's method of converting peat and moss into vegetable mould: it is apparently simple, easy, and successful. Under the title of resistance of fluids' they give an abstract of Venturi's Experimental Researches,' rather because they have referred to a title of this kind, than that they consider it as adding materially to the information already communicated in the Encyclopædia.

We find in this Supplement a short disquisition on the source of the Nile; and the authors seem inclined to fix it in the western branch, as the more considerable one, and of greater extent. This source no European has visited. We have, however, had occasion to notice, that the origin of every

great river is established, in the common opinion, not from the magnitude of the stream, or the extent of its course, but from some superstitious legend-often from its resisting frost, or its more obvious warmth or freshness, according to the temperature of the country. We see no reason therefore, when we compare the evidence of antiquity, to doubt of Mr. Bruce's having visited what was always supposed, by the Greeks and Romans, to be the true source of the Nile.

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The description of an oil-mill' is very minute and satisfactory; and under the article orchard' we find a good account of M. Germershausen's method of promoting the growth of young trees, and increasing the size and flavour of the fruit in orchards. The oxy-muriatic acid' is inserted, to communicate Mr. Rupp's method of mixing this acid with water, in order to avoid the suffocating steams.

Mr.Salmon's mode of taking off paintings' from walls, announced to the Society for the Encouragement of Arts, &c. is introduced at some length; with several remarks on caustic painting,' from the Philosophical Magazine.

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'Percussion, or the force of percussion,' is but shortly noticed, as the principal observations occurred under the article of impulsion.' The observations of Galileo are added, and some additional ones subjoined; but the author still overlooks what we think the principal circumstance which distinguishes percussion from impulse; viz. the velocity of the impelling power. Of the police of St. Petersburg' there is a sufficiently full account; and on the subject of Perkinism (metallic tractors) the authors are completely sceptical. We have been brought forward by Mr. Perkins as his defenders; but we wish to decline the office. We only pointed out one view of the subject, in which some effect might be produced; and in this view an effect of the same kind might have been produced by Dr. Haygarth's painted wood.

The analysis of Kant's 'critical philosophy' is very valuable, and particularly so, as no intelligible account of it has heretofore appeared in English. We promised an abstract, but could only advance a very little way, from want of skill to comprehend it. At present the analysis needs not be copied, as it is too extensive. We would rather refer to the volume before us, than attempt to abridge it, as the account will not be found very difficult, and as, at the same time, the reader may be supplied with some excellent remarks on it by the author, whom we suppose to be Dr. Gleig. The use of phosphorus' internally, from the trials of Leroi, is copied from the Philosophical Magazine; but we see too many marks of imagination in the observations, to trust that author's accuracy; and we agree with the editor in advising that these trials should not be pursued by the cautious physician.