means of extinguishing flame. With regard to the late French invention, which has so much alarmed some gentlemen of distinguished rank, viz. the improved diving machine, and the apparatus affixed, which is designed to blow up a line-of-battle ship, it belongs to this head. We think it by no means impossible; but may add, that the divers must necessarily be, in every instance, the victims; and the whole plan will be unsuccessful, unless the ship stand as steady as a rock, and unless, as action and re-action are equal, there be a very small depth of water under the ship. At any rate, however, there will be the same impediments to this plan, as to firing redhot balls, or fighting under false colours.

The article of friction' is greatly improved, and that of Galvanism,' we believe, wholly new. This science has, however, been largely illustrated since the publication of the Supplement; and these illustrations it could not comprehend. Had the compilers been in possession of the more extensive views of later authors, they would not, we suspect, have denied the connexion of Galvanism with electricity; and had this connexion been established, it probably would have much influenced their opinion respecting the system of Epinus.The articles Gibraltar and the Cape of Good Hope' are improved by useful additions, lately communicated to the public. In that of St. Domingo,' we find what may be styled a digression on the subject of the slave-trade, and the objects of the benevolent-but, in some respects, mistaken-society, entitled the Friends of the Blacks.' Whatever be the merit of the design, they, as well as the modern advocates of liberty and equality, have mistaken their ground. Neither the French nor the Blacks were prepared for emancipation. While we say this, however, not to break the subject, we shall remark, that the observations on Jacobins' and the Illuminés in the present volume are equally unjust and unfounded. That the Encyclopædists were deists, and in several instances atheists, we will admit; but it was vanity only which led them to destroy Christianity, without any design of raising themselves into a superior rank of mortals. Their follies and their vices were too well known; and Frederic, whom they flattered into an oracle on a subject which he did not understand, soon left them, when he perceived the connexion between the destruction of religion and that of social order. We allow the connexion,' but deny that the abolition of the latter was any part of their design; and we deny it, not only from a view of their conduct, but from their dispositions. Not one of the whole set-the reader may supply a more opprobrious appellation-was capable of a deep design, nor of the conduct of such, if projected by another. Voltaire's profoundest schemes were planned to cheat the booksellers; and Diderot

never soared higher than to overreach Catharine in the sale of his boasted library. With respect to the Illuminati and, the Freemasons, we have already offered our opinion. We cannot, indeed, contradict what authors of credit-for such we esteem at least professor Robison-have asserted; but they have never proved the connexion between these mystical sects and the late revolution. The whole is easily resolved without the aid of mysticism. We personally knew many of the original actors in the revolution, and were convinced of the purity of their views; but they were obliged to employ a force which they could not afterwards controul; and the combined power of the mob, which they used as an instrument, felt their own influence, when collected in the hall of the Jacobins. Weishaupt, in his new society, might have adopted the various degrees of honour here enumerated from the abbé Barruel or professor Robison; but the Jacobins of France were never to any extent or great degree under the influence of this society; and the frantic restless spirit of innovation was no-where, at one period, more alive than in this country. Why may not then similar causes have had similar effects in others, whatever may have been the doctrines of this mystical union? With respect to Freemasonry, some new ordinances may have been added; but the Masons of England know that they have not been received in their lodges; nor are there, in any order of society, better men, or better subjects. The world was ripe for innovation-unfortunately innovation has not amended their state, and the little inconveniences which roused the spirit of resistance have been exchanged for misery, poverty, and contempt. Let even the individuals of France recount their gains, and soberly affirm what they have obtained in exchange for the destruction of their marine and the loss of their commerce-years of anarchy, and, perhaps, ages of restless doubt and suspicion. In this progress we have overlooked, though not without design, an excellent article on dynamics,' chiefly that we may unite it with one of equal ability-the last in the present volume of the Supplement impulsion. This subject we meaned to have examined at length, but find it impossible within any reasonable compass. In general we can freely commend it; yet, when the writer considers impulse as pressure,' the idea requires some modification. It must be, indeed, ultimately resolved into pressure: but, as impulsion, it is pressure with momentum,, and actuated, perhaps, by peculiar laws. Had we engaged fully, as we purposed, in this inquiry, we should from these principles have introduced some modifications in his views of the conservatio virium vivarum. We admit that the author has given the first demonstration of the theorem, and we admit also that it is the property of Newton. Indeed, in each article, he has shown himself laudably zealous for our

countryman's fame, and, without the petulance of a partisan, has with manly dignity asserted his rights. Were we hypercritical, we might remark that he has been rather too minute in his distinctions, and his introduction to the article of 'dynamics but when we reflect that the pages of his dictionary have heretofore employed as many volumes, when we consider that his luminous view of the subject gives a full, and at the same time correct, sketch of the subject, we may pardon what appears to us a little prolixity; and we the more readily pardon it, as we accede to the application in the second article of impulsion.

We regret that our author has not explained, more pointedly and comprehensively, a position which we think very well established, viz. that bodies, apparently in contact, are really not so, and that resistance is not owing to the immediate impulse of the particles of matter on each other. Our opinion we have often had occasion to explain. We shall add some of our author's observations, but cannot admit the consequence which the draws, that this doctrine excludes the supposition of an interposed fluid. We think it rather establishes its existence, since otherwise an effect appears to take place without a

cause.

2

It is hardly necessary now to say, that all attempts to explain gravitation, or magnetism, or electricity, or any such apparent action at a distance by the impulsions of an unseen finid, are futile in the greatest degree. Impulsion, by absolute contact, is so far from being a familiar phenomenon, that it may justly be questioned whether we have ever observed a single instance of it. The suppo

sition of an invisible impelling fluid is not more gratuitous than it is useless; because we have no proof that a particle of this fluid does or can come into contact with the body which we suppose impelled by it, and therefore it can give no explanation of an action that is apparently e distanti.

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The general inference from the whole seems to be, that, instead of explaining pressure by impulse, we must not only derive all impulse from pressure, but must also ascribe all pressure to action from a distance; that is, to properties of matter by which its particles are moved without geometrical contact.

This collection of facts conspires, with many appearances of fluid and solid bodies, to prove that even the particles of solid, or sensibly continuous bodies, are not in contact, but are held in their respective situations by the balance of forces which we are accustomed to call attractions and repulsions. The fluidity of water under very strong, compressions (which have been known to compress it of its bulk), is as inconsistent with the supposition of contact as the fluidity of air is. The shrinking of a body in all its dimensions by cold, nay, even the bending of any body, cannot be conceived without allowing that some of its ultimate unalterable atoms change their distances from each other, The phenomena of capil

lary attraction are also inexplicable, without admitting that particles, act on others at a distance from them. The formation of water into drops, the coalescence of oil under water into spherical drops, or into circular spots when on the surface, shew the same thing, and are inexplicable by mere adhesion. In short, all the appearances and mutual actions of tangible matter concur in showing, that the atoms of matter are endowed with inherent forces, which cause them to approach or to avoid each other. The opinion of Boscovich seems to be well founded; namely, that at all sensible distances, the atoms of matter. tend toward each other with forces inversely as the squares of the distances, and that, in the nearest approach, they avoid each other with insuperable force; and, in the intermediate distances, they approach or avoid each other with forces varying and alternating by every change of distance.' Vol. i. P. 804.

We do not perceive that this difference in opinion affects the author's conclusions. Had we time, we could show that it only influences the language; if it be once allowed (as it must be per hypothesin) that this interposed fluid penetrates the most solid bodies, resisting only in consequence of its relation (we dare not say affinity) to different substances.

From all that has been said, we learn that physical or sensible contact differs from geometrical contact, in the same manner as physical solidity differs from that of the mathematician. Euclid speaks of cones and cylinders standing on the same base, and between the same parallels. These are not material solids, one of which would press the other out of its place. Physical contact is indicated, immediately and directly, by our sense of touch; that is, by exciting a pressure on our organ of touch when it is brought sufficiently near. It is also indicated by impulsion; which is the immediate effect of the pressure occasioned by a sufficient approximation of the body impelling to the body impelled. The impulsion is the completion of the same process that we described in the example of the magnets; but the extent of space and of time in which it is completed is so small that it escapes our observation, and we imagine it to be by contact and in an instant. We now see that it is similar to all other operations of accelerating or retarding forces, and that no change of velocity is instantaneous; but, as a body, in passing from one point of space to another, passes through the intermediate space; so, in changing from one velocity to another, it passes through all the intermediate degrees without the smallest saltus.

And, in this way, is the whole doctrine of impulsion brought within the pale of dynamics, without the admission of any new principle of motion. It is merely the application of the general doctrines of dynamics to cases where every accelerating or retarding force is opposed by another that is equal and contrary. We have found, that the opinion, that there is inherent in a moving body a peculiar force, by which it perseveres in motion, and puts another in motion by shifting into it, is as useless as it is inconsistent with our notions of motion and of moving forces. The impelled body is

moved by the insuperable repulsion exerted by all atoms of matter when brought sufficiently near. The retardation of the impelling body does not arise from an inertia, or resisting sluggishness of the body impelled, but because this body also repels any thing that is brought sufficiently near to it. We can have no doubt of the existence of such causes of motion. Springs, expansive fluids, cohering fibres, exhibit such active powers, without our being able to give them any other origin than the FIAT of the Almighty, or to com prehend, in any manner whatever, how they reside in the material atom. But once we admit their existence and agency, every thing else is deduced in the most simple manner imaginable, without involving us in any thing incomprehensible, or having any consequence that is inconsistent with the appearances. Whereas both of these obstructions to knowledge come in our way, when we suppose any thing analogous to force inherent in a moving body solely because it is in motion. It forces us to use the unmeaning language of force and motion passing out of one body into another; and to speak of force and velocity as things capable of division and actual separation into parts. The force of inertia is one of the bitter fruits of this misconception of things.' Vol. i. r. 805.

We greatly regret that we cannot follow our author more minutely. We have seen nothing more clear, more comprehensive, or more satisfactory, on this intricate subject.

The lives, in the remainder of this volume, are numerous and interesting, and form a very valuable part of the present collection. They are, in general, written with exact judge. ment and minute discrimination. We shall notice some of the more important.

The life of Sir David Dalrymple,' better known by his title of Lord Hailes,' is an excellent one, truly discriminative of his peculiar talents. Where so much commands our respect, we scarcely dare to hint at a fault; but perhaps we may ask, whether the accuracy of his judgement kept pace with the undeviating excellence of his heart? We should be sorry by such a question to offend his friends, or do an injury to his memory. His knowledge was extensive-his publications truly valuable; nor perhaps do they contain a line which he would now wish to erase,

There are some curious particulars of the frantic and suffering Damiens,' which show that the warmest enthusiasm is not peculiar to modern Frenchmen. Desault' was a surgeon of considerable abilities, and one of the innocent martyrs of the revolution. His terrors at least for the idle story of his being poisoned himself, because he would not assist in the crime of poisoning the son of the unfortunate Louis, is absurd, since the jailors could more easily have destroyed the child than the surgeon-overcame him; and he died, like some other excellent men, from his apprehension of the villains who then assumed the regal power. Of Diderot' the account is very