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Chriflianity, if a proper article for a work of this kind, needed not to have been extended through several pages, beside a variety of details under the respective words Popery, Calvinisin, Methodism, Presbyterianism, &c. But it is absurd to spend a number of pages on an historical and geographical account of Hell, at the end of which the reader is referred to the word Elyfi:um. This reference to contraries, however, frequently cccurs; as Cierg), fee Laily; Drink, see Food; at the end of the long treabile of Fire we are again sent to Hello
Among other marter, foreign to either the arts or sciences, we may juftly rank the following: 'Burning-buss, that bush wherein the Lord appeared to Moses,' with the substance of that chapter in Exodus where the transallion is recorried. Beard, che hair on the chin, fee Hair. Turning to Hair, we find a long treatise about it, and at length are referred 10 the word Peruke, which however does not occur in the book.
A minute examination of every article in a production of this kind, is a talk which we never proposed to ourselves, and which we are sure our learned Readers would not require at our hands : yet, considering the nature of the work, its price, and the promises made in the Preface, we have been induced to give it as much attention as perhaps it deserves, in order to fulfil, to the utmost of our power, the obligation we are under to the Publis, of pointing out the merits or faults of literary performances, especially such as are so extremely voluminous, and rated so highly as the present. The extensive plan of this Dictionary is one of its greatest faults; and we are persuaded, that were this enormous work divided into a number of smaller ones, imperfect as the matter is, it would be more useful to the Public, and more advantageous to the proprietors. There are some parts of it which we must acknowledge to be well executed; yet the whole is of too great a bulk, as the compilers themselves have evidently experienced; for the first volume contains only three fourths of the letter A, and the tenth S, T, V, U, W, X, Y, Z, beside a copious Appendix and Index. This circumstance alone Thews the inequality of the work, and how much the compilers wished to finish what they soon found was likely to extend its bounds too far.
In reviewing so large a work, we think it our duty to say something concerning the manner in which it is printed. To enumerate all the typographical errors ihat occur, even in the articles we have perused, would be a laborious talk; and the many inftances of negligence are evident marks of halte ,and inaccuracy. The continuing to'number the pages from the beginning of the work to the end, through the whole ten huge volumes, is unusual. The Editor however has adopted an excellent cons trivance, which shows his fk ll in the bibliopolian art. Although
the pages are numbered from the beginnirg to the end, yet the leveral creatifes which we have mentioned are paged separately. For instance, Music, which comes in after 5264, is paged 1, and the numeration goes on to 60, where Music ends, and the page after is 5265; so that the treazife may be taken out of the Di&ionary, and not missed, and sold as a book by itself; a complete treatise on Music, on a prefixed title-page, being the only thing wanted to render it a perfect book. The copperplates, which are three hundred and twenty-three in number (though the title page only says above two hundred'), are, in general, poor engravings; in many instances they are bad representations of the originals; and in some, particularly the botanical ones, material faulis occur.
Upon the whole, we will that Arts and Sciences had some berrer support than they are likely to receive from the present performance; yet for many obvious purposes, the Encyclopædia Britannica may be useful, and afford much instruction in its prelent state, however, it may, not unapely, be compared to a great garden, abounding with choice trees and plants, but all over-run wird weeds.
R--m. Art. V. An Elay on the Investigation of the first Principles of
Nature : together with the Application thereof to solve the Phenomena of the Physical System. Part I. Containing a new philosophical Theory, &c. By Felix O'Gallagher. 8vo. gs. Boards.
Murray. 179; IT HIS work is delivered in the form of lectures, beginning
with the first principles of philosophy, and laying down a theory and rules for physical investigations. The first and fecond sections consist of what the Author calls the first principles and fundamental axioms of natural philosophy, neceffary observations, and physical definitions and propositions : but we cannot pretend to give a particular account of these,' which would take up too much room.
In the 3d fear. the Author compares the Newtonian rules of philosophizing, as given by Martin in his Philosophia Britannica, vol. i. p. 2. ; with his own rules, or propositions, delivered in the two former sections, whose sole tendency, he says, “is to form accurate distinctions, which is in a great measure the business of philosophy.'
• The spirit of Newton's rules, on the other hand, is to fimplify, and, if possible, to deduce all effects from the same cause : which me. thod, however just, was dangerous in its application, as it induced his followers not to search after, por admit more principles than one, although more manifestly display themselves in nature.
Two examples will shew the different tendencies of both methods.
• Conformably to the spirit of the Newtonian rules, it is said (hy Mr. Martin) in the general conclufion, that all bodies confift of one
and the same kind of matter, and that all their varieties proceed from various modifications of the same particles. It is also concluded, in the explanation of the third rule, that gravity, vis inertiæ, &c. are the properties of all bodies. But our rules not only render os more circumspect in adopting such conclusions, but even induce us to reject them. For as to the first, we know that the immediate and phyfical causes of all material effects are themselves material; that therefore the cause of heat, light, and expansion, or the substance, producing those effects, is material. Again, as one physical agent, or material cause, cannot produce two contrary effects; therefore attraction, which draws together, and expansion, which separates, cannot proceed from the same cause. Consequently, as these two operations are seen to obtain in material nature, they have two diltinet material causes, whose effences and propensities are opposite; we therefore disallow the general conclufion above cited from Martin, and pronounce that experience exbibits, at least, two kinds of matter in nature: for opposite propenfities must arise from different essences, i.e. different fubitances, consequently from different principles.
• Let us now, according to the same method, 'examine the second affertion we have quoted, to wit, “that vis inertiæ, with the other properties there enumerated, is common to all bodies.”_' Certain it is, that a strong centripetal force acts upon bodies throughout the universe. It is also allowed, that there is also another power in nature, namely, that of fire or light, which expands or dilates bodies, separating their parts with a centrifugal force. This principle of expanfion, according to Boerhaave, is so universal, that there is not a body, or space in nature, which has not its fires, though sometimes latent until excited --Wherefore light or fire, the principle of the centrifugal force, being a material substance, we also conclude, that the centripetal force, which is equally powerful in producing material effects, also arises from a material substance.
• There are, therefore, in nature, cwo material agents, of prodi. gious efficacy, and of opposite propensities or tendencies to act; these cannot be called inert, because they have in themselves a power of motion and of action, which gives motion to inert matter, and which produces the operations of nature. We must therefore set limits to the property of inertness, which the present generalizing method of philosophizing has rendered too universal.'
So far our Author: but what Newtonian philosopher ever denied the efficacy of gravity, and fire ? As to the inertness of matter, which Mr. O'Gallagher makes the subject of his second lecture, he calls the universality thereof, an unreasonable and false fuppofition; because matter is defined by philosophers to be a substance extended, solid, and perfectly inactive, considering how far this definition is juft, he allows it extension and solidity, but not inactivity, for then, he says, we could not be sensible of its existence; at least we should have no sensation of those bodies which are beyond the reach of feeling : " for such diftant bodies only affect our organs, which are of a neutral passive nature, either by the action of an effluvium, or of some intervening medium. Now, our corporeal organs being matter, can only be affected by another material substance, and this cannot be inert as it acts upon them : the matter therefore which gives sensation of diftant bodies cannot be inert.'
But we apprehend that this metaphysical mode of argumentation only misrepresents the meaning of the Newtonian philosopbers. No sooner is matter in motion, than we suppose they will allow that its inactivity is at an end. Our Author, however, goes further, and will not allow it to be inert even at reft. We cannot pretend to transcribe the whole of what he says upon this subject, or even to abridge it, but must refer to the book'ita felf. He objects, at p. 80, to the usual proof of inertness drawn from the motion of bodies on horizontal planes; and, at p. 83, proposes the following teft, which, he says, admits of mathematical demonstration ; we therefore suppose that he looks upon it as his principal argument.
"" Let a box or canister, wherein different weights may be put oca cafionally, be suspended like a pendulum, at different lengths proportioned to the weights contained ; if you allow a foot from the point of suspension to the centre of the box, when a pound is in, allow twenty feet for twenty pounds, so that the pendulous lengths thall be as their weights. Let an hook or wire be inserted at the central part of the box or canister, to which a thread is fixed that will stretch horizontally over a free pulley; and at the other end of this thread let a scale be joined, to receive the weights or grains that will draw the box aside from the vertical line of free fuspension; then note the weights or grains that will draw the central part of the box, when loaded with each weight, the length of an inch, or even the tenth of an inch from that vertical line, and you have the force of inertness * in each weight, expressed by the grains that move it from that line : for whatsoever moves the body overcomes its vis inertiæ.
· Now (p. 86.), when these experiments are accurately made, and every circumstance considered, and duly valued ; if the difference of forces to stir these two bodies, one of a pound, and the other of twenty pounds, whose difference is nineteen pounds, is found to be but a few grains, which may be occasioned by the resistance of the air, or such extrinsic causes, vis inertiæ may be considered as the same in all bodies, and therefore to be neglected in every computation, being a constant invariable quantity in all heavy bodies, great and small, which admits of no various degrees, increment, or force.'
But will not the Newtonian philosophers say that our Author is here combating a mere chimera, a creature of his own imagination, and that they have no other idea of the vis inertia, but that the least imaginable impulse, or accelerating force, will overcome it in free space? It is true, they will say, that they supe pose it greater as a body is greater, and for this reason, if a heavy perfectly smooth body be laid upon a finely polished borizontal plane, any heavy body connected with it by a string paffing over a pulley at the edge of the plane, and hanging freely,
may, abstracting from friction, move it, nay draw it to the end of the plane : but that the greater the body or weight is that hangs freely, the sooner will it perform this, yet still in all cases the descending weight would move flower than it would do if the string were cut and it were liberated from the body that moves along the plane ; consequently the vis inertic acts as a retarding force to the descending body; and this body being supposed given, the greater the other body is, the greater is the retarding force, and is therefore different in bodies of different sizes or quantities of matter. As to this gentleman's proposed demon, ftrative experiment, they will shew that it can be of no use or force at all. For any impulse or force whatever acting horizontally upon the body, will be sufficient to draw it from the perpendicular, and the instant it is so drawn, gravity will begin to act upon it, and its own weight and the different positions of the string are necessary to be taken into consideration, in order to determine how far it can be drawn from the vertical line; consequently, the experiment must be very ill contrived to determine with precision the vis inertiæ.
His third and fourth lectures are on the elastic principle in bodies, which he fhews to exist in vegetable, animal, and foffil bodies, in fire, air, and water. He endeavours to exhibit the elastic substance separately, to Mew iis uses in nature and mode of operation. He takes into consideration a heap of vegetables 20 hundred weight, which is by fire reduced in a small heap of faline ashes, not 50, perhaps not 20 pounds weight, which when depurated, by walhing, to pure pale alhes, will be much less : and perhaps, says he, 10 pounds of such a refiduum would not remain, if the heap originally consisted of paper, or linen. He asks what is become of the weight or gravity of the heap, when its alhes retain not the hundredih part thereof?
· Nineteen hundred weight, he continues (p. 157-), has disappeared ; fhall we therefore conclude, that all this weight has been carried off by smoke and Aame? This seems improbable; for, whatever be the material cause of gravity, certainly it has not a tendency to ascend, being convergent and centripetal. On the other hand, Aame has ever a contrary propensity, viz. to rise and expand; and smoke, which we find to be the nascent form of Aame, is analogous thereto, and should have the same tendency, though in a lower degree ; consequentiy, when fire dissolved the cohesion of the body, and separated its elements from each other, -each pursued the pro. pensity peculiar to its nature; the elastic matter, released from its confinement, fed into the atmosphere, its proper reservoir ; and the matter of gravity must have sunk with native propensity towards the centre of the earth, a small part of it only still remaining with the alhes and salts on the surface. And as essences must ever accompany their peculiar subitances, the elastic matter in its fight, carried off the elasticity, fmell, taste, and other lively qualities peculiar thereto, along with the oils and spirits, on which, according to all chemists,