THOUGHTS ON THE NATURE OF THINGS. . 407 smaller, sometimes greater, he did not see in what manner this going out and in of corpuscles, in re ference to their position in that body, could exist, except inconsequence of an interspersed vacuum, contracting on the compression, and enlarging on the relaxation, of the body. For it was clear that this contraction of necessity was produced in one of three ways ; either in that which we have spe cified, namely, the expulsion of a vacuum by means of pressure, or the extrusion of some other body previously incorporated, or the possession by oodies of some natural virtue (whatever it might be) of concentration and diffusion within them selves. As relates to the extrusion of the rarer body, it is a mode of reasoning that involves us in an endless series of such expulsions. For true it ?s, that sponges and the like porous substances, contract by the ejection of the air. But with re spect to air itself, it is clear from manifold experi ments that it can be condensed in a known space. Are we then to suppose that the finer part of air itself may be thus eliminated by compressure, and of the eliminated part another part, and so on to infinity 1 ? For it is a fact most decidedly ad verse to such an opinion, that, the rarer bodies are, they are susceptible of the more contraction ; when the contrary ought to be the fact, if contraction was performed by expressing the rarer portion of the substance. As to that other mode of solution, namely, that the same bodies without farther al teration undergo various degrees of rarity and density, it is not worthy of elaborate attention. It seems to be an arbitrary dictum, depending on no cognisable reason, or intelligible principle, like the generality of the dogmas of Aristotle. There remains then the third way, the hypothesis of a vacuum. Should any one object to this, that it appears a difficult and even impossible supposi tion, that there should exist an interspersed vacu ity, where body is everywhere found ; if he will only reflect calmly and maturely on the instances we have just adduced, of water imbued with saf fron, or air with odours, he will readily discover that no portion of the water can be pointed out where there is not the saffron, and yet it is mani fest, by comparing the saffron and the water pre vious to their intermixture, that the bulk of the water exceeds by many times the bulk of the saf fron. Now, if so subtile an interspersion is found to take place in different bodies, much more is such interspersion possible in the case of a body and a vacuum. Yet the theory of Hero, a mere experimentalist, fell short of that of the illustrious philosopher, Democritus, in this particular point, namely, that Hero, not finding in this our globe a vacuum coa- cervatum, denied it, therefore, absolutely. Now, there is nothing to hinder the existence of a com plete vacuity in the tracts of air, where there are, undoubtedly, greater diffusions of substances. And let me give this once the admonition, that, in in. > .in.l similar investigations, none be over* powered or despair, herau.se i. f tin- surpassing subtiliy of nature. Let him reileet that things, in their units and their aggregates, are equally mastered by calculation. For, one expresses or conceives with the same facility a thousand yeara and a thousand moments, though years are com posed of multitudes of moments. And, a^ain, let no one think that such studies are matter of speculative curiosity, rather than connected with practical effects and uses. For, it is observable, that almost all the philosophers and others, who have most intensely busied themselves, who have probed nature to the quick, as it were, in the pro cess of experiment and practical detail; have been led on to such investig ttions, though unfor tunate in the mode of conducting them. Nor does there exist a more powerful and more certain cause of that utter barrenness of utility which distinguishes the philosophy of the day, than its ambitious affectation of subtilty about mere words or vulgar notions, while it has neither pursued nor planned a well supported investigation of the subtilty of nature. Of the equality or inequality of Jltcr-iv, or seminal Particles. The theories and maxims of Pythagoras were, for the most part, better adapted to found a pecu liar order of religionists, than to open a new school in philosophy, as was verified by the event. For, that system of training prevailed and flourished more under the swaj of the Mani- chaean heresy and Mahomedan superstition, than among philosophic individuals. Notwithstanding this, his opinion that the world was composed of numbers, may be taken in a sense in which it goes deep into the elementary principles of na ture. For, there are (as indeed there may be) two doctrines with respect to atoms or seminal particles; the one that of Democritus, which ascribes to atoms inequality one to another, figure, and, in virtue of figure, position; the other, that of Pythagoras, perhaps, which affirms them to be all precisely equal and alike. Now, ho who ascribes to atoms equality, necessarily makes all things depend on numbers; while he who clothes them with other attributes, admits, in addition to mere numbers, or modes of assem blage, certain primitive properties inherent in single atoms. Now, the practical question colla teral to the theoretical one, and which ought to determine its limits, is this, which Democritus, proposes: whether all things can be made out of all 1 To me, however, this question appears not to have been maturely weighed, if it be under stood as referring to an immediate transmutation of bodies. It is, whether all things do not j>as* through an appointed circuit and succession <>
