Note 8 — CONTENTS. (continued 4)

The system of Physics which I have for many years inculcated, in the hope of removing from Philosophy the equivocal word attraction, supposes that space is filled with an elastic medium,—that this medium permeates bodies in proportion to their quantities of matter,—that resistance or re-action takes place between the universal medium of space and the novel arrangements of matter in bodies,—that this action and re-action diverge in the medium of space from the surfaces of bodies,—and that, like all diverging forces, they act inversely as the squares of the distances. That, if there were but one body in the universe, it would remain stationary by the uniform action of the surrounding medium,—that the creation of another body would produce phenomena between them, owing to each intercepting the action of the medium of space on the other, in proportion to the angles mutually presented by their bulks,—that two such bodies so acted upon by an universal medium must necessarily fall together, owing to the difference between the finite pressure on their near sides, and the infinite pressure on their outsides,—that a stone falls to the earth, because, with regard to it, the earth intercepts an angle of 180° of the medium of space on its near or under side; while, with regard to the earth, the stone intercepts but a small proportion of a second,—that these actual centripetal forces are very slight, between such distant bodies as the planets,—and, that the law of the forces is necessarily as their bulks directly, and as the squares of their distances inversely. That the centrifugal forces result from the same pressure or impulse,—that the varied densities of the opposite sides of the masses, as land and water, occasion a uniform external pressure to produce rotation on an axis,—that the action or oscillation of the fluid surfaces, a consequence of the rotation, constantly changes the mechanical centre of the mass, so as thereby to drive forward the mathematical centre in an orbit,—and that this is the purpose and effect of the tides, increased by the action and re-action of the fluid and solid parts. That centripetal and centrifugal forces so created, are necessarily varied by the diverse arrangements of the solid and fluid parts of planetary bodies, as we see in the northern and southern hemispheres of the earth,—and that hence arise the varied motions, the elliptical orbits, and all the peculiar phenomena. Attached as the moderns are to the terms attraction and repulsion, I produce this theory with due deference to their prejudices; and I venture to presume, that, on examination, it will be found to be a fair induction from the phenomena, and also in perfect accordance with all the laws of motion. It accounts for the uniform direction and moderate exertion of the centripetal force towards the largest body of a system; for the mutual actions of a system of bodies, or of many systems, on each other; and for the constantly varying direction of the centrifugal force, by shewing that it is generated within the mass. The term repulsion is even more disgraceful to Philosophy than that of attraction; all repulsion being in truth but a relative phenomenon between at least three bodies; and its most palpable appearance in electricity being but a stronger mechanical action towards opposite surfaces. The local impulses of magnets, and of bodies going into chemical union, are not better explained by Kepler’s gravitating sympathy, than by this doctrine of mechanical interception; but, I have no doubt that the former of these will, in due time, be traced to the difference between the rotary motion of the Equatorial and Polar regions; and the latter to some laws of the atomic theory, arising out of the shape and arrangement of the component particles, with reference to those of surrounding bodies. Return