Samuel Tolver Preston

“ We observe that under the principles of the kinetic theory no such supply is necessary, but that all the conditions requisite for gravity may be fulfilled by a medium pervading the visible universe, and which is at rest as a whole ; or the gravific medium within the bounds of the visible universe may be compared to the air within a receptacle, which is, as a whole, at rest; and therefore there is no more waste of the matter producing gravity than if mundane matter did not exist. ”

“ All we require to admit is that the mean length of path of the particles of the medium is at least as great as the very limited range through which gravity has been observed to act ; or, in order to explain all the observed facts, it is sufficient to admit that the universe is immersed in a gas (or medium constituted according to the kinetic theory) the mean length of path of whose particles is so adjusted as to cause the minor or secondary portions of the universe to gravitate towards each other. ”

“ The agent producing gravity must therefore not in any way be looked at (as one might possibly be liable to do at first sight) as representing a prodigious quantity of streams of gross matter flying about, but simply as the quiet imperceptible motion of a relatively very small quantity of excessively finely subdivided matter which produces a perfectly uniform pressure, the energy of each particle by itself being totally imperceptible ”

“ It is necessary to assume that the particles producing gravity are in very close proximity compared with molecules, otherwise the particles would be unable by their motion to produce a perfectly equable pressure upon the molecules of matter. ”

“ Accordingly, as by a given amount of energy in unit volume the energy of each particle is inversely as their number, so by multiplying the particles the energy of each may be made indefinitely small; and therefore the energy transferred to the molecules of matter would be made indefinitely small, or there would be no measurable rise of temperature at all. ”

“ Thus he assumes ".... that not more than one out of every hundred of the particles meets another during several thousands of years ; so that the uniformity of their motions is scarcely ever disturbed sensibly." We now know that, so far from the collisions of the particles among themselves disturbing the uniformity of their motions, this is the very cause which corrects and maintains the uniformity of motion, or preserves the uniformity of motion in opposition to external disturbing causes. ”

“ So with a gravific particle striking a molecule of matter; for mere size makes no difference in the principle. It is therefore not an unnatural thing (but highly probable on independent grounds) that the gravific particles should have their velocities changed at impact against the molecules of matter. The energy of the particle remains unaltered by the impact; only the distribution of the energy in the particle is changed. ”

“ To us it seems that a closer study of the theory only serves to show its [370] many mechanical beauties and extreme simplicity as a means to an end, satisfactory, not only in the absence of any other conceivable cause, but as affording a perfectly rational conception to the mind of the processes by which the effects are brought about. ”

“ Again, the perfectly free passage of light or the waves of aether through a piece of glass, or a wave of obscure heat through a block of rock-salt, also of the magnetic disturbance through all matter, would by itself prove the extremely open structure of matter. ”

“ We say simplicity; for surely we have the ne plus ultra of simplicity, when no postulates at all are required, but the total sum of effects may be said simply to evolve themselves out of pure dynamics. ”

“ In architectural and engineering structure generally we do not observe a solid block formation, if I may so express it, but that open structure which is essential to elasticity and strength. So in molecular architecture, we may not expect to find a mass a solid block, but of open structure, though we naturally cannot see the interstices. ”