Samuel Tolver Preston

“ When two masses (or molecules) are gradually approached towards each other, instead of the tendency to approach gradually increasing up to a maximum ( as we should expect from the theory) , they begin to repel at a certain distance, and very considerable force is in general required to overcome this first repulsion, when the masses then unite into one. Thus two freshly cut pieces of lead may be made to unite with some pressure, also glass, or various metals, with more or less pressure. ”

“ When this, like every other illogical prejudice to change, comes to be broken down by the light of reason and reflection, there may be just ground for surprise at the previous delay, and at the shallow and unsubstantial character of the theories which so long supplanted rational conceptions of the processes of nature. ”

“ It must be apparent to any reflecting observer, that in physical science we have a vast array of facts accumulated through years of experiment, but a great paucity of causes; or the number of facts known is quite out of all proportion to the number of causes known, these latter being replaced by more or less vague and unsubstantial theories. ”

“ This, therefore, fulfils Le Sage's fundamental idea without the necessity for accepting any of his postulates. We need not accept the scarcely realizable postulates of streams of particles coming from indefinite distances in space (at uniform angles) , each stream moving continuously in one direction; but we can substitute for this the natural conception of the normal motion of the particles of a gas within the range of free path, where, although each particle is continually changing the direction of its motion, yet the general character of the motion of the system as a whole remains unchanged ”

“ He then goes on to explain how the efficacy of the transverse component of the movement in the case of light, and the longitudinal component of the movement in the case of sound, may be accounted for by the diverse structure of the eye and ear. Any inference which is not valid, invariably does some harm; and this idea of a forward movement being propagated in a medium by only transverse vibrations, being almost inconceivable, has [308] naturally led to some incongruous ideas regarding the structure of the aether, in the effort to explain it. ”

“ Since there is nothing occult about the physical media in space, in so far as they differ in no way from ordinary matter excepting in the mere scale or dimensions of their parts, and since it is obviously just as easy to reason of matter of one dimension as of another, any hesitation in entering upon this course of study would be wholly uncalled for ”

“ The part played by heat in effecting chemical combination would seem to consist simply in producing a molecular disturbance, whereby unavoidably some molecules are urged towards each other so as to pass the outer neutral point, which is the necessary preliminary to combination. No doubt, when heated elements combine, the original heat adds itself to the work thus to be derived, as the heat cannot be destroyed, though it cannot increase the work of combination. ”