Lectures de Potentia Restitutiva, or of Spring

Bodies do not immediately touch each other, but permit the mixture of the other heterogeneous original: "Heterogeneous"; meaning diverse or consisting of different kinds of particles fluid near the Earth, which serves to communicate the motion from particle to particle without the immediate contact of the vibrations of the particles.

All solid bodies retain their solidity until, by other extraordinary motions, their natural or proper motions become intermixed with other differing motions. Thus, they become a bulk of compounded motions, which weaken each other's vibrative original: "Vibrative"; relating to the internal oscillation of particles motions. So, although the similar parts do participate in each other's motions—whereby they endeavor to join or keep together—they also participate in a heterogeneous motion, which endeavors to separate or keep them asunder. According to the prevalence of one or the other, the body is more or less fluid or solid.

All bodies whatsoever would be fluid were it not for the external heterogeneous motion of the ambient original: "Ambient"; the surrounding environment or medium.

And all fluid bodies whatsoever would be unbounded, and have their parts fly from each other, were it not for some prevailing heterogeneous motion from outside them that drives them more powerfully together.

Heterogeneous motions from without are propagated within the solid in a direct line if they hit perpendicular to the superficies original: "superficies"; the surface or outer boundary or bounds; but if they hit obliquely, they move in ways not direct, but different and deflected, according to the particular inclination of the body striking, and according to the proportion of the particles striking and being struck.

All springy original: "springy"; referring to elasticity bodies whatsoever consist of parts thus qualified: that is, of small bodies endowed with appropriate and peculiar motions. From this, every one of these particles has a particular bulk, extension, or sphere of activity which it defends from the ingress of any other encompassing heterogeneous body while