ABSTRACT
In this chapter, the authors are concerned with theories designed to explain the properties of bodies, starting from first principles. To explain the familiar fact of action at a distance, the people are offered a hypothetical medium with properties different from those of ordinary matter. Smith wrote of Graham-as might have been said of Davy-that 'in all his work the people find him steadily thinking on the ultimate composition of bodies'. What is unexplained in Graham’s theory is how the atoms retain their original motion unchanged. It seems probable that his hypothesis resembles the theory of gases of Newton or Davy; the particles are not in rapid translational movement, always colliding and gaining or losing energy at each impact, but are simply vibrating with different intensities, and do not come into contact with one another.
