The theory of the author is founded on the two following propositions, namely, that 1. Every atom of matter consists of an immense sphere of force, varying inversely as the square of the distance from the centre ; this force being attractive at all distances, except in a small concentric sphere, in which it is repulsive. 2. Atoms differ from each other in their absolute forces, or in the extent of their spheres of repulsion, or in both these respects. The author assumes that there are four classes of atoms, the tenacious , the electric , the ethereal , and the aromatic . The existence of the last-named class of atoms he infers from the phenomena of vegetation, the miasmata of marshes, the aroma of plants, various noxious effluvia, the disinfecting property of some bodies, and facts relating to animalcules, and their ova, &c. He regards the two propositions which constitute the great principles of his theory, as presenting, at once, a complete explication of the general attributes of matter and body, with the Newtonian laws of motion, not otherwise theoretically explicable.