A molecule, therefore, may consist of any number of atoms of the same element, or may be formed of the union of the atoms of two different elements. In the preceding article we have learned that the atom of hydrogen or carbon, however, is divisible, at least theoretically if not experimentally, as we came to the conclusion that all atoms are composed of infinitesimal aetherial atoms, which are synonymous with atoms of electricity. Whether we shall ever be able to experimentally prove the existence of such an atom remains to be seen, though Dr. Larmor states that the atomicity of electricity is coming within the scope of direct experiment; while the researches of Professors Crookes and J. J. Thomson have undoubtedly given direct evidence of the existence of corpuscles, which are part of the atoms of the various elements. When we try to conceive, however, of the manner in which the various elements can be formed from one primary medium, that is, the Aether or electricity, we find it difficult to arrive at a simple physical conception of the process involved. We are indebted to Professor J. J. Thomson for what is practically the only simple physical conception of the method in which various elements may be formed from that medium, which gives unity to the whole of the universe. In the Adams Prize Essay of 1883 Professor Thomson indicated a theory based on the vortex atom (Art. 43) which satisfactorily accounted for the various laws which governed gaseous matter, and also showed how the varied chemical combinations might be physically conceived as being produced from one primary medium. In this theory we have to conceive of the vortex atom as possessing a hollow core, while in our conception of an aetherial atom (Art. 43) we conceived it as being more of a spherical or globular form than ring-shaped. We have, then, to consider the atom of any element as being composed of a vortex ring of various thickness, the thickness of the ring being an indication of its atomic weight. Each vortex ring must also be conceived as itself being composed of a number of aetherial atoms, or atoms of electricity, the number of such atoms being proportionate to the respective atomic weights of the various elements. Dr. Larmor suggests that a vortex ring may have this constitution in his work on _Aether and Matter_. According to Professor J. J. Thomson, then, any vortex ring, which we have supposed to be constituted of aetherial atoms, or atoms of electricity, may unite with any other vortex ring, thus producing a vortex ring of double density, which would possess double the electricity of the unit vortex ring. If we united three vortex rings, then the result would be an atom of threefold the density and strength of the unit vortex ring.