ONE of the present aims of science is to explain the properties of matter in terms of the properties of its basic constituents, the proton and the electron.
The problem of the numerical electronproton content of the atom of any element has been solved. The physicist and chemist are now engaged in attempting to arrange protons and electrons into combinations such that the fundamental properties of the protons and electrons, expressed, for example, by a modified inverse square law of attraction, give the resultant properties of the atoms of the various elements.
One of the most important of the resultant properties is the field of force which gives rise to the attraction existing between atoms of the same or of different species. The result of this attraction is the formation of molecules with a consequent neutralization of the greater part of the field of force. Comp!ete neutralization never occurs.
The molecule, as such, is left with a residual force of attraction, and this paper deals with some of the experimental methods by means of which the influence of these forces can be detected and their relative magnitudes estimated.
The subject of molecular forces is a large one and in this case is confined to the narrow field of investigation in which experi-* Presented at a meeting held Thursday, March 6, 1924.