That the intra-atomic charge of an element is determined by its place in the periodic table rather than by its atomic weight, as concluded by A. van den Broek (Nature, November 27, p. 372), is strongly supported by the recent generalisation as to the radio-elements and the periodic law. The successive expulsion of one α and two β particles in three radio-active changes in any order brings the intra-atomic charge of the element back to its initial value, and the element back to its original place in the table, though its atomic mass is reduced by four units. We have recently obtained something like a direct proof of van den Broek’s view that the intra-atomic charge of the nucleus of an atom is not a purely positive charge, as on Rutherford’s tentative theory, but is the difference between a positive and a smaller negative charge.