The photometry of mass-spectra and the atomic weights of krypton, xenon and mercury

Abstract

The evolution of matter is one of the most attractive and important problems in physics. In the case of all elements other than those of radioactive origin experimental data from which we may hope for light upon it are few and difficult to apply. One possible line of approach is the study of the relative abundance of different types of atoms. Here the problem can be attacked in two stages, the relative abundance of chemical elements in all matter available for analysis and the relative abundance of isotopes in each chemical element. The first of these has received the continuous attention of chemists for many years, and more and more reliable estimates appear from time to time embody­ing the results of thousands of the most painstaking analyses of rocks and other material terrestrial and meteoric. The great difficulty is in defining a fair sample. The Earth taken as a whole may possibly be such, but since the vast mass of its interior is inaccessible, and processes of physical and chemical segregation of the elements have been going on presumably ever since it separated from the Sun, it cannot be regarded as a satisfactory one. We can only combine the analyses of the lithosphere, the hydrosphere and the atmo­sphere in what seems to be the fairest way. If we do this, among the many inferences we may draw is at least one which adds further uncertainty. It has been pointed out that the scarcity of the inert gases is quite abnormal and suggests that even our planet as a whole may not be a fair sample after all.