An investigation of the ${\mathrm{He}}^3$/${\mathrm{He}}^4$ abundance ratio in helium extracted from the atmosphere, gas wells and a number of minerals has been made. Wide variations in this ratio are observed indicating that a more comprehensive program would be well worth while. ${\mathrm{He}}^3$ is observed in all sources of helium except radioactive minerals. This suggests the possibility of a primordial source as well as more recent sources for this isotope.

• Received 27 August 1948

DOI:https://doi.org/10.1103/PhysRev.74.1590