Origin of Atmospheric Argon and the Radioactive Decay Constants of Potassium-40

IN a previous communication 1 , it was pointed out that E. Bleuler's and M. Gabriel's 2 estimates of the total half-life and K -capture to β-ray emission branching ratio were probably too high, since they led to an excessive quantity of argon-40 being produced by the surface materials of the earth during geological time. The more recent determinations of the radioactive decay constants of potassium-40 seem to have amply confirmed this view: in fact, if they are correct, the present difficulty is to explain the origin of argon-40 in the atmosphere.