the enrichment of decay products. Strassmann and Ernst Walling developed the rubidium-strontium method of radiometric dating in 1936 and 1937, and Strassmann continued this work in 1942 and 1943. His methods are known as emanation methods, and Strassmann's research in this area was fundamental to the field of geochronology.

"Zur Folge nach der Entstehung des 2,3 Tage-Isotops des Elements 93 aus Uran" ["Following the formation of the 2.3-day isotope of element