Lead isotopes

Abstract

The magneto-optic method shows that lead has sixteen isotopes of probable mass and order of abundance 208, 206, 207, 205, 212, 210, 204, 202, 203, 211, 201, 209, 216, 215, 214 and 213. All sixteen isotopes of lead were found in C.P. uranium and thorium salts. 206, 210, 202 and 214 predominated in uranium salts, while 208, 216, 204 and 212 predominated in thorium salts. The differential time lag varies directly with the weight of the isotopes of a given element. The amount of isotope present is some unknown inverse function of the concentration necessary to read its minimum so that the order of appearance of minima gives the order of abundance but not the relative abundance of isotopes. The order of abundance of isotopes is also given by the amount of rotation of the analyzing nicol necessary to extinguish their minima. © 1933 The American Physical Society.