The cosmic abundance of lead and uranium have been determined by studying the lead and uranium contents of meteoritic materials. Lead is found to be present to 8× atom/10 000 atoms of silicon, and uranium to 1× atom/10 000 atom of silicon. The new value for lead removes the hump in the cosmic abundance curve in the 206-208 mass region. The relative primordial abundances of lead isotopes of mass 204, 206, 207, and 208 are found to be 1:9.4:10.3:29.2, respectively.
- Received 27 July 1953
- Published in the issue dated December 1953
© 1953 The American Physical Society