New data are presented on the high-energy fragmentation and fission of U, Ag, and Br in nuclear emulsions. The method of investigation is described.

The nature of triple-pronged events involving fission of U with 560-660 Mev protons is discussed.

Data are given concerning fission of U with 300-Mev ${\pi }^{+}$ mesons. The cross section for the fission of Ag with high-energy protons is determined.

• Received 12 July 1957

DOI:https://doi.org/10.1103/PhysRev.109.1779