Eighty long range alpha-particles coincident with ${\mathrm{U}}^{235}$ fission have been observed in photographic plates. There is a tendency for the alpha-particles to emerge with greatest energy at an angle slightly greater than 90° from the heavy fragment. In accordance with previous observers, it is found that most alpha-particles emerge approximately perpendicular. It is also found that the majority form an angle slightly obtuse to the heavy fragment. The energy of the alpha-particles is found to be derived largely from the kinetic energy of the fission fragments. The alpha-emitting fissions have approximately the same mass ratio as do normal fissions.

• Received 10 January 1949

DOI:https://doi.org/10.1103/PhysRev.75.1339