Angular distributions and kinetic-energy spectra of fragments, and cross sections for fission of ${\mathrm{U}}^{238}$ with 63- to 124-Mev ${\mathrm{C}}^{12}$ ions, have been measured with the use of a silicon $p-n$ junction detector. The distributions have been analyzed in terms of the formation of a compound nucleus and subsequent decay by evaporation of neutrons in competition with fission. The percent fission from each isotope in the evaporation chain has been calculated and the over-all angular distribution estimated with the use of the theoretical curves of Halpern and Strutinski. At the highest bombarding energies, the observed angular distributions were found to be more nearly isotropic than predicted. The mean linear momentum of the fissioning nucleus appears to be less than that of the heavy ion. A possible explanation for these discrepancies is that before the fission event there is competition from reactions in which particles are emitted in the forward direction. The contribution from this kind of reaction is estimated to be of the order of 30% at 95 and 124 Mev. Over the entire range of bombarding energies, the most probable total kinetic energy release is 186±6 Mev. By correspondence this suggests that the fissioning nuclei are californium isotopes. The fission cross section increases from a value of 40 mb at 63 Mev to 2.4b at 124 Mev. The experimental fission cross sections agree well with the cross sections for compound-nucleus formation calculated by use of a square-well nuclear potential with a radius parameter $r_0=1.5\mathrm{}\times {10}^{-13\mathrm{}}$ cm.

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