Protons have been observed from the bombardment of titanium by Th C' alpha-particles. They are probably due to the reaction ${\mathrm{Ti}}^{48}$+${\mathrm{He}}^4$→${\mathrm{V}}^{51}$+${\mathrm{H}}^1$. Three groups of protons are found corresponding to nuclear energy change [$Q$] values of + 1.10, 0.00 and -3.63 Mev. The separation of the last two groups is abnormally great. Combined with Dempster's value for the mass of ${\mathrm{Ti}}^{48}$, the results lead to a mass of 50.9598 for ${\mathrm{V}}^{51}$.

• Received 30 June 1938

DOI:https://doi.org/10.1103/PhysRev.54.408