Separated stable isotopes of Ni have been used to assign a 67-kev maximum energy beta-emitter which decays with an 85-yr half-life to ${\mathrm{Ni}}^{63}$. ${\mathrm{Ni}}^{59}$ was found to decay by $K$ electron capture with a half-life of 7.5×${10}^4$ yrs.

• Received 28 September 1950

DOI:https://doi.org/10.1103/PhysRev.81.391