Two new radioactive isotopes have been found, ${\mathrm{Os}}^{185}$ produced by a $\mathrm{Re}\mathrm{}(d,2n)\mathrm{}$ reaction and ${\mathrm{Ir}}^{190}$ produced by $\mathrm{Ir}\mathrm{}(n,2n)\mathrm{}$ and by $\mathrm{Os}\mathrm{}(d,n)\mathrm{}$ reactions. The following characteristic values have been assigned to the isotopes in Re, Os, and Ir: The 17-day osmium activity has not been found. Chemical separations were carried out on the rhenium and osmium bombardments.

• Received 27 November 1946

DOI:https://doi.org/10.1103/PhysRev.71.288