The reducibility of a number of ions by dry hydrogen was studied in various glass compositions. Reduction temperatures with dry hydrogen were about 75° C, lower than with wet hydrogen. The glasses contained 5.0% of Sb2O3, Bi2O3, or PbO or 0.1% of Ag2O. In all of the glasses, silver ions were reduced at lower temperatures as basicity was increased, while an increased ratio of B3+ to O2‐ or Si4+ to O‐ increased stability. The reducibility of Bi3+, Sb3+, and Pb2+ are not easily interpreted. Silver showed reduction at approximately 130°C., bismuth at 200°C., lead at 350°C., and antimony at 400°C.