The internal friction of Li-Na, Li-K, Li-Cs, Li-Ag, Na-Cs, and Na-Ag metaphosphate glasses was measured at 0.5 Hz and 2 kHz. The dielec. losses were also measured from 40 to 160 Deg, at frequencies of 300, 3000, and 30,000 Hz. The ds. of the glasses were detd. and the molar vol. of O was calcd. In general, the mixed alkali behavior of metaphosphate glasses is very similar to the mixed alkali behavior of silicate glasses. Ag behaves in this respect like an alkali ion with approx. the same size as Na+.