Dielectric constant of distilled water.---The dielectric constant of distilled water was measured with a vacuum tube source of voltage throughout a range of periods extending from about $T=1.31\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ second to $T=8.49\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ second corresponding to vacuum wave-lengths of 3.918 meters to 25.47 meters. The value obtained for the dielectric constant is $\ensuremath{\epsilon}=78.57$ at 25\ifmmode^\circ\else\textdegree\fi{}C and is independent of the period within the above range of periods.