New $X\ensuremath{-}\mathrm{Ray}$ Line ${\ensuremath{\gamma}}_{6}$ for Elements Tantalum to Uranium.\char22{}The two emission lines ${\ensuremath{\gamma}}_{2}$ and ${\ensuremath{\gamma}}_{4}$ are found to be in reality three lines. The new line ${\ensuremath{\gamma}}_{6}$ has wave-lengths of 1110, 1072, 842, 630 and 593 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}11}$ cm. for Ta, W, Tl, Th and U respectively. In the cases of Ir, Pt and Au it is too near ${\ensuremath{\gamma}}_{2}$ and in the cases of Pb and Bi too near ${\ensuremath{\gamma}}_{3}$ to be separated.