the continuum placement strongly affects the derived Rb abundances from the 7947 Å line. Furthermore, unidentified blends, atmospheric absorption, and fringing are more prevalent in this spectral region. (CN lines lie in this region may be absent in these metal-poor globular cluster stars.)

In the subsequent sections, we compare our globular cluster Rb abundances with field and cluster stars with \[Fe/H\] $> -2.0$ analyzed by other investigators. We now attempt to place the various Rb abundance measurements onto a common scale. While the isotope ratio of Rb cannot be measured in Arcturus, the elemental abundance ratio is well known. Using the @arcturus Arcturus atlas, we measured an abundance \[Rb/H\] = $-$0.55 using a model atmosphere with [$T_{\rm eff}$]{}/$\log g$/$\xi_t$ = 4300/1.5/1.55 obtained using the spectroscopic criteria described in Section \[sec:param\]. The adopted Rb $gf$ value was identical to that used by @tomkin99 and our derived Rb abundance is in very good agreement with their measured value, \[Rb/H\] = $-$0.58. Since Arcturus is common to both studies and our derived abundances are essentially identical, we therefore make no adjustment to the @tomkin99 Rb abundances. @gratton94 use the same $gf$ value, though the relative strengths of the hyperfine components differ slightly. We 