isotopic splitting as well as the isotopic shifts. (The stable isotopes are $^{204}$Pb, $^{206}$Pb, $^{207}$Pb, and $^{208}$Pb.) We again assumed a solar isotope ratio for Pb though as with Rb, our tests confirmed that the derived elemental Pb abundance was not sensitive to this choice. For the solar Pb abundance, we adopted log $\epsilon$(Pb) = 1.95 from @grevesse98.

In the subsequent sections, we compare the globular cluster Pb abundances with those obtained in field stars with \[Fe/H\] $>-2.0$ by other investigators. However, we further restrict the comparison by avoiding stars with known $s$-process enhancements leaving only a handful of stars from two studies, @sneden98 and @travaglio01. Again we attempt to put the Pb abundance measurements onto a common scale. Our $gf$ value is identical to that used by @sneden98 so we do not adjust their Pb abundances. @travaglio01 used a different Pb line (3683 Å) and they did not list the adopted $gf$ value. Since there are no stars common to both analyses, we do not make an adjustment to their Pb abundances and caution that there may be a systematic offset.

Additional elements
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We also measured abundances for Al, Si, Y, Zr, La, and Eu in the M 