Microfiche. Although It Is Recognized That Certain Portions Are Illegible, It Is Being Released in the Interest of Making Available as Much Information as Possible

We have performed IUB observations of interstellar zinc toward 10 stars. We find that zinc is at most only slightly depleted in the interstellar medium; its abundance may serve as a tracer of the true metallicity in the gas. The f local interstellar medium has abundances that apparently are homogeneous to t within a factor of two, when integrated over paths of about 500 pc, and this result is important for understanding the history of nucleosynthesis in the solar neighborhood. In an appendix we analyse the intrinsic errors in detecting weak interstellar lines and we suggest how this error limit may be lowered to 5 mi per target observation. Subject headings: interstellar: abundances ultraviolet: spectra