SUMMARY OF DELTA-S METALLICITY MEASUREMENTS FOR BRIGHT RR LYRAE VARIABLES OBSERVED AT LICK OBSERVATORY AND KPNO BETWEEN 1972 AND 1987

From 1972 to 1987 we conducted a survey of the metallicity of faint RR Lyrae variables in the Galactic halo, using the ''Butler system'' of DELTAS. As part of the calibration of this program, we made approximat ely 500 observations of bright RR Lyraes as abundance standards. We su mmarize all the observations of these bright field RR Lyraes and provi de averaged values for the metallicity parameter DELTAS in Tables 3 an d 5. These averages represent the most precise definition of the Butle r system for the measurement of RR Lyme metallicities. The typical mea n error is 0.3 units in DELTAS, which corresponds to 0.05 dex in [Fe/H ]. We also briefly discuss the weaknesses in the determination of [Fe/ H] from DELTAS.