Elemental abundances of field horizontal branch stars -- IV. HD 74721, 86986 and 93329

Studies of 200-Å-long regions recently obtained with a 3000-pixel-long CCD at the coudé feed telescope of the Kitt Peak National Observatory (KPNO) are used to extend fine analyses of the field horizontal branch A stars HD 74721, 86986 and 93329. Spectra of other stars obtained both at KPNO and at the Dominion Astrophysical Observatory show that previously found wavelength-dependent equivalent width systematics are probably due to how the spectra were measured as well as to resolution differences. The derived He/H ratios agree with the Buzzoni et al. value of 0.075, within measurement errors. Some derived elemental abundances are found to be correlated with one another.