  We have searched the far-UV spectra of five clusters of galaxies observed
with the Hopkins Ultraviolet Telescope (HUT) for emission in the resonance
lines of O VI (1032,1038 A) and C IV (1548,1551 A). We do not detect
significant emission from either species in any of the spectra. Lieu et al.
[ApJ, 458, L5 (1996)] have recently proposed a warm [(5-10) * 10^5 K] component
to the intracluster medium (ICM) to explain the excess 0.065-0.245 keV flux
present in EUVE and ROSAT observations of the Virgo cluster. If the surface
brightness of this warm component follows that of the hot, x-ray-emitting gas
(i.e., is centrally condensed), then our upper limit to the O VI surface
brightness in M87 is inconsistent with the presence of substantial 500,000 K
gas in the center of the Virgo cluster. This inconsistency may be alleviated if
the central gas temperature is >= 750,000 K. HUT limits on the O VI surface
brightness of the four other clusters can provide important constraints on
models of their ICM.
