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We report the analysis of optical spectra of the extreme helium star LSS 3184(BX Cir) to determine its effective temperature and gravity throughout itspulsation cycle. The spectra were also used to measure its chemical abundances.  We report rest gravity, log g = 3.38 +/- 0.02, and a chemical abundancemixture consistent with those reported earlier in a study using an opticalspectrum with lower spectral resolution and a lower signal to noise ratio. Ouranalysis decreases the upper limit for the H abundance to H < 6.0 (massfraction < 7.1 x 10^-7). Our gravity corresponds to stellar mass M = 0.47 +/-0.03 M_sun.  We find that the effective log g varies through the pulsation cycle with anamplitude of 0.28 dex. The effective gravity is smaller than the rest gravityexcept when the star is very near its minimum radius. The change in effectivegravity is primarily caused by acceleration of the stellar surface.  Based on the optical spectra, we find the temperature varies with anamplitude of 3450 K. We find a time averaged mean temperature, 23390 +/- 90 K,consistent with that found in the earlier optical spectrum study. The meantemperature is 1750 K hotter than that found using combined ultraviolet spectraand V and R photometry and the variation amplitude is larger. This discrepancyis similar to that found for the extreme helium star V652 Her.Comment: 7 pages, 6 figures, LaTeX, to be published in A&

Temperature and gravity of the pulsating extreme helium star LSS 3184 (BX Cir) through its pulsation cycle