Observations of Mars previously reported in 10 narrow bands between 3150 A and 1.06 /x and in UBV are analyzed for brightness variations which correlate with longitude of the central meridian. Such an effect is found for A ^ 5000 A, with some evidence for such a correlation at A = 4570 A. The data are then corrected to the mean (over longitude) brightness and a linear phase curve fitted to those observations with phase angle /^15°. An opposition effect (anomalous brightening at small phase

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... s) is found for wavelengths A ^5500 A, in contrast to a result previously reported. The magnitude at zero phase, phase coefficient, and monochromatic albedo are computed for Mars as a function of wavelength.