Measured velocities of the chromospheric emission (*) and of the absorption components (﹩\diamond ﹩ and ﹩\square ﹩) for the M3IIIb star μ Gem (upper) and the M3.4III γ Cru (lower). The increase in the mean velocity of the wind absorption (as shown by the blue diamonds) with increasing line opacity reflects the acceleration of the wind with height. The chromospheric emission for γ Cru is slightly redshifted with a more rapidly accelerating wind than that of μ Gem.