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The ultraviolet spectrum of the M-giant $\mu$ Gem (M3 IIIab) is sampled at selected important wavelengths with the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST). The wavelength regions are chosen to include lines sensitive to turbulence and flow velocities in the stellar chromosphere and wind acceleration region, as well as some fiducial photospheric absorption features. The dynamics of the outer atmosphere of $\mu$~Gem are examined using the observed profiles and positions of chromospheric emission lines of C~II, Fe~II, Mg~II, Fe~I, referenced to photospheric absorption lines of Fe~I. The content of the spectra and the inferred flow and turbulent velocities are compared to those found for the other cool, low-gravity stars observed with GHRS, including $\alpha$~Ori (M2~Iab) and $\gamma$~Cru (M3.4 III).
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