  We present a new measurement of atmospheric muons made during an ascent of
the High Energy Antimatter Telescope balloon experiment. The muon charge ratio
mu+/mu- as a function of atmospheric depth in the momentum interval 0.3-0.9
GeV/c is presented. The differential mu- intensities in the 0.3-50 GeV/c range
and for atmospheric depths between 4-960 g/cm^2 are also presented. We compare
these results with other measurements and model predictions. We find that our
charge ratio is ~1.1 for all atmospheric depths and is consistent, within
errors, with other measurements and the model predictions. We find that our
measured mu- intensities are also consistent with other measurements, and with
the model predictions, except at shallow atmospheric depths.
