The low energy (0.15-3 keV) proportional counter detectors of the A-2 experiment on the x-ray astronomy satellite HEAO-1 have detected nighttime atmospheric emissions at the limb of the earth. Three observations of this phenomenon occurred during the first two months of operation. On two occasions, fluxes greater than the diffuse galactic background were detected when the detectors scanned the limb in the vicinity of the magnetic conjugate point of the South Atlantic Anomaly. Enhanced emissions were also observed on a single scan of the atmosphere over northern Africa. The x-rays were presumed to result from bremsstrahlung generated by precipitating electrons. In the case of the emissions related to the Anomaly conjugate point, it is suggested that the electrons were secondaries backscattered from the atmosphere above the Anomaly during the intensified precipitation of radiation belt particles that occurs throughout a magnetic storm recovery period. These initial observations demonstrate that the earth's atmosphere can be a significant x-ray source at low latitudes as well as in the auroral zones, and hence that it may be practical to remotely monitor the global morphology of particle precipitation by satellite observations of terrestrial x-rays.