A large modified polar nephelometer was constructed for the purpose of making high altitude atmospheric optics measurements. The instrument is balloon-borne and measures the angular volume scattering function from ground to better than 26 km in absolute quantities. The results of the initial flight with the unit are presented and they depict the variability in this parameter over the altitude profile for three scattering angles and four wavelengths. In addition, the polarization and the forward-to-backscatter ratio of the scattered light are shown to be sensitive indicators of the atmosphere's vertical aerosol structure. The import of these preliminary results is, however, in pointing out the capabilities of this instrument, which can provide quantitative information on fundamental optical parameters of the atmosphere without the constraints inherent in other techniques.