Measurements of ionospheric electric fields in the auroral and polar cap regions by means of balloon-borne sensors are described. Launches took place from the Norwegian station of Andenes (And¿ya) (69¿N, 16¿E) during summer 1974. The Balloons drifted over the Atlantic to the west coast of Greenland nearly along 69.5¿N geographic latitude (within ¿1.5¿) and were followed by telemetry stations at Andenes, Raufarh¿fn (Iceland), and S¿ndre Str¿mfjord (Greenland). The electric field data are discussed from the point of view of the two-cell magnetospheric convection pattern which has been established in recent years. Of particular interest are the well-recognized features of the Harang discontinuity as well as electric field data in the vicinity of the polar cusp region.