Balloon--borne measurments of the small ion concentration were made using a Gerdien condenser. The insturument differs from others in that a lobe pump was used to draw air through the ion collector thus insuring a well-known and constant flow rate. The profiles were found to be quite repeatable over a two-year period (1977--1979). In contrast to previous data the new profiles are much smoother and show only a small decline in concentration above the ion density maximum. It is believed that this discrepancy can be attributed to a poorly known and variable flow rate in the older instruments.