In the study of ionization chambers filled with highpressure gases, the recombination of ions may be neglected if the study is carried out at ionization levels close to the cosmic-ray background. For engineering reasons, it is desirable to determine the volt--ampere characteristics of the chambers within a wide ionization density range. Four series of measurements were carried out at various ionization densities, varying the distance between the electrodes from 0.3 to 2.7 cm by means of Teflon sleeves. The ionization currents were measured by means of a compensationtype electrometric instrument with an error of plus or minus 1%; a dry cell battery, the tension of which could be varied from 0 to 4500 v, served as the high-voltage source. The results of measurements carried out using a distance of 0.9 cm between the electrodes confirmed that for a constant gas pressure, the relationship I = F(E) remains identical regardless of the ionization density, indicating the absence of volume recombination; in some cases initial recombination was observed. The voltage selected determines the current losses due to initial recombination of the ions and indicates the increase in the size of the chamber required for obtaining the needed sensitivity. The chambers were filledmore » with N/sub 2/ containing less than 0.01% CO/sub 2/ and 0.4% O/sub 2/.« less