A description is presented of the equipment for the measurement of the pulse size from Geiger‐Mueller counters, and the results are given for the gas mixtures 90 percent He 10 percent H2, 90 percent Ne 10 percent H2, 90 percent A 10 percent H2, 100 percent H2, and 90 percent A 10 percent O2for pressures from 2 to 30 cm of mercury, and for a mixture of 9.7 cm of argon and 1.2 cm of ethyl alcohol.