Abstract
Accurate values of electron drift-velocity in purified noble gases and nitrogen have been obtained by measuring the transit time of photoelectrons across the gap of a parallel-plate condenser. Drift velocities in pure krypton and xenon have not been measured before. The values obtained for the other gases are invariably lower than those reported by Nielsen, the discrepancy for neon being large. The sharp maximum found by English and Hanna for argon at Ep0<0.1 and tentatively ascribed by them to the Ramsauer effect was not observed in the purified gas.