Abstract
Assuming the same turbulent diffusion processes to be acting on both ordinary and tritiated water vapour, the evaporation rate of ordinary water can be computed from Ostlund's tritum measurements in hurricane Betsy. The hurricane evaporation rates, in the range of one to five cm per day, are subject to large uncertainties but are of the same order as found by Malkus and Riehl. The higher rates occur on a day when the hurricane is more intense, the lower rates when less vigorous.