Three independent measurements of the work function of uranium have been reported. The values obtained were were made with uranium wire and since, as shown by the authors, uranium is very readily oxidized at pressures of 10/sup -7/ mm Hg to give a relatively non-volatile oxide, one surmises that some of these determinations were subject to error because of vacuum conditions. Attempting to investigate the validity of this criticism, the authors have measured the thermionic properties of a uranium wire in such a manner that some information regarding the cleanliness of the surface can be deduced. The two types of measuremente accomplished were the change in the thermionic constants of the Richardson equation with time of heating in hydrogen, and the dependence of current on the retarding potential. (auth)

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