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 plates for two different plate distances. Plate was covered with a thin layer of powdered metallic uranium; plate, connected with the electrometer, was provided with a guard-ring.

Fig. 2 shows that the intensity of the current becomes constant for high potential differences between the plates. Fig. 3 represents the same curves on another scale, and

comprehends only relative results for small differences of potential. At the origin, the curve is rectilinear; the ratio of the intensity of the current to the difference of