Daily Variation of Water and Dry Matter in the Leaves of Corn and the Sorghums.

Filaments 1 and 2 were coated with BaO 50%0, SrO 25%, CaO 25%, Filaments 3 and 4 with BaO 50%0, SrO 50%, and Filaments 5 and 6 with CaO alone. It appears that for Wehnelt cathodes the values 0 and bR/e show a good correspondence. This is a strong point in favor of the view that the emission of electrons from Wehnelt cathodes is due to a similar mechanism to that causing the emission from heated pure metals. It is also a further proof of the substantial correctness of Richardson's hypotheses to account for the emission of electrons by hot bodies.