1. S. Chapman and T. G. Cowling,The Mathematical Theory of Non-Uniform Gases(Cambridge University Press, New York, 1939).
2. Because of an unfortunate error in the author’s 1939 review paper the photoelectric work function was said to be given by (Q1∕2+Jgr;). It is evident from Fig. 1 that the correct value is (Q1+Jgr;).