The Hydrogen Atom with a Spinning Electron in Wave Mechanics.

of all substances, great fields of equilibria hitherto unsuspected, in which the individual states differ from one another with respect to the new variable, the number of photons. If such a necessity arises and the law of conservation of photons can be established, it may be necessary to revise still further our ideas of thermal radiation, for in that case it would be doubtful whether what is known as black body radiation is as definite a thing as has been supposed. 1 Lewis, these PROCZEDINGS, 13, 307 (1927). 2 Lewis, Nature, 118, 874 (1926). 8 Einstein, Ann. Physik, 38, 881 (1921); J. Physique, 3, 277 (1913).