The Theory of Radiation

Abstract

IN his letter published in NATURE of October 9, Prof. Maclaren has referred to my use of the concept of a natural unit of angular momentum, and perhaps a few explanatory remarks may be useful, as the work has not been published in a journal devoted to physics. The concept first appeared in my paper on the constitution of the solar corona, published in the Monthly Notices of the Royal Astronomical Society in June of last year. It was found that the energy frequency ratios of the atomic systems, which were held to be the origin of the main lines in the coronal spectrum, were always simple multiples of the quantity h/2π, where h is Planck's constant. As these ratios were nothing more or less than the angular momenta of the atoms, the conclusion was forced upon me that Planck's h could only be an angular momentum.