"I well remember how, on the publication of his early and important paper on ionisation in stellar atmosphere, the late Professor Alfred Fowler drew my attention to it and emphasized its fundamental importance. And so it proved, for this paper was the stimulus  to the work of Milne, R.H.Fowler, and others in subsequent years. In fact, almost all work on stellar atmosphere has been based on it, either directly or indirectly. The paper provided a new method of attack and opened the way to the solution of many problems that had been puzzling."

Sir Harold Spencer-Jones, F.R.S