Abstract :
Progress in the application of results in the domain of physics has been so rapid of late that there is a temptation to make the general statement that the pure physics of one quarter century becomes the engineering of the next. This, of course, would not be true in all domains of physics, but it is more or less valid in those with which the electrical engineer is most closely connected. The mounting number of uses for devices and phenomena discovered some years ago, for example the vacuum tube, photo-electricity, and the piezoelectric vibrations of crystals, is an apt illustration of the transfer from abstract interest to practical utility. It is, then, quite to the point for the electrical engineer, in forecasting and preparing for the developments of the future, to look to the electrophysics of the present day.