Empirical analysis of complex electric waves

N. E. Bonn: The last method described in Mr. Horton´s paper and the one which he evidently prefers, involves the use of a sine-wave oscillator of variable frequency. Now a sine-wave oscillator, especially one whose frequency may be varied over a large range without disturbing the wave form, would make a very valuable adjunct to many a laboratory. Will Mr. Horton please state what method he uses to make certain of the purity of the wave form?