1. S. A. Friedberg, inTemperature Its Measurement and Control in Science and Industry(Reinhold Publishing Corporation, New York, 1955), Vol. 2, Chap. 20.
2. See Discussion by J. R. Clement, reference 1, p. 380.
3. The germanium resistor was kindly furnished by J. E. Kunzler of the Bell Telephone Laboratories.