THE SUPERCONDUCTING TRANSITION TEMPERATURE OF LEAD

Abstract
The temperature of the superconducting transition has been measured for high purity lead samples from three different sources. The transition temperature for all samples agreed to within 0.001° and was determined with a gas thermometer to be 7.193° K ± 0.005°. The transition width for all samples was roughly 0.004°. Some comments on the use of carbon radio resistors as thermometers in the temperature range 3° to 30° K are included.