Intercomparison of platinum resistance thermometers between -190 degrees and 445 degrees C

Eight platinum resistance thermometers satisfying the requirements of the International Temperature Scale were calibrated on the International scale and intercompared from -190 to 445 C. The o's of the Callendar-Van Dusen equations for seven of these thermometers ranged from 1.49375 to 1.49862. The {) for the eighth'jthermometer,IE, was 1.51155. After minimizing the effects of relative calibration errors, the maximum difference between the readin~s of the group of seven thermometers was 7 millidegrees between -190 and 0 C and 1.3 millidegrees between 0 and 100 C. Maximum differences from the mean were 4.0 and 0'8 millidegree, respectively. For thermometer E, deviations from the mean of the other seven were 15 millidegrees at -110 C and 3 millidegrees at + 50 C. Tables of differences between readings of platinum resistan ce thermometers arising from assumed calibration errors at the fixed points were calculated and are included.