Abstract :
THE PLATINUM resistance thermometer is the accepted interpolating device for the 1948 International Temperature Scale from −182.97 degrees centigrade to +630.5 degrees centigrade. When properly made, the reproducibility of its resistance justifies its calibration and use for measurements to 0.01 degree centigrade, or 1/80,000th of its temperature range. E. F. Mueller attacked this difficult resistance measurement problem with a hand-operated multiple-decade bridge.1 D. R. Stull attacked the problem with a mechanically balanced recorder using a slide-wire plus decades,2 and used the recorder for the determination of chemical purity by freezing point measurement. While Stull was building his recorder, the author and his associates also were building a recorder (using one of the several methods of electronic balancing which had then been developed). Based on the experience with these two types of recorders there was developed a third type, with improved precision, the experimental form of which is the subject of this article.
