A millisecond chronoscope

This paper opens with a discussion of various methods of measuring short time intervals and then proceeds to describe a condenser chronoscope suitable for the measurement of intervals initiated and terminated by momentary or sustained makes or breaks in electrical circuits. The range is from 2 millisec to 1 000 millisec. The voltage on the condenser is measured by a simple valve voltmeter which is used only as a transfer iastrument, the final reading being given on three decade dials of a potentiometer. This reading is converted into milliseconds by the use of specially prepared tables. The instrument is self-contained and transportable, power being obtained from dry batteries. The accuracy, which is limited chiefly by dielectric absorption in the condenser and by leakage in the components, is of the order of 0.5 millisec on short intervals or 0.5% on long intervals.