Signedunsigned
Inscribedon circular paper on top: POTENTIOMETER / No. 2. / CRUFT LABORATORY
FunctionFor making highly accurate and precise general electrical measurements such as potential difference and current, also for measuring temperature and pH.
A potentiometer is an instrument for measuring the potential (voltage) in a circuit against a standard cell. Before the introduction of the moving coil and digital volt meters, potentiometers were used in measuring voltage, hence the '-meter' part of their name. The method was described by Johann Christian Poggendorff around 1841 and became a standard laboratory measuring technique.
This information, and more, can be found on the following website.
ProvenanceFrom the Department of Physics, Cruft Laboratory, Harvard University.