Description
This instrument was manufactured in the workshop set up by the University of Cambridge’s first Professor of Mechanism and Applied Mechanics, James Stuart. (Stuart was effectively the University's first Professor of Engineering, but the University disliked that term, hence the rather convoluted job title). Lacking University support, Stuart funded his workshop by taking commissions to make instruments for colleagues in other scientific departments. Designed to measure small variations in electric current, this instrument, like Wh.1340, was made for the Cavendish Laboratory. Demand for instruments from Stuart’s workshop was so great that one of Stuart’s best technicians, Robert Fulcher, left in 1879 to set up in partnership with Albert Dew-Smith as a private business on Panton Street. After Fulcher left the partnership, this business would become the Cambridge Scientific Instrument Company in 1881.
07/08/2017
Created by: Josh Nall on 07/08/2017

Description
The Galvanometer

The galvanometer is one of the earliest electrical measuring instruments and was invented by Leopold Nobili (1784-1835). A galvanometer functions through the heating effect of a current (using either a wire or a thermocouple) and it is used to measure electrical currents. Measuring devices such as the galvanometer were important to scientists as they tried to understand electricity and eventually use it.

The galvanometer measures current, which is the quantity of charge moving past a certain point per unit of time. The galvanometer used magnetized needles and copper wire in the form of a coil to achieve this.

The galvanometer on display in the electrical case as shown opposite is a modified design by Andre Broca, who was the Professor of Physics at L'Ecole Polytechnique in Paris. Broca increased the strength of the magnetic poles at the center of the coil using a special arrangement.

Before the invention of the galvanometer the most sensitive indicator of electric current was freshly prepared frog's legs which would twitch when a current was applied to them.

In the 1840's there was a great demand for galvanometers due to a rapidly expanding electrical industry. Many developments in galvanometers were made and the galvanometer was reproduced by many instrument makers all over Europe. Charles Wheatstone had a version made by Watkins and Hill in 1845 so that he could conduct experiments on the velocity of electricity.