Evershed & Vignoles Conductivity Meter

Evershed & Vignoles Conductivity Meter

Evershed & Vignoles

1907

Method: Electrical resistivity

Description

This version of Evershed’s Conductivity Meter was developed in 1907 in London. It was the first meter by Evershed & Vignoles to use the same coil for electricity generation and measurement, eliminating a number of errors previously produced by the interaction of the magnetic fields of two coils. Titled a “megger”, or “ohmmeter”, it measures the resistance of an ionic solution, but displays its reciprocal – the conductivity.