History of the electrical units and early standards

In 1861 the British Association set up a committee, led by Thomson (i.e. Kelvin) and Clerk Maxwell, which proposed the electrical units which are still in use, based on the metric system. Names were given to them to avoid ambiguities, and prefixes based on ratios of 1000 were introduced, both on the lines suggested by Bright and Latimer Clark. These units, specified by material standards, became the International Units of 1893, which were in use until the SI units superseded them in 1948. The BA owned standard resistors made in 1865 and standard capacitors made in 1889. The resistors, which still exist, were less stable than the BA had hoped, and the true value of the BA ohm was uncertain.