4 - Units and Standards

Summary

An agreed system of electrical units and standards was crucial to building a workable cable systemin the 1860s, as well as to advancing electrical science. Without such standards, it was almost impossible to extend accurate electrical knowledge beyond a single laboratory or testing room. Amid conflicts over competing standards and in response to rising demands from the telegraph industry, in 1861 William Thomson called on the British Association for the Advancement of Science to establish a Committee on Electrical Standards. The committee proved very influential, and its work marks one of the most important points of intersection between electrical science and technology in the mid-nineteenth century. Led by James Clerk Maxwell ,and Fleeming Jenkin, the committee determined the value of the ohm experimentally in 1862–64 and distributed standard resistance coils around the world. Standard ohms soon became a key part of quality control in the cable industry; indeed, the aim in manufacture became to make a cable that was, in effect, a chain of standard ohms strung end to end, its properties at each point known and recorded.