William Thomson (1824-1907), British physicist and mathematician, better known as Lord Kelvin. He did important work in the mathematical analysis of electricity and supported Joule's work in thermodynamics. He devised the absolute temperature scale known as the Kelvin scale, thus putting the second law of thermodynamics on a sound theoretical basis. In 1866 he was knighted for his work on Atlantic telegraph cable signals and galvanometers and raised to the peerage as Baron Kelvin in 1892. Kelvin worked in electromagnetism, being the first to use vectors to represent magnetic induction and magnetic force. He had extensive maritime interests, improving the reliability of the mariners' compass, inventing a tide machine and depth-measuring equipment. He was president of the Royal Society and also president of the Institute of Electrical Engineers.