Lord Kelvin. Portrait of Lord Kelvin (1824-1907) teaching a physics class in Glasgow. Born William Thomson, the Scottish physicist and mathematician entered Glasgow University at the age of ten and was later to be its professor of natural philosophy for 53 years. Kelvin supported Joule's thermodynamics work and later proposed a law of the conservation of energy. In 1848 Thomson proposed the existence of an absolute zero temperature and used it as a basis for measuring heat. Kelvin worked in electromagnetism, being the first to use vectors to represent magnetic induct- ion and magnetic force. He improved electric cable design, making trans-Atlantic telegraphy viable.