Lord Kelvin (1824-1907), born William Thomson, Scottish physicist and mathematician. Thomson was among the first to support Joule's work on the mechanical equivalent of heat". Together, in 1852, they discovered that when a gas is allowed to expand freely, its temperature drops slightly, an important phenomenon known as the Joule-Thomson effect. In 1848 Thomson proposed the existence of absolute zero and suggested the use of the absolute temperature scale, which was named the Kelvin scale. In 1866 he was knighted for his improvements to galvanometers & signal-carrying cables used on the newly-laid Atlantic cable. This portrait was published in Picture Magazine, 1894."