Joseph Black (16 April 1728 – 6 December 1799[1]) was a Scottish physician, known for his discoveries of latent heat, specific heat, and carbon dioxide. He was professor of Medicine at University of Glasgow (where he also served as lecturer in Chemistry). James Watt, who was appointed as philosophical instrument maker at the same university (1756), became involved in Black's works and conducted experiments on steam with Black. The chemistry buildings at both the University of Edinburgh and the University of Glasgow are named after Black. In about 1750, Joseph Black developed the analytical balance based on a light-weight beam balanced on a wedge-shaped fulcrum. Each arm carried a pan on which the sample or standard weights was placed. It far exceeded the accuracy of any other balance of the time and became an important scientific instrument in most chemistry laboratories.[2]. In 1757, he was appointed Regius Professor of the Practice of Medicine at the University of Glasgow. In 1761 Black deduced that the application of heat to ice does not cause its immediate liquefaction, rather the ice absorbed the heat without a rise in temperature.[3] Additionally, Black observed that the application of heat to boiling water does not result in immediate evaporation. From these observations, he concluded that the heat applied must have combined with the ice particles and boiling water and become latent. The theory of latent heat marks the beginning of thermal science.[4] Black's theory of latent heat was one of his more-important scientific contributions, and one on which his scientific fame chiefly rests. He also showed that different substances have different specific heats. This all proved important not only in the development of abstract science but in the development of the steam engine.[5]