Hugh Longbourne Callendar

Hugh Longbourne Callendar FRS (18 April 1863 – 21 January 1930) was a British physicist known for his contributions to the areas of thermometry and thermodynamics.

Callendar was the first to design and build an accurate platinum resistance thermometer suitable for use, which allowed scientists and engineers to obtain consistent and accurate results. He conducted experiments and researched thermodynamics, producing and publishing reliable tables on the thermodynamic properties of steam used for calculations. Callendar worked with multiple institutions during World War I, helping to research and develop useful tools for the Navy.

Callendar received awards such as the James Watt Medal of the Institution of Civil Engineers (1898) and the Rumford Medal (1906). He was elected as a Fellow of the Royal Society, and later a member of the Physical Society of London. Callendar was also nominated for the Nobel Prize in Physics three times.

He died at home in Ealing, after an operation in 1930.