William Thomson, 1st Baron Kelvin OM, GCVO, PC, PRS, PRSE, (26 June 1824 – 17 December 1907) was an Irish-born British mathematical physicist and engineer.

At the University of Glasgow he does important work in the mathematical analysis of electricity and formulation of the first and second laws of thermodynamics, and does much to unify the emerging discipline of physics in its modern form.

He works closely with mathematics professor Hugh Blackburn in his work.

He also has a career as an electric telegraph engineer and inventor, which propels him into the public eye and ensures his wealth, fame and honor.

For his work on the transatlantic telegraph project he is knighted by Queen Victoria, becoming Sir William Thomson.

He has extensive maritime interests and is most noted for his work on the mariner's compass, which had previously been limited in reliability.

Lord Kelvin is widely known for realizing that there is a lower limit to temperature, absolute zero; absolute temperatures are stated in units of kelvin in his honor.

On his ennoblement in 1892 in honor of his achievements in thermodynamics, and of his opposition to Irish Home Rule,he adops the title Baron Kelvin of Largs and is therefore often described as Lord Kelvin.

He is the first UK scientist to be elevated to the House of Lords.

The title refers to the River Kelvin, which flows close by his laboratory at the University of Glasgow.

His home is the imposing red sandstone mansion Netherhall, in Largs on the Firth of Clyde.

Despite offers of elevated posts from several world renowned universities Lord Kelvin refuses to leave Glasgow, remaining Professor of Natural Philosophy for over 50 years, until his eventual retirement from that post.

The Hunterian Museum at the University of Glasgow has a permanent exhibition on the work of Lord Kelvin, including many of his original papers, instruments and other artifacts.