Description: Colour mezzotint of Professor William Thomson, Lord Kelvin.

Caption: That year William's father was appointed professor of mathematics at the University of Glasgow and the family moved to Scotland. William studied in his father's classes and matriculated (became an official student) at the University at the age of 10! He became the Professor of Natural Philosophy at Glasgow at the age of 22 and was knighted in 1866 for his work on submarine telegraph cables.

Introduction: Professor William Thomson was the son of Professor James and Margaret Thomson, born on June 26, 1824, at the family home in East College Square, Belfast. His father was an Irish mathematician from Ballynahinch and his mother was the daughter of a Glasgow merchant. She died in 1830 when William was just six years of age.

Background: Lord Kelvin was the most highly honoured and influential scientist of his time. The first of the "Science Lords" he was elevated to the peerage by Queen Victoria in 1892 taking his title, 1st Baron Kelvin of Largs, from the river that runs below the present site of the University and the town of Largs in North Ayrshire where his house Netherhall still stands. His name was given to the absolute scale of temperature. He is buried next to Sir Isaac Newton in the nave of Westminster Abbey where a stained glass window was placed to Kelvin's memory in 1913.

Historical Context: Invention of the mezzotint engraving process - Who: Siegen, Ludwig von (circa 1609-1680) Dutch born German engraver

Historical Context: Invention of the mezzotint engraving process by Seigen - When: 1642 - Where: Hesse-Kassel, Hesse-Nasau, Germany

Historical Context: Painting of Kelvin in oils on canvas by Herkomer - When: circa 1892 - Where: Unknown, probably London, England

Historical Context: Painting of oils on canvas - Who: Sherkomer, Hubert von, Sir (1849-1914) German born British artist

Historical Context: Production of a mezzotint from a painting of Kelvin in oils on canvas by Herkomer - Who: Crawford, Thomas Hamilton (fl.1890-1930) Engraver

Historical Context: Production of mezzotint by Crawford - Where: Unknown, probably London, England

Historical Context: Production of the mezzotint by Crawford - When: circa 1895

Historical Context: Subject of the portrait - When: 1892 - Where: Unknown, probably London, England - Who: Professor William Thomson (1824-1907) Sir William Thomson from 1866 and Ist Baron Kelvin of Largs from 1892 better known as Lord Kelvin