Frederick Thomas Trouton (; 24 November 1863 – 21 September 1922) was an Irish experimental physicist known for Trouton's rule and his experiments to detect the

Earth's rotation Earth's rotation or Earth's spin is the rotation of planet Earth around its own Rotation around a fixed axis, axis, as well as changes in the orientation (geometry), orientation of the rotation axis in space. Earth rotates eastward, in progra ...

through the

luminiferous aether Luminiferous aether or ether (''luminiferous'' meaning 'light-bearing') was the postulated Transmission medium, medium for the propagation of light. It was invoked to explain the ability of the apparently wave-based light to propagate through empt ...

Life and work

Trouton was born in

Dublin Dublin is the capital and largest city of Republic of Ireland, Ireland. Situated on Dublin Bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, and is bordered on the south by the Dublin Mountains, pa ...

on 24 November 1863, the youngest son of the wealthy and prominent Thomas Trouton. He attended Royal School Dungannon and went on to Trinity College, Dublin in 1884, where he studied engineering and physical science. While still an undergraduate student, Trouton observed a relationship between boiling points and energies of vaporisations, which he presented in two short papers. He found the change of entropy per mole for vaporisation at a boiling point is constant, or expressed mathematically ΔS_m,vap = 10.5 R (where R is the ideal gas constant). This became known as Trouton's rule and, despite having some exceptions, is used to estimate the

enthalpy Enthalpy () is the sum of a thermodynamic system's internal energy and the product of its pressure and volume. It is a state function in thermodynamics used in many measurements in chemical, biological, and physical systems at a constant extern ...

of vaporisation of liquids whose boiling points are known. Trouton himself belittled his discovery as it was merely the result of an afternoon's manipulation of data from a book of tables. Before graduating he also took a leading role in

surveying Surveying or land surveying is the technique, profession, art, and science of determining the land, terrestrial Plane (mathematics), two-dimensional or Three-dimensional space#In Euclidean geometry, three-dimensional positions of Point (geom ...

for a railway. Trouton graduated Master of Arts and

Doctor of Science A Doctor of Science (; most commonly abbreviated DSc or ScD) is a science doctorate awarded in a number of countries throughout the world. Africa Algeria and Morocco In Algeria, Morocco, Libya and Tunisia, all universities accredited by the s ...

in 1884, and was immediately appointed assistant to the professor of experimental physics, George Francis FitzGerald. They collaborated on many experiments and became good friends; FitzGerald's influence can be seen in much of Trouton's early work. Trouton was elected a

Fellow of the Royal Society Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the Fellows of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural science, natural knowledge, incl ...

in June 1897. His application citation read: "''Discovered the law connecting the latent heat of vaporisation and molecular weights of bodies known as "Trouton's law" and experimentally determined the directions of vibration of electric and inaquatic force in plane polarised light. He has made other important observations on the phase of secondary waves and on the influence of the size of the reflector in Hertz's equipment''." A 1902 appointment as Quain Professor of Physics at

University College London University College London (Trade name, branded as UCL) is a Public university, public research university in London, England. It is a Member institutions of the University of London, member institution of the Federal university, federal Uni ...

led to a 12-year career of experimental physics, including work on the Trouton-Rankine experiment. He received an OBE in 1918. Trouton married Anne Maria Fowler in 1887 and they had four sons and three daughters. Their first two sons, Eric and Desmond, were killed in

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

. He became severely ill in 1912 and an operation in 1914 left him paralysed in the lower limbs and caused his retirement. Despite this, he retained the wit and charm he was known for. After retiring, Trouton lived in Tilford, Surrey, and then Downe in Kent where he died on 21 September 1922.

References

{{DEFAULTSORT:Trouton, Frederick Thomas Irish physicists 1863 births 1922 deaths Alumni of Trinity College Dublin Scientists from Dublin (city) People educated at the Royal School Dungannon Fellows of the Royal Society Academics of University College London