Robert John Strutt, 4th Baron Rayleigh
Encyclopedia
Robert John Strutt, 4th Baron Rayleigh (28 August 1875 – 13 December 1947) was a British
peer
and physicist. He discovered "active nitrogen", was the first to distinguish the glow of the night sky.
He was born at Terling Place, the family home near Witham, Essex, the eldest son of John William Strutt, 3rd Baron Rayleigh and his wife Evelyn Georgiana Mary (née Balfour). He was thus a nephew of Arthur Balfour
and of Eleanor Mildred Sidgwick
. He was educated at Eton College
and Trinity College, Cambridge
, where he initially read mathematics, but changed after two terms to Natural Sciences. He became a research student in physics at the Cavendish Laboratory
under J. J. Thomson
, whose biography he subsequently wrote. His work at this time was on discharge of electricity through gases, including early work on x-rays and electrons. He wrote one of the first books on radioactivity, The Becquerel rays and the properties of radium(E. Arnold, 1904). He was awarded the Coutts Trotter studentship in 1898 and was a Fellow of Trinity College 1900-1906.
Strutt was elected a Fellow of the Royal Society in May, 1905 when his candidature citation read: "Fellow of Trinity College, Cambridge. As one who has made discoveries in Physics and as the author of the following papers: - 'On the Least Potential Difference required to Produce Discharge through Various Gases' (Phil Trans, vol cxciii, 1893); 'The Dispersion of the Cathode Rays by Magnetic Gases' (Phil Mag,, Nov, 1899); 'The Discharge of Electricity through Argon and helium' (ibid, March, 1900); 'The Behaviour of Becquerel and Rontgen Rays in a Magnetic Field' (Proc Roy Soc, vol lxvi); 'The Conductivity of Gases under Becquerel Rays' (Phil Trans, vol cxcvi, 1901); 'The Tendency of the Atomic Weights to Approximate to Whole Numbers' (Phil Mag,, March, 1901); 'The Discharge of Positive Electrification by Hot Metals' (ibid, July, 1902); 'Electrical Conductivity of Metals and their Vapours' (ibid, Nov, 1902); 'Some Recent Investigations on Electrical Conduction' (Proc Roy Inst, April, 1903); 'Preparation and Properties of an Intensely Radio-active Gas from Metallic Mercury' (Phil Mag, July, 1903); 'Radio-activity of Ordinary Materials' (ibid, June, 1903); 'Absorption of Light by Mercury and its Vapour' (ibid, July, 1903); 'The Intensely Penetrating Rays of radium' (Proc Roy Soc, lxxii); 'Fluorescence of Crystals under Rontgen Rays' (Phil Mag, Aug, 1903); 'An Experiment to Exhibit the Loss of Negative Electricity by Radium' (ibid, Nov, 1903).. He delivered their Bakerian Lecture
in 1911 and 1919.
Strutt's best known work in the period 1904-1910 was the estimation of the age of minerals and rocks by measurement of their radium and helium content. In 1908 he was appointed Professor of Physics at Imperial College, London where he followed up his father's work on light scattering, which is now known as Rayleigh scattering
, resulting in some papers published in the Proceedings of the Royal Society. He published a biography of his father, the third Baron Rayleigh, with the title of "Life of John William Strutt, third Baron Rayleigh". Photographs of Robert John Strutt when he was young can be found in this book. Both the father and son's work on light scattering was discussed by Young in 1982. A sketch of Robert John Strutt when he was old can also be found in Young (1982). (Please see reference.)
In 1910 Robert Strutt discovered that an electrical discharge in nitrogen gas produced "active nitrogen", an allotrope considered to be monatomic. The "whirling cloud of brilliant yellow light" produced by his apparatus reacted with quicksilver to produce explosive mercury nitride.
In 1916, working with his colleague Alfred Fowler
, Strutt was the first to prove the existence of ozone in the atmosphere by examining the ultra-violet spectrum of the setting sun. Strutt proved that the ozone was mainly located in the upper atmosphere, in what is now called the ozone layer
Strutt inherited his title on the death of his father in 1919, becoming the 4th Baron Rayleigh. He resigned his chair at Imperial College but continued to experiment at home in the private laboratory that his father had established in an old stable block. His earlier work on gaseous discharge and fluorescence, led to further work on the luminosity of the night sky. He was the first to differentiate between two types of light from the night sky, the aurora
or "northern lights", and the airglow that prevents the sky ever being completely dark anywhere on earth. In 1929 he was the first to measure the intensity of the light from the night sky. This work led to his posthumous nickname "the Airglow Rayleigh". The importance of his unpublished data was such that the US Airforce Cambridge Research Laboratories acquired it in 1963, acquiring almost by accident at the same time many of his father's experimental notebooks. They are now housed in the Mcdermott Library of the U.S. Air Force Academy, Colorado Springs, Colorado.
He died in Terling, Essex. He had married twice: firstly on 5 July 1905 Lady Mary Hilda Clements, daughter of Robert Clements 4th Earl of Leitrim (she died 1919) and secondly, in 1920, Kathleen Alice, daughter of John Coppin-Straker of Northumberland. He had five children by his first wife, including his heir John Arthur Strutt and the Hon Charlles Strutt; he had a further child by his second wife.
The rayleigh
, a unit of photon
flux
used to measure air glow, is named after him.
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
peer
Peerage
The Peerage is a legal system of largely hereditary titles in the United Kingdom, which constitute the ranks of British nobility and is part of the British honours system...
and physicist. He discovered "active nitrogen", was the first to distinguish the glow of the night sky.
He was born at Terling Place, the family home near Witham, Essex, the eldest son of John William Strutt, 3rd Baron Rayleigh and his wife Evelyn Georgiana Mary (née Balfour). He was thus a nephew of Arthur Balfour
Arthur Balfour
Arthur James Balfour, 1st Earl of Balfour, KG, OM, PC, DL was a British Conservative politician and statesman...
and of Eleanor Mildred Sidgwick
Eleanor Mildred Sidgwick
Eleanor Mildred Sidgwick, née Balfour was an activist for the higher education of women, Principal of Newnham College and a leading figure in the Society for Psychical Research.-Biography:...
. He was educated at Eton College
Eton College
Eton College, often referred to simply as Eton, is a British independent school for boys aged 13 to 18. It was founded in 1440 by King Henry VI as "The King's College of Our Lady of Eton besides Wyndsor"....
and Trinity College, Cambridge
Trinity College, Cambridge
Trinity College is a constituent college of the University of Cambridge. Trinity has more members than any other college in Cambridge or Oxford, with around 700 undergraduates, 430 graduates, and over 170 Fellows...
, where he initially read mathematics, but changed after two terms to Natural Sciences. He became a research student in physics at the Cavendish Laboratory
Cavendish Laboratory
The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the university's School of Physical Sciences. It was opened in 1874 as a teaching laboratory....
under J. J. Thomson
J. J. Thomson
Sir Joseph John "J. J." Thomson, OM, FRS was a British physicist and Nobel laureate. He is credited for the discovery of the electron and of isotopes, and the invention of the mass spectrometer...
, whose biography he subsequently wrote. His work at this time was on discharge of electricity through gases, including early work on x-rays and electrons. He wrote one of the first books on radioactivity, The Becquerel rays and the properties of radium(E. Arnold, 1904). He was awarded the Coutts Trotter studentship in 1898 and was a Fellow of Trinity College 1900-1906.
Strutt was elected a Fellow of the Royal Society in May, 1905 when his candidature citation read: "Fellow of Trinity College, Cambridge. As one who has made discoveries in Physics and as the author of the following papers: - 'On the Least Potential Difference required to Produce Discharge through Various Gases' (Phil Trans, vol cxciii, 1893); 'The Dispersion of the Cathode Rays by Magnetic Gases' (Phil Mag,, Nov, 1899); 'The Discharge of Electricity through Argon and helium' (ibid, March, 1900); 'The Behaviour of Becquerel and Rontgen Rays in a Magnetic Field' (Proc Roy Soc, vol lxvi); 'The Conductivity of Gases under Becquerel Rays' (Phil Trans, vol cxcvi, 1901); 'The Tendency of the Atomic Weights to Approximate to Whole Numbers' (Phil Mag,, March, 1901); 'The Discharge of Positive Electrification by Hot Metals' (ibid, July, 1902); 'Electrical Conductivity of Metals and their Vapours' (ibid, Nov, 1902); 'Some Recent Investigations on Electrical Conduction' (Proc Roy Inst, April, 1903); 'Preparation and Properties of an Intensely Radio-active Gas from Metallic Mercury' (Phil Mag, July, 1903); 'Radio-activity of Ordinary Materials' (ibid, June, 1903); 'Absorption of Light by Mercury and its Vapour' (ibid, July, 1903); 'The Intensely Penetrating Rays of radium' (Proc Roy Soc, lxxii); 'Fluorescence of Crystals under Rontgen Rays' (Phil Mag, Aug, 1903); 'An Experiment to Exhibit the Loss of Negative Electricity by Radium' (ibid, Nov, 1903).. He delivered their Bakerian Lecture
Bakerian Lecture
The Bakerian Lecture is a prize lecture of the Royal Society, a lecture on physical sciences.In 1775 Henry Baker left £100 for a spoken lecture by a Fellow on such part of natural history or experimental philosophy as the Society shall determine....
in 1911 and 1919.
Strutt's best known work in the period 1904-1910 was the estimation of the age of minerals and rocks by measurement of their radium and helium content. In 1908 he was appointed Professor of Physics at Imperial College, London where he followed up his father's work on light scattering, which is now known as Rayleigh scattering
Rayleigh scattering
Rayleigh scattering, named after the British physicist Lord Rayleigh, is the elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the light. The particles may be individual atoms or molecules. It can occur when light travels through...
, resulting in some papers published in the Proceedings of the Royal Society. He published a biography of his father, the third Baron Rayleigh, with the title of "Life of John William Strutt, third Baron Rayleigh". Photographs of Robert John Strutt when he was young can be found in this book. Both the father and son's work on light scattering was discussed by Young in 1982. A sketch of Robert John Strutt when he was old can also be found in Young (1982). (Please see reference.)
In 1910 Robert Strutt discovered that an electrical discharge in nitrogen gas produced "active nitrogen", an allotrope considered to be monatomic. The "whirling cloud of brilliant yellow light" produced by his apparatus reacted with quicksilver to produce explosive mercury nitride.
In 1916, working with his colleague Alfred Fowler
Alfred Fowler
Alfred Fowler, FRS was an English astronomer. Not to be confused with American astrophysicist William Alfred Fowler....
, Strutt was the first to prove the existence of ozone in the atmosphere by examining the ultra-violet spectrum of the setting sun. Strutt proved that the ozone was mainly located in the upper atmosphere, in what is now called the ozone layer
Ozone layer
The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone . This layer absorbs 97–99% of the Sun's high frequency ultraviolet light, which is potentially damaging to the life forms on Earth...
Strutt inherited his title on the death of his father in 1919, becoming the 4th Baron Rayleigh. He resigned his chair at Imperial College but continued to experiment at home in the private laboratory that his father had established in an old stable block. His earlier work on gaseous discharge and fluorescence, led to further work on the luminosity of the night sky. He was the first to differentiate between two types of light from the night sky, the aurora
Aurora (astronomy)
An aurora is a natural light display in the sky particularly in the high latitude regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere...
or "northern lights", and the airglow that prevents the sky ever being completely dark anywhere on earth. In 1929 he was the first to measure the intensity of the light from the night sky. This work led to his posthumous nickname "the Airglow Rayleigh". The importance of his unpublished data was such that the US Airforce Cambridge Research Laboratories acquired it in 1963, acquiring almost by accident at the same time many of his father's experimental notebooks. They are now housed in the Mcdermott Library of the U.S. Air Force Academy, Colorado Springs, Colorado.
He died in Terling, Essex. He had married twice: firstly on 5 July 1905 Lady Mary Hilda Clements, daughter of Robert Clements 4th Earl of Leitrim (she died 1919) and secondly, in 1920, Kathleen Alice, daughter of John Coppin-Straker of Northumberland. He had five children by his first wife, including his heir John Arthur Strutt and the Hon Charlles Strutt; he had a further child by his second wife.
The rayleigh
Rayleigh (unit)
The rayleigh is a unit of photon flux, used to measure air glow . It was first proposed in 1956 by D. M. Hunten, Franklin E. Roach, and J. W. Chamberlain. It is named for Robert John Strutt, 4th Baron Rayleigh . Its symbol is R...
, a unit of photon
Photon
In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...
flux
Flux
In the various subfields of physics, there exist two common usages of the term flux, both with rigorous mathematical frameworks.* In the study of transport phenomena , flux is defined as flow per unit area, where flow is the movement of some quantity per time...
used to measure air glow, is named after him.
Further reading
- Applied Optics vol 3, no. 10, October 1964, special issue devoted to the 3rd and 4th Barons Rayleigh