Cargill Gilston Knott (nonfiction)

Cargill Gilston Knott.

Prof Cargill Gilston Knott FRS, FRSE LLD (30 June 1856 – 26 October 1922) was a Scottish physicist and mathematician who was a pioneer in seismological research. He spent his early career in Japan. He later became a Fellow of the Royal Society, Secretary of the Royal Society of Edinburgh, and President of the Scottish Meteorological Society.

Knott attended the University of Edinburgh, where he studied alongside James Alfred Ewing. He worked on various aspects of electricity and magnetism, obtaining his doctorate in 1879.

He was appointed as an assistant in Natural Philosophy at Edinburgh University in 1879 and held this post until 1883, when he left to take up a post at Tokyo Imperial University. He was elected as a Fellow of the Royal Society of Edinburgh in 1880 after being proposed by Peter Guthrie Tait, Alexander Crum Brown, John Gray McKendrick, and Alexander Buchan. He won the Society's Keith Prize for the period 1893-95. He served as Secretary 1905-1912 and General Secretary 1912-1922. He was also a founder of the Edinburgh Mathematical Society, taking the chair for its first meeting on Friday 2 February 1883.

Knott replaced Ewing as Professor of Physics and Engineering at Tokyo Imperial University. For the next nine years, he worked closely with Milne, Gray and the Japanese seismologist Fusakichi Omori in establishing a network of recording seismometers across the Japanese Empire. Knott also taught courses in mathematics, acoustics, and electromagnetism at the Tokyo Imperial University.

Knott also undertook the first geomagnetic survey of Japan, assisted by Japanese geophysicist Tanakadate Aikitsu, from which was developed the first earthquake hazard map of Japan. Knott's key contribution was his background in mathematics and data analysis. One of his innovations was to apply the technique of Fourier analysis to the occurrence of earthquakes. Two chapters in his 1908 book The Physics of Earthquake Phenomena were devoted to this subject, which Knott hoped would enable him to deduce the probability of when future earthquakes would occur.

Cargil Knott married Mary Dixon in 1885, becoming the brother-in-law of the literary scholar James Main Dixon.

On the conclusion of his stay in Japan in 1891, he was awarded the Order of the Rising Sun by Emperor Meiji.

Upon his return to Edinburgh, Knott took up the position of a Reader in Applied Mathematics at Edinburgh University and held this post until his death in 1922.

While in Japan, Knott began to develop mathematical equations describing how seismic vibrations are reflected and transmitted across the boundary between seawater and seabed. After returning to Edinburgh University in 1892, he expanded upon this research to describe the behavior of earthquake waves at the interface between two different types of rock.

Knott's equations, derived in terms of potentials, were the first to describe the amplitudes of reflected and refracted waves at non-normal incidence and together with the Zoeppritz equations are now the basis for modern reflection seismology – an important technique in hydrocarbon exploration.

Knott continued his work as a mathematician, including quaternion methods of his professor and mentor Peter Guthrie Tait. When the tight constraints of a single linear algebra began to be felt in the 1890s, and revisionists began publishing, Knott contributed the pivotal article "Recent Innovations in Vector Theory". As M.J. Crowe describes, this paper set straight wayward theorists that expected to find associativity in systems like hyperbolic quaternions.

For a textbook on quaternions, lecturers and students relied on Tait and Kelland's Introduction to Quaternions which had editions in 1873 and 1882. It fell to Knott to prepare a third edition in 1904. By then the Universal Algebra of Alfred North Whitehead (1898) presumed some grounding in quaternions as students encountered matrix algebra. In Knott's introduction to his textbook edition he says "Analytically the quaternion is now known to take its place in the general theory of complex numbers and continuous groups,...". Thus he was aware of the diversity to be encountered in modern mathematical structures, and that quaternions stand as a milestone on the way to others.

He died at his home at 42 Upper Gray Street, Newington, Edinburgh, on 26 October 1922.

Fiction cross-reference

• Crimes against physics
• Crimes against mathematical constants

Nonfiction cross-reference

• Alfred North Whitehead (nonfiction)
• Fusakichi Omori (nonfiction)
• Mathematician (nonfiction)
• Physicist (nonfiction)
• Tanakadate Aikitsu (nonfiction)

External links:

• Cargill Gilston Knott @ Wikipedia