**PROF. SIR HAROLD JEFFERYS**

If not a son of the village, Harold Jefferys was certainly a grandson of the village. A scientist, mathematician, astronomer, and geophysicist of worldwide renown.

Harold's grandparents and then his uncle ran the Shoulder of Mutton Inn here in the village for almost 70 years. His father lived at the Inn and was educated at the village school under the headmaster Jacob Barker. Later Harold's father became a teacher at Fatfield in Co. Durham and it was there that Harold was born.

Harold Jeffreys attended school at Fatfield then, in 1903, he was awarded a scholarship to attend Rutherford College in Newcastle- upon- Tyne. In 1907 he went to Armstrong College, also in Newcastle (which later became Newcastle University). At the time Jeffreys entered the College it was a part of Durham University. There he studied mathematics, physics, chemistry, and geology, graduating in 1910 with distinction in mathematics.

He went to St John's College Cambridge, after leaving Newcastle, having obtained one of four mathematics scholarships. He became a fellow of St John's College, Cambridge in 1914 and remained a fellow all his life.

Jeffreys worked in the Cavendish Laboratories on war-related work from 1915 until 1917. He joined the Meteorological Office from 1917 to 1922 where he worked on hydrodynamical problems. He returned to Cambridge and he lectured there in mathematics until 1932. Jeffreys was to remain on the staff at Cambridge, but not as a mathematician. From 1932 to 1946 he taught geophysics there, then he became Plumian Professor of Astronomy.

As a lecturer Jeffreys, despite his personal charm and enthusiasm, had a poor reputation. Jeffreys's work in diverse areas of science had mathematical applications as their link. In geophysics, he studied earthquakes and the circulation of the atmosphere. As a result of his study of earthquake waves, Jeffreys became the first to claim that the core of the Earth is liquid.

In astronomy he studied the outer planets, proposing models for their structures. He also studied the origin of the solar system

He was awarded honours from the Royal Astronomical Society (1937), from the Royal Society of London (1948) and was knighted in 1953. The 1948 award from the Royal Society of London was their Royal Medal which they awarded:- *... for distinguished work in geophysics and his important contributions to the astronomy of the solar system.*

The Royal Society awarded him their Copley Medal in 1960:- *... in recognition of his distinguished work in many branches of geophysics, and also in the theory of probability and astronomy.*

Among Jeffreys's works is *The Earth: Its Origin, History and Physical Constitution *(1924), *Earthquakes and Mountains* (1935) and he wrote *Methods of Mathematical Physics *(1946) jointly with his wife Bertha Jeffreys. They state clearly in the preface that their aims are *to provide an account of those parts of pure mathematics that are most frequently needed in physics. *

** The man who discovered the centre of the earth was molten**** and whose mathematical tables are still used today **** to discover**

** the epicentre of earthquakes.**

In pure mathematics he studied operational methods (where he improved on Heaviside's operational calculus and Laplace transforms). Cartesian tensors and asymptotic approximations. In addition to *Methods of Mathematical Physics* other contributions of his to pure mathematics are contained in Theory of Probability(1939). His work in probability is developed along Bayesian lines and again aimed at application in the physical sciences.

Jeffreys's character is well illustrated the following quotes give a picture:-

*"For many years he smoked intensely and in Cambridge he bicycled everywhere until over 90, even after he had broken his wrist in an accident. ... Although uncommunicative, Harold could be a good talker ... though shy, [he] was at heart a sociable man ..."*

*"Harold was held in respect, indeed reverence, in many countries, but in those who knew him well it was more than respect or reverence that he inspired, it was affection, affection for a man who for all his impressive abilities as a mathematician, for all his wide and deep knowledge, for all he had done to develop geophysics, was at heart a very friendly, unassuming person, quite free of pride or pretension."*

Harold Jefferys married Bertha Swirles, also a Cambridge Don, in 1940, they had no children.

Harold was awarded the following awards:-

Fellow of the Royal Society..........................1925

Royal Society Royal Medal...........................1948

Royal Society Bakerian Lecturer...................1952

Fellow of the Royal Society of Edinburgh...... 1953

Royal Society Copley Medal..........................1960

RSS Guy Medal in Gold.................................1962

Older readers may well remember Sir Harold Jefferys on one of his regular visits to Longhorsley as he walked around the village in his shorts, and always with his trusty camera slung over his shoulder.

Harold's parents are buried in Longhorsley churchyard and on their grave is a plaque, it reads:-

*"In loving memory of Sir Harold Jefferys F.R.S.*

* their only son born Fatfield 1891 died Cambridge *

*1989 beloved husband of Bertha."*

Source: The Papers and correspondence of Sir Harold Jeffreys *St Johns Col. LibraryCambridge* * GBR/0275/Jeffreys*

**Sir Harold Jefferys F.R.S. **