**Selig Brodetsky**'s father was Akiva Brodetsky, a synagogue official, and his mother was Adel Prober. Selig was the second son from a large family of thirteen children. His parents were both Russian Jews and his father, tired of the harassment which the family were suffering in Russia, decided to move to London in 1893. He moved to the East End of London, leaving his wife Adel, Selig, and three other young children in Russia. He managed to earn enough to support his family and he wrote asking them to join him in London.

Their journey across Europe was a difficult one described in [3]:-

In London Akiva and Adel could not find permanent work and so they made a living from sowing, with the children earning a little to help by packing matches into boxes. In 1894, when Selig was old enough to begin school, he attended the Jew's Free School in Whitechapel, London. From there, having won a scholarship, he went to the Central Foundation School in Cowper Street, central London, in 1900. In 1902 he came top of the list of those winning intermediate scholarships in London. Further success came when he was awarded a scholarship to study mathematics at Trinity College, Cambridge, matriculating in 1905.Little Selig, then a child of four, retained to the end of his life, a vivid memory of their hiding in a hen-coop till nightfall when a kindly officer in charge of Frontier Forces signalled them out of the darkness that now was the time to cross the frontier. His baby sister started to cry at this critical time but her mother pushed her shawl into the child's mouth and so silenced her.

Brodetsky achieved a very fine record at Cambridge. He graduated in 1908 being placed as bracketed Senior Wrangler (first equal). This in fact made news in a rather disturbing way since [1]:-

In 1910 Brodetsky was awarded the Isaac Newton Scholarship which enabled him to study at Leipzig for his doctorate.Newspaper editorials noted that if the Aliens Act restricting immigration had been passed earlier the Brodetsky family would have been barred.

The University of Leipzig awarded Brodetsky a doctorate in 1913 for a thesis on gravitation and he returned to England in 1914 where he accepted a lectureship in Applied Mathematics at the University of Bristol. On course World War II broke out shortly after this and, in addition to his teaching duties, Brodetsky was assigned as an advisor to a firm making optical equipment, such as periscopes for submarines, for the war. He also collaborated with G H Bryan of University College, Bangor, on mathematical aeronautics, and some of his later publications on this topic are mentioned below.

On 13 January 1919 Brodetsky married Mania Berenblum. They had two children, a son Paul born in 1924 and a daughter Adèle. In 1919 Brodetsky accepted a position as a lecturer at the University of Leeds and he was made a Reader in 1920. He was appointed as the first holder of the Chair of Applied Mathematics at Leeds in 1924.

Brodetsky's work was mainly on aerodynamics and fluid mechanics. His papers include work on the stability of a parachute and fluid flow past circular and elliptic cylinders. He published *The mechanical principles of the aeroplane* in 1921. He also wrote the book *A first course in nomography* in 1920. A nomograph was widely used in engineering and in industry. It is a graphic representation that consists of several lines with scales arranged so that by using a straight edge between known values on two lines an unknown value can be read at the intersection with a third line.

The 5^{th} International Congress for Applied Mechanics was held at Cambridge, Massachusetts, in 1938 and Brodetsky delivered a paper on the equations of motion of an airplane. He expanded his theory further, publishing a major article *The general motion of the aeroplane* in the *Philosophical Transactions of the Royal Society* in 1940. We list the chapter and section headings of this paper to give an indication of the approach Brodetsky took.

**Chapter I.**Longitudinal Motion without Screw Thrust.

Sections: Equations of motion, coefficients of statical and dynamical stability

*k*,

*t*; first approximation. The three standard conditions of the symmetrical aeroplane. Longitudinal stability; usual value of

*t*in standard normal condition. Standard normal condition:

*k*of zero order, Lanchester's phugoids;

*k*small, extended phugoids;

*k*negligible, neutral phugoids; second approximation, Lanchester's phugoids, the loop. Standard diving condition, diving phugoids. Elevator in rotation during motion, flattening out from a dive. Lanchester's phugoids corrected for drag.

**Chapter II.** Longitudinal Motion with Engines in Action.

Sections: Equations of motion, first approximation. Standard normal condition: moderate power, Lanchester's, extended and neutral phugoids, large power, power phugoids, zooming.

**Chapter III.** Three-dimensional Motion.

Sections: Symmetrical aeroplane: equations of motion, first approximation. Standard normal condition; *k* of zero order, three-dimensional phugoids, Immelmann turn; *k* small, extended three-dimensional phugoids; *k* negligible. Standard stalled conditions, the slow spin. Aeroplane with displaced controls, additional moments. Standard normal condition: *k* of zero order; small asymmetry, three-dimensional phugoids; large aileron displacement, the slow roll.

However, it is not only for his contributions to mathematics that Brodetsky is well known. His other contributions are described in [1]:-As a university teacher for students he could hardly be surpassed. Day in, day out, he kept them spell-bound. His subject matter, clarity of exposition, style of delivery, choice of phraseology made an indelible impression on all his listeners whether derived from the Faculties of Arts, Science or Technology. In addition to purely routine standard mathematics, he made mathematical personalities and the history of mathematics live down the centuries by his vivid presentation. ... On one occasion, he gave a lecture on Sir Isaac Newton in a room in the university constructed to seat an audience of250,400turned up and were all accommodated, sitting or standing.

W P Milne was Head of Mathematics at Leeds until he retired in 1946 when Brodetsky took on the role. In 1948 he retired from Leeds University and went to Jerusalem to become the President of the Hebrew University there. This, however, proved much more difficult than Brodetsky expected. He thought he was going to take up a position similar to that of Vice-Chancellor of an English university but many in Jerusalem saw the position as essentially an honorary one, like the Chancellor of an English university. Brodetsky was effective in reforming the Hebrew University but at considerable cost in terms of arguments and disputes. This soon had a detrimental effect on his health and after suffering a heart attack he returned to England in 1951. He resigned as President of the Hebrew University in 1952 and led a quiet life for his last couple of years in contrast to the hectic lifestyle he had led for most of his life.Already at Cambridge Brodetsky had established the pattern of dividing his time between academic work and public service, especially but by no means exclusively for the Jewish community and the Zionist movement. While at Leeds he was active in the affairs of the League of Nations Union(later the United Nations Association)and of the Association of University Teachers. In1928he became a member of the World Zionist Executive and head of its political department in London. In1940he became president of the Board of Deputies of British Jews, the lay head of British Jewry. His election symbolized a democratic revolution, with the communal leadership being taken over from the old-established families by the descendants of the late nineteenth-century immigration. It also demonstrated that Zionism, towards which much of the establishment had been indifferent or hostile, had now the support of the majority of the community, undoubtedly owing to the traumatic events of the Nazi era and the Second World War.

He died at his home in Cromwell Road. London, and was buried in the Willesden Jewish cemetery, London, on 20 May 1954.

**Article by:** *J J O'Connor* and *E F Robertson*

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