**Nikolai Kochin** was a Russian mathematician who was one of the founders of modern dynamic meteorology.

- When Nikolai Evgrafovich was still very young he already showed his talent for mathematics by quickly learning basic arithmetic.
- She had purchased university texts on geometry and on analysis and Kochin read these books while he was at the high school.
- In early 1917, while Kochin was nearing the end of his secondary education, the Russian Revolution broke out in Petrograd.
- Kochin, however, was able to complete his school education in 1918 and in the same year entered Petrograd University which had been renamed 1st Petrograd State University shortly before he began his studies.
- A White Army led by Nikolai Nikolayevich Yudenich marched from Estonia and attempted to capture Petrograd.
- Kochin was part of the Red Army, led by Trotsky, that defeated this White Army at Gatchina near Petrograd.
- In November 1919 Kochin was part of the Red Army that captured Yamburg, about 100 km south west of Petrograd, following the withdrawal of Yudenich's White Army from the town.
- Kochin enlisted as a cadet in the Artillery Academy in Petrograd in 1920.
- Kochin was sent with the Bolshevik army to put down the Kronstadt rebellion.
- In April 1922, with stability returning to the country, Kochin was discharged from the army.
- Once he left the army Kochin joined Aleksandr Aleksandrovich Friedmann's Mathematics Department in the Main Geophysical Observatory in Petrograd and, at the same time, continued his studies in the Mathematics Department of the Physics and Mathematics Faculty of Petrograd University.
- Kochin was hired as a computation assistant, but he was not given any routine computation tasks (except that he was once involved in a group task of supplementing ballistic charts).
- Soon Nikolai Kochin solved two problems formulated by Friedmann in his Master's dissertation 'The Hydrodynamics of a Compressible Fluid'.
- Note that the Russian Master's Degree at this time was equivalent to the modern Ph.D. Kochin graduated from the University in 1923.
- On 17 March 1924 Kochin gave a talk on A Defant's article 'On the theory of the polar front'.
- Soon Kochin's article was published, specifying Defant's solution.
- This article was the start of a major series of works by Kochin, resulting in the creation of the linear theory of cyclogenesis in the early 1930s.
- As an undergraduate Kochin had already met Pelageia Polubarinova and the two found that they had much in common, as both were undertaking research on meteorology, gas dynamics and shock waves in compressible fluids.
- Friedmann died in September 1925 and, after this, Kochin took over his role as the leading Russian meteorologist.
- At this time Kochin worked in the Department of Mechanics and this resulted in his move to Moscow where the V A Steklov Mathematics Institute was based.
- Kochin became a professor at Moscow University in 1935 and worked there for the rest of his life.
- Kochin was awarded a Doctorate in Physics and Mathematical Sciences in 1935 (equivalent in standard to the D.Sc. or habilitation).
- The Molotov-Ribbentrop non-aggression pact between Germany and the Soviet Union meant that the initial years of the war had little effect on life in Moscow and Kochin was able to continue his high work rate.
- Kochin, however, remained in Moscow carrying out military research.
- By 1943 the German army had suffered defeats by Soviet troops and Moscow was safe enough for Kochina to return.
- This she did, but Kochin became ill and died before the end of the war.
- At the time of his death he had been in the middle of delivering lecture courses and Kochina took over the courses and completed giving them.
- As we have seen, Kochin's research was on meteorology, gas dynamics and shock waves in compressible fluids.
- He wrote the textbook 'Vector Calculus and the Principles of Tensor Calculus', many editions of which have been published, and finally, together with Ilia Afanasevich Kibel (1904-1970) and Nikolai Vladimirovich Roze, wrote the outstanding two-volume course 'Theoretical Fluid Mechanics', which has been, and continues to be, used to teach many generations of Russian mechanics.
- Kochin also edited the works of Ivan Aleksandrovich Lappo-Danilevskii (1896-1931), who was an expert on applying matrix theory to differential equations, and of Aleksandr Mikhailovich Lyapunov.
- Kochin was an enthusiastic member of the Moscow Mathematical Society and served as its secretary from 1938 to 1940.

Born 6 May 1901, St Petersburg, Russia. Died 31 December 1944, Moscow, USSR.

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Origin Russia

**Oâ€™Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive