**Emory McClintock**soon dropped his first name of "John" (to avoid confusion with his father who was known as John McClintock) and was known by his middle name of "Emory". His mother was Caroline Augusta Wakeman and his father was the Reverend John McClintock. As well as being a clergyman in the Methodist Episcopal Church, the Reverend McClintock taught mathematics, Greek, and Latin at Dickinson College, Carlisle, Pennsylvania.

Up to the age of thirteen, Emory was taught at home, then he spent only one year at high school before entering the College where his father taught. He studied at Dickinson College from 1854 until he entered Yale University in 1856. The move to Yale took place because his father moved north at this time and Emory went with him. He then studied at Columbia College in New York (later Columbia University) from 1857 receiving his A.B. in 1859. In the following academic year, 1859-60, he taught mathematics at Columbia College as a tutor before deciding to continue his studies in Europe.

McClintock spent the latter part of 1860 studying chemistry at the University of Paris and then in the following year he studied at Göttingen. Much had happen in American politics during the time that McClintock had been in Europe. In 1860 Lincoln was elected President and this acted as a signal for secession. First was South Carolina on 20 December and other southern states followed. In February 1861, before Lincoln's inauguration, six states set up a government in the south. By April 1861 the civil war had broken out and by February 1862 McClintock felt that he had to return to support his country. By the time McClintock returned to the United States the South had already introduced conscription and the Union was encouraging volunteers for military service although they had not yet introduced conscription. McClintock immediately decided to volunteer for the Union army and was offered a post as a second lieutenant in the Topographical Engineers. Before he could take up the post, however, he suffered severe sunstroke which prevented him from joining the army. He slowly recovered his health over quite a long period.

He represented the US Consul in England from 1863 to 1866 when he became associated with a banking firm in Paris during 1867. Returning to the United States he became an actuary for the Asbury Life Insurance Company in New York in 1867, putting his mathematical skills to good use. McClintock married Zoe Darlington, daughter of John Darlington from Yorkshire, England, on 22 January 1868; they had one son, John, born in 1872, who went on to a prominent career in the United States military. He moved to a position in the Northwestern Mutual Life Insurance Company of Milwaukee in 1871, before becoming an actuary in the Mutual Life Insurance Company in New York in 1889. He became vice-president of the Company in 1906 and held this post until he retired in 1911. After he retired he still acted as a consulting actuary until 1916.

In fact McClintock was for many years the leading actuary in America. He published 30 papers between 1868 and 1877 on actuarial questions. His publications were not confined to questions relating to life insurance policies however. He published about 22 papers on mathematical topics. One paper treats difference equations as differential equations of infinite order and others look at quintic equations which are soluble algebraically. He published *A simplified solution of the cubic* in 1900 in the *Annals of Mathematics*. Another work, *On the nature and use of the functions employed in the recognition of quadratic residues* (1902), published in the *Transactions of the American Mathematical Society*, is on quadratic residues.

Archibald writes [1]:-

In 1889 when McClintock took up his actuarial post with the Mutual Life Insurance Company in New York, the New York Mathematical Society was just coming into existence. McClintock joined the Society in December 1889 and was elected vice-president of the Society. In the following year he was elected president and he has the distinction of being the only president of the Society to serve for four years.McClintock is known to have expressed regret that he had not followed an academic career, which would have permitted him to give a large share of his time to research... In such a direction he would probably have gone far.

During McClintock's presidential term, Klein visited the Society and talked on non-euclidean spherical trigonometry. Study also addressed the Society during McClintock's term as president and talked on his work with Engel. When McClintock's term ended he gave the first presidential address to the Society on *The past and future of the Society* [7]:-

Among the honours which McClintock received, many were for his mathematical work on the Calculus of Enlargement [7]:-... he was a great help in establishing the Bulletin of the American Mathematical Society and the Transactions of the American Mathematical Society; contemporary accounts have suggested that his role was not limited to merely advice but also extended to financial assistance ... It is known that he made substantial donations to the Society's library.

For this work he received honorary degrees, including a Ph.D. from the University of Wisconsin (1884) and LL.D. degrees from Yale (1892) and Columbia (1895).... in his "An Essay on the Calculus of Enlargement"(1879)... he sought to develop a unified theory of the calculus of finite differences and the differential calculus. This led he to restate difference equations as differential equations of infinite order.

Before ending this biography we should mention McClintock's hobbies of genealogy and military history. McClintock:-

His researches into the American Revolutionary War and George Washington led him to address the Washington Association of New Jersey. On his death he left an unfinished manuscript... was able to trace his family back through several centuries. A series of notebooks reflecting specific research into the Baskerville, Kemble, McClintock, and Wakeman families record the lines of descent through each ancestral surname. Several folders of handwritten notes for various family surnames, including Goodyear, Longacre, Lowry, and Ward, are arranged alphabetically by surname ...

*The Fall of 1779*concerning his research into the life of George Washington.

After the death of his first wife Zoe, McClintock married Isabella Bishop, daughter of the Honourable James Bishop, of New Brunswick, New Jersey.

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

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