Benjamin Williamson

“ He also gave some very important applications of the calculus of operations to the calculus of variations, and more especially arrived at an elegant and simple demonstration, by the operational method, of Jacobi's celebrated theorem for distinguishing between maxima and minima values in the application of the calculus of variations. Graves had much literary and artistic taste, and to these were largely due the symmetry and elegance, both of method and results, which are marked characteristics of his mathematical work. ”

“ This he deduced from the more general theorem in spherical conics, the latter being arrived at from its reciprocal theorem—viz. if two spherical conics have the same cyclic arcs, then any arc touching the inner curve will cut off from the outer a segment of constant area. Bertrand, in his great treatise on the integral calculus (1864) , attributed the foregoing fundamental theorem of Graves to Chasles, who had subsequently arrived at it by an independent investigation. ”

“ Having been in 1837 elected a member of the Royal Irish Academy, Graves filled successively the offices of secretary of the council and secretary of the academy, and was elected its president in 1861. He was elected a fellow of the Royal Society in 1880, and the honorary degree of D.C.L. was conferred on him in 1881 by the university of Oxford. He died in Dublin on 17 July 1899 at the advanced age of eighty-six. Graves married in 1840 Selina, daughter of Dr. ”