In 1866, owing to changes in the tutorial staff, there was an opening for a new mathematical lecturer in Caius College; and the Maxtor, Dr. Edwin Guest [q. v.], invited Ferrers, who was by far the best mathematician amongst the fellows, to supply the place. His career was thus determined for the rest of his life. For many years head mathematical lecturer, he was one of the two tutors of the college from 1865. As lecturer he was extremely successful. Besides great natural powers in mathematics, he possessed an unusual capacity for vivid exposition. He was probably the best lecturer, in his subject, in the university of his day. He was ordained deacon in 1859 and priest in 1861. On 27 Oct. 1880 he was elected Master of Gonville and Caius College, on Dr. Guest's resignation. He was admitted to the degree of D.D. on 7 June 1881. The honorary degree of LL.D. was conferred on him by the University of Glasgow in 1883.
For more than twenty years he was a member of the council of the senate at Cambridge: first in 1865, and continuously from 1878 to 1893, when increasing infirmity obliged him to decline re-election. In the mathematical tripos he acted as moderator or examiner more often, it is believed, than any one else on record. In 1876 Ferrers was appointed a governor of St. Paul's School, and in 1885 a governor of Eton College. He was elected F.R.S. in 1877.
In his early days Ferrers was a keen university reformer, within the limits in which reform was then contemplated. He heartily supported the abolition of religious tests, and the throwing open of all endowments to free competition; he introduced into his college a more systematic style of examination than was previously in vogue. But he held strongly the old view that a thorough training in mathematics was essential to a sound education. For new subjects, The natural science and mechanical engineering, he had scant sympathy. It was slowly, and probably with some reluctance, that he was induced to accept the principle that distinction in any subject which was recognised and taught in the university gave a valid claim to a scholarship or fellowship.
It was as a mathematician that Ferrers acquired fame outside the university. He made many contributions of importance to mathematical literature. His first book was 'Solutions of the Cambridge Senate House Problems, 1848-51.' In 1861 he published a treatise on 'Trilinear Coordinates,' of which subsequent editions appeared in 1866 and 1876. One of his early memoirs was on Sylvester's development of Poinsot's representation of the motion of a rigid body about a fixed point. The paper was read before the Royal Society in 1869, and pubhshod in their 'Transactions.' In 1871 he edited at the request of the college the 'Mathematical Writings of George Green' (1793–1841) [q. v.], a former fellow. Ferrers's treatise on 'Spherical Harmonics,' published in 1877, presented many original features.
His contribution to the 'Quarterly Journal of Mathematics,' of which he was an editor from 1855 to 1891, were numerous (see list in the Roy. Soc. Cat. Scientific Papers). They range over such subjects as quadriplanar co-ordinates, Lagrange's equations and hydrodynamics. In 1881 he applied himself to study Kelvin's investigation of the law of distribution of electricity in equilibrium on an uninfluenced spherical bowl. In this he made the important addition of finding the potential at any point of space in zonal harmonics. (Quart. Journ. Mathematics, 1881).
In 1879 Ferrers was troubled with the first symptoms of rheumatoid arthritis: this gradually increased until he was rendered a complete cripple. He died at the College Lodge on 31 Jan. 1903, at the age of seventy-three.
On 3 April 1866 he married Emily, daughter of John Lamb [q. v.], dean of Bristol and Master of Corpus Christi College, Cambridge. He had a family of four sons and one daughter. There is a portrait of him, by the Hon. John Collier, in the college.
[Personal knowledge; College and University Records; Dr. Edward Routh's memoir in Royal Society's Proceedings; Ferrers Family History, by C. S. F. Ferrers.]
FESTING, JOHN WOGAN (1837–1902), bishop of St. Albans, born at Brook House, Stourton, Somerset, on 13 Aug. 1837, was eldest son of Richard Grindall Posting by his wife Ehza, daughter of Edward Mammatt, of Ashby-de-la-Zouch. A younger brother, Major-General Edward Robert Festing (b. 1839), R.E., C.B., F.R.S., was director of the science museum, South Kensington (1893–1904). The family, descended from Michael Christian Festing [q. v.], the musician, was of German origin.
Educated at King's school, Bruton, and King's College school, London, Festing graduated B.A. from Trinity College, Cambridge, in 1860 (D.D. jure dig. 1890) as
