S. L. Loney

|birth_place = Chevithorne, Devon, England |death_date = |death_place = Richmond, London |alma_mater = Sidney Sussex College, Cambridge |occupation = Professor, author |organization = Royal Holloway College }} Sydney Luxton Loney, M.A. (16 March 1860 – 16 May 1939) held the esteemed post of Professor of Mathematics at Royal Holloway College, Egham, Surrey, and was also a Fellow of Sidney Sussex College, Cambridge. He authored several mathematics textbooks, many of which have gone into multiple reprints over the years. He is known as an early influence on Srinivasa Ramanujan.

Loney began his schooling at Maidstone Grammar School, then moved to Tonbridge School, where his aptitude for mathematics first became evident. In 1882 he graduated B.A. from Sidney Sussex College, Cambridge as 3rd Wrangler, placing him third in the notoriously rigorous Mathematical Tripos.

After Cambridge, Loney was elected a Fellow of Sidney Sussex College from 1885 to 1891, during which time he deepened his engagement with both teaching and research. In 1888 he accepted the Chair of Mathematics at Royal Holloway College (University of London), a position he held until his retirement in 1920. Beyond his professorship, Loney was active in university governance: he became a Senator of the University of London in 1905, a Trustee and Governor of Royal Holloway in 1920, Chairman of the University’s Convocation in 1923, and Deputy Chairman of its Court in 1929. Locally, he served on the Surrey County Education Committee from 1909 to 1937, was Mayor of Richmond in 1920–1921, and acted as a Justice of the Peace, demonstrating a commitment to public service beyond academia.

Loney’s ''Plane Trigonometry'' and ''The Elements of Coordinate Geometry'' have remained staples in Indian senior‑high curricula and engineering‑entrance coaching, prized for their lucid theory and graduated exercises that build problem‑solving skills. Perhaps most notably, an eleven‑year‑old Srinivasa Ramanujan borrowed ''Plane Trigonometry'' in 1899 and, working through it rigorously over two years, encountered his first substantial piece of formal mathematics outside his school syllabus, a pivotal step in his self‑education. Provided by Wikipedia