Alfred George Greenhill, born November 29, 1847, elected F. R. S. in 1888, died February 10, 1927. After a distinguished career at Christ’s Hospital, and at St. John’s College, Cambridge, he was second wrangler in 1870, but bracketed with the Senior Wrangler, Richard Pendlebury, of his own college, in the Smith Prize Examination. In the same year he was elected Fellow of the College. Shortly afterwards he was appointed to the Royal Indian Engineering College, Cooper’s Hill. In 1873, however, he was made Fellow and Lecturer at Emmanuel College, Cambridge. This he left in 1876 to become Professor of Mathematics to the Advanced Class of Artillery Officers at Woolwich. After more than thirty years’ government service he retired, and the rest of his life was spent, as a bachelor, in London, first in New Inn, and later in Staple Inn; in his later years, he was the recipient of a Civil List Pension. During his residence in London he was very active in mathematical and scientific circles; he became a Fellow of the Royal Society in 1888, and received a Royal Medal from that Society in 1906; he was awarded the De Morgan Medal by the London Mathematical Society in 1902; he had served as President of this Society 1890-92. He was on the Councils of both societies, of the Royal Society, in 1896, 1897, and of the London Mathematical Society for many years. He also became a corresponding member of the Académie des Sciences (Paris), and a foreign member of the Accademia dei Lincei (Rome). He was knighted in 1908, on his retirement from Woolwich. His original contributions to knowledge were mainly to Dynamics, to Hydrodynamics, and to Elasticity. Of the great value of these a highly appreciative account is given by an expert, in Prof. Love's Obituary Notice of Greenhill, “Journal of the London Math. Soc.,” vol. iii, pp. 29 and 30, 1928. Prof. Love writes as follows.