Abraham Robertson

Abraham or Abram Robertson FRS (4 November 1751 – 4 December 1826), was a Scottish mathematician and astronomer. He held the Savilian Chair of Geometry at the University of Oxford from 1797 to 1809.
Robertson was born at Duns, Berwickshire, the son of Abraham Robertson, “a man of humble station”. He attended school at Great Ryle in Northumberland, and later at Duns. At age 24, he moved to London, he had hopes of travelling to the East Indies, but his patron died. 
He took himself alone to Oxford, where he sought to finance himself by opening an evening school for mechanics. This failed, and he served for a while as an assistant to John Ireland, a local apothecary. He then gained patronage from John Smith (1721—1796), the Savilian professor of geometry. Robertson completed a Bachelor of Arts in 1779 and completed his Master in Arts in 1782.
In 1784, he deputized for Smith, who was then acting as a physician at Cheltenham and then followed Smith as Savilian professor of geometry. His lectures were considered clear, and he was always anxious to encourage his pupils. Thus in 1804 he printed a demonstration of Euclid v, Definition 5, for the benefit of beginners.
In 1789, Robertson was presented by the dean and canons of Christ Church to the vicarage of Ravensthorpe, near Northampton, but his principal residence was still in Oxford. He married, about 1790, Miss Bacon of Drayton in Berkshire, who died a few years after he became professor. They had no children.
In 1795, the Royal Society elected him a fellow in recognition of his work on conic sections.
Robertson died on 4 December 1826 at the Radcliffe Observatory, Oxford, and was buried in the churchyard of St Peter-in-the-East.
Robertson's chief works were the following:
References.
W. F. Sedgwick, "Abram Robertson (1751-1826)", rev. Alan Yoshioka, Oxford Dictionary of National Biography, Oxford University Press, 2004