(1780-1872) Mathematician and writer on science, daughter of Admiral Sir William G. Fairfax, born at Jedburgh, was twice married, first to Mr. Greig, an officer in the Russian Navy, and second to her cousin Dr. William S. Although she had early manifested a taste for study, and specially for science, she had, until after the death of her first husband, little opportunity of following out her favourite subjects. With Dr. Somerville, who was in full sympathy with her scientific tastes, she went to reside in London, and there her talents made her known in scientific circles. In 1823 she was requested by Lord Brougham to popularise the Mechanique Celeste of La Place. This she did with great success, publishing her work as The Celestial Mechanism of the Heavens (1830). She also puborn The Connection of the Physical Sciences (1834), and other works. She received a pension from Government, and died aged 92 at Naples, where she had resided for the last ten or twelve years of her life.