SOMERVILLE, Mary (1780-1872), scientific writer, was the daughter of Admiral Sir William George Fairfax, and was born 26th December 1780 in the manse of Jedburgh, the house of her mother’s sister, wife of Dr Thomas Somerville, author of My Own Life and Times, whose son was her second husband. She received a rather desultory education, and mastered algebra and Euclid in secret after she had left school, and without any extraneous help. In 1804 she married her cousin Captain Samuel Greig, who died in 1806; and in 1812 she married another cousin, Dr William Somerville, inspector of the army medical board, who encouraged and greatly aided her in the study of the physical sciences. After her marriage she made the acquaintance on the Continent and in London of the most eminent scientific men of the time, among whom her talents had attracted attention before she had acquired general fame, Laplace paying her the compliment of stating that she was the only woman who understood his works. Having been requested by Lord Brougham to translate for the Society for the Diffusion of Useful Knowledge the Mécanique Celeste of Laplace, she greatly popularized its form, and its publication in 1831 under the title of The Mechanism of the Heavens at once made her famous. She was elected an honorary member of the Royal Astronomical Society, and her bust by Chantrey was placed in the hall of the Royal Society of London. Her other works are the Connection of the Physical Sciences (1834), Physical Geography (1848), and Molecular and Microscopic Science (1869). Much of the popularity of her writings is due to their clear and crisp style, and the underlying enthusiasm for her subject which pervades them. In 1835 she received a pension of £300 from Government. She died at Naples 28th November 1872. In the following year there appeared her Personal Recollections, consisting of reminiscences written during her old age, and of great interest both for what they reveal of her own character and life and the glimpses they afford of the literary and scientific society of bygone times.