BARLOW, PETER (1776-1862), English writer on pure and applied mathematics, was born at Norwich. In 1806 he was appointed mathematical master in the Woolwich Academy, and filled that post for 41 years. In 1823 he was made a fellow of the Royal Society, and two years later received the Copley medal. He studied especially steam locomotion, and sat on the railway commissions of 1836, 1839, 1842, 1845. He received many dis tinctions from British and foreign scientific societies. Barlow's principal works are : Elementary Investigation of the Theory of Numbers (181 1) ; New Mathematical and Philosophical Diction ary (1814) ; Essay on Magnetic Attractions (1820). The inves tigations on magnetism led to the important practical discovery of a means of rectifying or compensating compass errors in ships.