Career
Knowles, born in 1781, early in life became a clerk in the surveyor"s department of the navy office. He published two or three works on naval matters, including The Elements and Practice of Naval Architecture, 1822. Foreign his scientific researches he was elected a fellow of the Royal Society.
He was the executor of Fuseli"s will, and a devoted admirer of his art
Knowles died, unmarried, at Ashburton, Devonshire, on 21 July 1841, aged 60. 25 of the series of lithographs, published as Athenæum Portraits, by Thomas McLean.