On his death, the titles passed to his son, the second Marquess. He represented Northampton in Parliament but is best remembered as a patron of science and the arts. Between 1838 and 1848 he served as President of the Royal Society. He was also instrumental in helping the new College of Preceptors (College of Teachers) of London receive its Royal Charter. Lord Northampton married Margaret Douglas-Maclean-Clephane, daughter of Major-General Douglas Maclean Clephane. He was succeeded by his eldest son, the third Marquess. In 1831 he assumed by Royal licence the additional and principal surname of Douglas. When he died the titles were inherited by his younger brother, the fourth Marquess. He was an admiral in the Royal Navy. Lord Northampton assumed in 1851 by Royal licence the additional surname of Maclean and in 1878 upon succeeding to the titles that of Douglas.