Sir William, an eminent British statesman, was the lineal descendant of an old Cornish family of extensive landed property, and was born in London in 1810. In his thirteenth year he lost his father, and succeeded to the family estate and baronetcy. He studied at Cambridge, but was rusticated there for challenging his tutor to mortal combat. After spending some time at the university of Edinburgh, engaged in the study of mathematics, classics, and metaphysics, he repaired to Germany. There his attention was chiefly devoted to philology and history. He then made the usual tour of Europe, and returned to England in 1831. In the same year, before he had attained his majority, he delivered an earnest and elaborate speech in favour of parliamentary reform at a Cornish county meeting. This first appearance of his in public prepossessed the local Liberals so much in his favour, that in 1832 he was returned without opposition as one of the members of Parliament for the eastern division of Cornwall. He was re-elected by his constituents in 1835; but in 1837 so powerful had the reaction against his opinions become, that he despaired of regaining his seat. He therefore became a candidate for Leeds, and was successful. On the dissolution of 1841, the clouded prospects of his party deprived him of all hope of being returned by his former constituency, and induced him to retire without a contest from parliamentary life. Sir William Molesworth devoted the next four years to a close study of politics and social economy. In 1845 he was again on the field as a candidate for Southwark. His bold advocacy of the Maynooth grant excited formidable opposition; but his open and conscientious conduct at length won the day, and he continued to represent this constituency during the rest of his life. Ever since his entrance into Parliament Sir William Molesworth had been gradually acquiring the reputation of a clear, sound, logical, and weighty speaker. He had directed all his energies to the reformation of the colonial office, had aroused the attention of Parliament to that subject, had explained with great ability the principles of colonial self-government, and had finally convinced statesmen and the public of the truth of his views. It was therefore with general approbation that he was appointed First Commissioner of Public Works in January 1853, and Colonial Secretary in July 1855. But this latter office he did not long enjoy. He died of a low gastric fever in October 1855.