After the death of both George III and Banks in 1820, the botanic gardens entered a period of decline until 1841, when they passed from the Crown to the Government. The first director, William Hooker (d 1865), greatly expanded the grounds; he amalgamated the botanic gardens and pleasure grounds and opened them to both the public and botanists. Several structures were built to house specimens from the British Empire: the Palm House (1845-1848), designed by Decimus Burton and the engineer Richard Turner (ca. 1798-1881), was a highly innovative structure of wrought- and cast-iron (110.3 x 32.3 x 18.9 m), covered entirely in curved glass. The enormous Temperate House (1859-1899), also by Burton, is of conventional design.