James Douglass was the first man to hold the permanent post of Engineer-in-Chief to Trinity House 1863-92. He accompanied his father Nicholas as assistant in building the ill-fated iron tower on the Bishop Rock designed by James Walker in 1847, and subsequently the stone one which replaced it. He was resident engineer on the Smalls from 1855 to its completion in 1861 when he was moved to the Wolf Rock. After his appointment as Engineer-in-Chief he designed twenty new towers including the new Eddystone and the reconstructed Bishop Rock. In 1864 he invented the helically framed lantern.