Letter from H [Henry] Middleton, 34 Coram Street, London, to Sir Joseph Larmor, St. John's College, Cambridge He sent Larmor a letter but was unable to send the specifications of his patents, which he forwards. He describes them briefly, and his discovery of a fifth way of propelling a submarine, by using the flipper or fin. He sent the copy letter of his 'Daily News' letter to give Larmor an idea of the utility and scope of his invention without having to read the specifications. 5 December 1925