Promotional postcard for Maskelyne and Cooke's ?The Artist?s Dream?. John Nevil Maskelyne and George Cooke, presented for the first time to a West End audience an entertainment they had been giving for several years in the province and at the Crystal Palace with considerable success. Maskelyne's invention of the door lock for London toilets required the insertion of a penny coin to operate it, leading to the euphemism to "spend a penny". With John Algernon Clarke, Maskelyne invented "Psycho", the famous whist-playing automaton. At London's Egyptian Hall, Psycho appeared in more than 4000 performances