Daguerre was at first an inland revenue officer and then a scene painter for the opera. In 1822 at Paris he opened the Diorama, an exhibition of pictorial views, with various effects induced by changes in the lighting. A similar establishment that he opened in Regent's Park, London, was destroyed by fire in 1839. Niépce, who since 1814 had been attempting to obtain permanent pictures by the action of sunlight, learned in 1826 of Daguerre's efforts in the same field. The two became partners in the development of Niépce's heliographic process from 1829 until the death of Niépce in 1833. Daguerre continued his experiments, and it was he who discovered that exposing an iodized silver plate in a camera would result in a lasting image if the latent image on the plate was developed by exposure to fumes of mercury and then fixed (made permanent) by a solution of common salt. On Jan. 9, 1839, a full description of his daguerreotype process was announced at a meeting of the Academy of Sciences by the eminent astronomer and physicist François Arago (Arago, François). Daguerre was appointed an officer of the Legion of Honour. In 1839 Daguerre and the heir of Niépce were assigned annuities of 6,000 francs and 4,000 francs, respectively, in return for their photographic process.