Jean-Baptiste Dumas, who was president of the National Society for the Encouragement of Science (Société d'encouragement pour l'industrie nationale) and a chemist, put his laboratory at Daguerre's disposal. According to Austrian chemist Josef Maria Eder, Daguerre was not versed in chemistry and it was Dumas who suggested Daguerre use sodium hyposulfite, discovered by Herschel in 1819, as a fixer to dissolve the unexposed silver salts.
Jean-Baptiste Dumas, who was president of the National Society for the Encouragement of Science (Société d'encouragement pour l'industrie nationale) and a chemist put his laboratory at Daguerre's disposal. According to Austrian chemist Josef Mari,a Eder, Daguerre was not versed in chemistry and it was Dumas who suggested Daguerre use sodium hyposulfite, discovered by Herschel in 1819, as a fixer to dissolve the unexposed silver salts.