François Arago
DOI: 10.1063/PT.5.030871
On this day in 1839 François Arago stood before a joint meeting of the French Academy of Sciences and the Academy of Fine Arts in Paris to announce and describe a new method for recording images, the daguerreotype process. Louis Daguerre (shown in the daguerreotype on the left) had invented the process, which entailed first wafting iodine, bromine or chlorine gas over a highly polished silver surface to create a film of silver halide. After exposure and fixing, the resulting daguerreotype was sealed behind glass. The daguerreotype on the right is the first ever of a solar eclipse. It was made on 28 July 1851 at Prussia’s Royal Observatory in Königsberg by a daguerreotypist named Berkowski.
Date in History: 9 January 1839
