Henri Becquerel Discovers Radiation

[Concerning] phosphorescent bodies, and in particular to uranium salts whose phosphorescence has a very brief duration. With the double sulfate of uranium and potassium ... I was able to perform the following experiment: One wraps a Lumière photographic plate with a bromide emulsion in two sheets of very thick black paper, such that the plate does not become clouded upon being exposed to the sun for a day. One places on the sheet of paper, on the outside, a slab of the phosphorescent substan...

 Davy VS Gay-Lussac in the Race to Discover Iodine

He was warmly received by Cuvier, Ampère and Berthollet, but got into an awkward priority dispute with the gifted young chemist Joseph Gay-Lussac. Gay-Lussac, Davy’s exact contemporary, had made a popular name in France with his intrepid ballooning exploits, and had been hard on Davy’s heels with potassium and sodium experiments. Both were now given by the Académie des Sciences a newly isolated substance to analyse: a strange violet crystal recently found as a byproduct of gunpowder man...