text: Progress in isolating the element was slowed by the exceptional dangers of generating fluorine:  several 19th century experimenters, the "fluorine martyrs", were killed or blinded. Humphry Davy, as well as the notable French chemists Joseph Louis Gay-Lussac and Louis Jacques Thénard, experienced severe pains from inhaling hydrogen fluoride gas; Davy's eyes were damaged. Irish chemists Thomas and George Knox developed fluorite apparatus for working with hydrogen fluoride, but nonetheless were severely poisoned. Thomas nearly died and George was disabled for three years. French chemist Henri Moissan was poisoned several times, which shortened his life. Belgian chemist Paulin Louyet and French chemist  tried to follow the Knox work, but they died from HF poisoning even though they were aware of the dangers.
  Initial attempts to isolate the element were also hindered by material difficulties:  the extreme corrosiveness and reactivity of hydrogen fluoride (and of fluorine gas) as well as problems getting a suitable conducting liquid for electrolysis. Davy tried to electrolyze HF but had to stop because the electrodes were damaged. He then shifted to (unsuccessful) chemical reactions.
  Edmond Frémy thought that passing electric current through pure hydrofluoric acid (dry HF) might work. Previously, hydrogen fluoride was only available in a water solution. Frémy therefore devised a method for producing dry hydrogen fluoride by acidifying potassium bifluoride (KHF). Unfortunately, pure hydrogen fluoride did not pass an electric current. Frémy also tried electrolyzing molten calcium fluoride and probably produced some fluorine (since he made calcium metal at the other electrode), but he was unable to collect the gas.
  English chemist George Gore also tried electrolyzing dry HF and may have made small quantities of fluorine gas in 1860. He reported an explosion after running his cell (hydrogen and fluorine recombine dramatically), but he recognized that an oxygen leak could have also caused the reaction.