264 FLUORINE. 



the close of their investigation he spent three years at Genoa and 

 returned still suffering. As for Louyet, carried away by his researches, 

 he took insufficient precautions to avoid the irritating- action of the acid 

 vapors, and paid with his life for his devotion to science. 



These researches of Louyet led Fremy, about the year 1850, to take 

 up again the question of the isolation of fluorine. Fremy first studied, 

 systematically, the metallic fluorides. He proved the existence of 

 numerous fluohydrates of fluorides, and ascertained their properties 

 and composition. Next he caused many gaseous substances to react 

 upon different fluorides, the action of chlorine and of oxygen being 

 studied with care. Finally, all his attention was drawn l;o the electro- 

 lysis of metallic fluorides. 



Most of these experiments were performed in vessels of x)latinum, at 

 temperatures which were sometimes very high. When, after the gen- 

 eral examination of the fluorides, Fremy studied the action of chlorine 

 upon the fluorides of lead, antnnouy, mercury, and silver, he showed 

 clearly that it was almost impossible then to obtain these comi^ounds 

 in a condition of absolute dryness. Hence we can understand why, in 

 his electrolytic researches, this chemist devoted his attention mainly to 

 calcium fluoride. 



Having seen that many fluorides retained water most tenaciously, he 

 fell back upon fluor spar, which often occurs in nature very pure and 

 absolutely dry. This fluoride of calcium, liquefied at a high tempera- 

 ture, he sought to electrolyze in a platinum vessel. 



Under these conditions the metal calcium is carried to the negative 

 pole, while around the platinum rod wliich formed the negative electrode, 

 and which was rapidly corroded, there was visible a boiling, indicating 

 the escape of a new gas. 



Undoubtedly, in these experiments, fluorine was set free; but con- 

 sider that the electrolysis was effected at the temperature of a bright 

 red heat. How difficult experimentation must become under such 

 conditions. How is it iDossible to collect the gas or to ascertain its prop- 

 erties 1 This gaseous body displaces iodine from the iodides, but after 

 a few experiments the alkaline metal, set at liberty, pierces the plati- 

 num walls of the apparatus, the latter becomes useless, and all must be 

 begun anew. 



Far from being discouraged by his failures Fremy, on the contrary, 

 brought to his work an inconceivable perseverance. He varied his 

 experiments, modified his apparatus; the difficulties only encouraged 

 him to continue his labors. 



Two important facts at once stood out by themselves. One entered 

 immediately into the domain of science; the other seems to have 

 attracted much less attention. 



The first was the preparation of pure, anhydrous hydrofluoric acid. 

 Until the researches of Fremy, the acid absolutely deprived of water 

 was unknown. Having prepared and analyzed the fluohydrate of 



