FLUORINE. 271 



sodium become iucaudesceiit, yielding fluorides. In general, liowever, 

 the metals are attacked less vigorously tliau tbe metalloids. This, we 

 tbink, is due to a superficial formation of fluoride wbicli hinders fur- 

 ther attack. Powdered iron and manganese burn in the gas with a 

 shower of sparks. 



Organic bodies are violently attacked. A i)iece of cork placed near 

 the mouth of the ])latinum exit tube carbonizes at once and inflames. 

 Alcohol, ether, benzene, turpentine, and ijetroleum take fire upon con- 

 tact with fluorine. 



Working under good conditions one can obtain from each pole of the 

 apparatus two to four liters of gas per hour. 



When the experiment has lasted for several hours and the quantity 

 of hydrofluoric acid remaining at the bottom of the U tube is not suffi- 

 cient to separate the two gases they recombine in the apparatus with a 

 violent detonation. 



We are assured, by direct experiment, that a mixture of ozone sat- 

 urated with hydrofluoric acid produces none of the reactions just 

 described. The same is true of gaseous hydrofluoric acid. It may be 

 added that the hydrofluoric acid employed, and also the fluohydrate, 

 were absolutely free from chlorine. Finally, it can not be objected that 

 the new gas might be a perfluoride of hydrogen; for, passed over iron 

 heated to redness in a platinum tube it is completely absorbed, without 

 liberation of hydrogen. 



lu the most recent investigations I have found that it is possible to 

 make these experiments in an apparatus of copper, constructed like 

 the platinum device which is before you. 



By the electrolysis of hydrofluoric acid rendered conductive with the 

 acid fluoride of potassium, we have obtained, at the negative pole, 

 hydrogen, and at the positive pole the continuous evolution of a gas 

 having new properties and endowed with very energetic affinities; that 

 gas is fluorine. We have been able to determine its density, its color, 

 and its spectrum, and to study its action upon both elements and 

 compounds. 



Now that we know the chief properties of fluorine, now that the 

 element has been isolated, I am convinced that in spite of its energetic 

 reactions, new means for its preparation will be discovered. 



We may even suppose thai purely chemical methods for the j)repara- 

 t'ion of fluorine may be found, which shall give a better yield than the 

 electrolytic x)rocess. 



Will fluorine ever have practical applications'? 



It is very difficult to answer this question. I may, however, say in 

 all sincerity that I gave this subject little thought when I undertook 

 my researches, and I believe that all the chemists whose attempts pre- 

 ceded mine gave it no more consideration. 



A scientific research is a search after truth, and it is only after dis- 

 covery that the question of applicability can be usefully considered. 



