272 FLUORINE. 



It is evident that, as we see tLe great industrial transformations 

 which take place to-day before our eyes, we can not well dogmatize on 

 the subject. After the preparation of Bessemer steel, the manufacture 

 of manganese in the blast furnace, and the synthesis of alizarin, the 

 chemist dares not- deny the industrial vitality of any reaction of his 

 laboratory. 



When we think of the value which certain metals, such as sodium 

 and potassium, had when Davy prepared them by electrolysis; when 

 we recall that by the process of Gay-Lussac and Thenard they cost 

 some thousands of francs a kilogram, and that to-day, by electrolytic 

 methods, they can be made for not more than 5 francs, we can not say 

 of any chemical reaction that it shall have no industrial uses. 



Only — and here I shall close — it is carious to see how many con- 

 tinuous eiibrts, how many different points of view, are involved in the 

 solution of one of these scientiiic questions; or rather, I should say, 

 to advance one of them, for in reality no subject is ever closed. It 

 remains always open to our successors; we can only add a link to an 

 infinite chain. 



The advancement of science is slow; it is effected only by virtue of 

 hard work and perseverance. And when a result is attained, should 

 we not in recognition connect it with the efforts of those who have pre- 

 ceded us, who have struggled and suffered in advance? Is it not truly 

 a duty to recall the difficulties which they vanquished, the thoughts 

 which guided them; and how men of different nations, ideas, positions, 

 and characters, moved solely by the love of science, have bequeathed 

 to us the unsolved problem? Should not the last comer recall the 

 researches of his predecessors while adding in his turn his contribution 

 of intelligence and of labor? Here is an intellectual collaboration con- 

 secrated entirely to the search for truth, and which continues from 

 century to century. 



This scientific patrimony which we ever seek to extend is a part of 

 the fortune of humanity; we should preserve it with full recognition of 

 those who gave it the warmth of their hearts and the best of their 

 intelligence. 



