76 THE LIFE OF PASTEUR 



by travelling; such geography is remembered because one has 

 seen the places. In the same way your sons will not forget 

 what the air we breathe contains when they have once analysed 

 it, when in their hands and under their eyes the admirable 

 properties of its elements have been resolved.'' 



After stating his wish to be directly useful to these sons of 

 manufacturers and to put his laboratory at their disposal, he 

 eloquently upheld the rights of theory in teaching — ■ 



"Without theory, practice is but routine born of habit. 

 Theory alone can bring forth and develop the spirit of inven- 

 tion. It is to you specially that it will belong not to share the 

 opinion of those narrow minds who disdain everything in 

 science which has not an immediate application. You know 

 Franklin's charming sajdng? He was witnessing the first 

 demonstration of a purely scientific discovery, and people 

 round him said: 'But what is the use of it?' Franklin 

 answered them; 'What is the use of a new-bom child?* 

 Yes, gentlemen, what is the use of a new-born child? And 

 yet, perhaps, at that tender age, germs already existed in you 

 of the talents which distinguish youl In your baby boys, 

 fragile beings as they are, there are incipient magistrates, 

 scientists, heroes as valiant as those who are now covering 

 themselves with glory under the waUs of Sebastopol. And 

 thus, gentlemen, a theoretical discovery has but the merit of 

 its existence: it awakens hope, and that is all. But let it be 

 cultivated, let it grow, and you wiU see what it will become. 



''Do you know when it first saw the light, this electric 

 telegraph, one of the most marvellous applications of modern 

 science? It was in that memorable year, 1822: Oersted, a 

 Danish physicist, held in his hands a piece of copper wire, 

 joined by its extremities to the two poles of a Volta pile. On 

 his table was a magnetized needle on its pivot, and he suddenly 

 saw (by chance you will say, but chance only favours the mind 

 which is prepared) the needle mcve and take up a position 

 quite different from the one assigned to it by terrestrial mag- 

 netism. A wire carrying an electric current deviates a mag- 

 netized needle from its position. That, gentlemen, was the 

 birth of the modern telegraph. Franklin's interlocutor might 

 well h^ve said when the needle moved: 'But what is the use 

 of that?^ And yet that discovery was barely twenty years old 

 when it produced by its application the almost supernatural 

 effects of the electric telegraph!" 



