The Evolution of the Sciences 



Matter and ether, these are the materials 

 with which our scientific theories have tried to 

 construct an image of the world. This struc- 

 ture was being built up gradually and 

 methodically, when at the end of the nine- 

 teenth century an event, which all must 

 remember, gave a great impulse to the 

 evolution of science and imparted to it 

 an unexpected turn. The great discovery of 

 Rontgen, and those of Becquerel and of Curie, 

 revealed to us a new world. Scientists, who 

 were at first dazed by the mysterious X of the 

 new rays, are gradually recovering equanimity, 

 thanks chiefly, it must be said, to the audacity 

 of the physicists of the Cambridge school under 

 the leadership of Professor J. J. Thomson, whose 

 labours have recently met with their deserved 

 reward in the shape of a Nobel prize. All our 

 views regarding matter have to-day been so 

 completely remoulded that before proceeding 

 farther we must devote some space to the ex- 

 planation of this metamorphosis. 



Let us consider a Rontgen ray bulb. It 

 consists of a glass vessel into which penetrate 

 two metal wires connected to two platinum 



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