674 HENRY A. KOWLAND 



Have we not another case of a similar nature when a huge gravita- 

 tional mass like that of the earth revolves on its axis? Has not matter 

 a feeble hold on the ether sufficient to produce the earth's magnetism? 



But the experiment of Lodge to detect such an action apparently 

 showed that it must be very feeble. Might not his experiment have 

 succeeded had he used an electrified revolving disc? 



To detect something dependent on the relative motion of the ether 

 and matter has been and is the great desire of physicists. But we 

 always find that, with one possible exception, there is always some com- 

 pensating feature which renders our efforts useless. This one experi- 

 ment is the aberration of light, but even here Stokes has shown that it 

 may be explained in either of two ways: first, that the earth moves 

 through the ether of space without disturbing it, and second, that it 

 carries the ether with it by a kind of motion called irrotational. Even 

 here, however, the amount of action probably depends upon relative 

 motion of the luminous source to the recipient telescope. 



So the principle of Doppler depends also on this relative motion and 

 is independent of the ether. 



The result of the experiments of Foucault on the passage of light 

 through moving water can no longer be interpreted as due to the partial 

 movement of the ether with the moving water, an inference due to 

 imperfect theory alone. The experiment of Lodge, who attempted to 

 set the ether in motion by a rapidly rotating disc, showed no such result. 



The experiment of Michelson to detect the ethereal wind, although 

 carried to the extreme of accuracy, also failed to detect any relative 

 motion of the matter and the ether. 



But matter with an electrical charge holds fast to the ether and 

 moves it in the manner required for magnetic action. 



When electrified bodies move together through space or with refer- 

 ence to each other we can only follow their mutual actions through very 

 slow and uniform velocities. When they move with velocities com- 

 parable with that of light, equal to it or even beyond it, we calculate 

 their mutual actions or action on the ether only by the light of our 

 imagination unguided by experiment. The conclusions of J. J. Thom- 

 son, Heaviside and Hertz are all results of the imagination and they all 

 rest upon assumptions more or less reasonable but always assumptions. 

 A mathematical investigation always obeys the law of the conservation 

 of knowledge: we never get out more from it than we put in. The 

 knowledge may be changed in form, it may be clearer and more exactly 

 stated, but the total amount of the knowledge of nature given out by 



