TIME AND MOTION 75 



cion that we have chosen for kinematics the 

 wrong kind of mathematics. But the verification 

 of the suspicion was greatly delayed by a cer- 

 tain obsession which had taken a strong hold 

 upon the minds of the physicists. I refer to the 

 luminiferous ether. Often in our more carefully 

 cultivated gardens of thought some rank weed 

 grows with such vigor as to stunt the growth of 

 the neighboring useful vegetables. So the scien- 

 tific literature of the nineteenth century was 

 overgrown with a discussion of the ether, its 

 stresses and its strains, its density, its move- 

 ment with the earth or through the earth. A 

 mechanism that we designed to be a servant had 

 become our master ; until now that we are sud- 

 denly freed from this obsession we feel as if 

 awakened from a hideous nightmare. 



Let us examine for a moment this ether 

 theory. Imagine two hostile gunboats anchored 

 in a tidal river. One of them is being shelled by 

 the other, but little damage is done because 

 every time a shell is fired the discharge of the 

 gun produces a wave in the river which, arriv- 

 ing at the other gunboat before the projectile, 

 gives the crew warning to drop behind shelter. 

 But after a time the crew is greatly discon- 



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