NEW CONCEPTIONS IN SCIENCE 



the higher the degree of exhaustion in his tubes, 

 called now Crookes tubes the world over, the less 

 was the electrical force required to bridge the 

 empty space which lay between the two ends of the 

 wires at the opposite ends of the tubes. The first 

 inference was, then, that an absolute vacuum would 

 be a perfect conductor of electricity. But even be- 

 fore Crookes' time it had been found that a degree 

 of exhaustion could be reached where the conduc- 

 tivity began to grow less again. Professor Crookes 

 was able to make bulbs emptied so far that it took 

 a very high electrical charge to jump a gap of even 

 moderate length. The inference from this was that 

 if the vacuum were carried still further, a bulb 

 could be made which would not conduct electricity 

 at all. A perfect vacuum would be an absolute bar. 

 If this be true, said Professor Crookes, then it 

 is not the hypothetical ether which carries these 

 "rays," but a very tenuous form of matter. He 

 pictured the particles of the tiny residue of gas in 

 the tube as becoming electrified by contact with the 

 cathode end of the electrical circuit and shot away at 

 a frightful speed by virtue of the repulsion of like 

 kinds of electricity. So he was led to sum up all these 

 curious phenomena under the name of radiant matter. 



The tea-kettle of science knows storms quite as 

 violent as those which can arise from differences of 



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