496 THE INTELLECTUAL RISE IN ELECTRICITY. 



tenberg and an Imperial Count Palatine, so that his for- 

 tunes had evidently improved. He was now certainly 

 producing the most powerful electrical discharges that had 

 ever been seen, and popular excitement (and his own) con- 

 cerning them was rapidly increasing. His constant desire 

 was stronger effects, and with this object he sacrificed a 

 large telescope in order to obtain its metal tube, some 

 twenty-one feet in length. When he brought this close to 

 his revolving globe the.sparks leaped to it in great profu- 

 sion, and finally, when it barely touched the glass, a ring 

 of intense light appeared at the place of contact, while the 

 discharge from the tube itself was powerful enough to 

 knock a dollar from between his teeth, and cause a wound 

 whenever it was allowed to strike the exposed skin. 



He had now added to the electric machine, for the first 

 time, the prime conductor. The tube was first held to the 

 globe by hand, but afterwards suspended by silk cords. It 

 collected the charge from the excited glass by a number 

 of threads resting upon the revolving surface, performing 

 the same functions as the numerous points of the collect- 

 ing comb in the modern frictional machine. 



It will be remembered that one of the discoveries which 

 Dufay believed possible and desired to make, but in which 

 he failed, as he conceived, because of the omission of some 

 necessary precaution, was the proof of the identity of the 

 electric spark with actual fire. Bose, in 1743, had reached 

 sufficient faith in this to suggest the question anew, but 

 then announced no proof. In January of 1744 the reor- 

 ganized Academy of Sciences was formally opened in Ber- 

 lin before an assembly of all the notabilities of the king- 

 dom, and an address on electricity was delivered by Dr. 

 Christian Friedrich L,udolff, in the course of which he 

 exhibited the attractive effect of a rubbed glass tube upon 

 water, and the apparent projection of the sparks from the 

 tube to the liquid. While performing this experiment it 

 occurred to him to substitute for the water some highly 

 inflammable fluid, and see what effect the sparks flash- 



