Toying with HighTension Currents 



At left, Prof. Thordarson 

 and his helper and operat- 

 ing expert, Mr. Lindstrom 



Below, using an umbrella to ex- 

 periment with a three to six-inch 

 spark from the safety-screen 



ELECTRICAL science has brought 

 forth so many startling discoveries 

 in the last decade or two that even 

 the average person is rather proof against 

 being astonished at anything. Ahnost 

 incredible accomplishnients of an inven- 

 tor's years of unremitting labors are 

 often dismissed with the faint praise 

 that electricity is only in its infancy. 

 Like almost all other things, however, 

 there are exhibitions of electric force 

 that tickle the public fancy without 

 con\eying au},^ idea of commercial worth. 

 A good example of this is seen in the 

 theatrical displays with high-frequency 

 currents, the beholders little realizing 

 that they arc interesting applications of 

 the same power employed in wireless 

 telegraph transmission. 



A remarkable electrical construction 

 which has excited great interest in both 

 the curious spectator and the far-seeing 

 engineer is the 1,000 kilowatt, 1,000,000- 

 volt, 60-cycle transformer, constructed 

 by the well-known electrical instrument 

 maker, Mr. C. H. Thordarson n{ 

 Chicago. Requiring two years' time in 

 construction, costing $36,000 and entail- 

 ing no end of thought and ingenuity, it 

 was primarily made to demonstrate 



certain theories on transformer con- 

 struction and to investigate the behavior 

 of electric conductors when charged 

 with extremely high \-oltagcs. 



Electric currents, when traveling at 

 very high frequency, pass almost entirely 

 u[ion the surface of the conductor. The 

 resistance of such a circuit is therefore 

 so high that unless a high voltage is 

 operating no current at all will flow. 

 Such conditions are met in stage 

 apparatus. Ordinarily the operator can 

 handle the conductors with imiiunit\', 

 the current mereh- passing through his 

 outer skin or perhaps entirely in his 

 clothing. The alternations may readily 

 be a million per second or half |th,it 

 number of "cycles" per second. In the 

 case of ordinary electric light and power 

 circuits the most common frequency is 

 60 cycles per second, some, however, 

 being as low as 25. In such cases the 

 current flows quite like the direct sort, 

 uniformly through the section of the 

 conductor, whether it be wire or person, 

 and a \oUage as low as 1,000 is likely to 

 be fatal. It is realized, therefore, that 

 in the new Thordarson apparatus there 

 is found for the first time the combina- 

 tion of the high voltage with ordinary 



248 



