144 Experiments with High Frequency Electric Discharges. 



that with continuous and ordinary alternating currents can 

 only be obtained by the use of much larger currents. 



This hypothesis is probably applicable to many other high- 

 frequency effects, but as applied to the above-mentioned 

 experiment it is simply this : — The lamp-filament having a 

 certain definiie resistance, with continuous or ordinary alter- 

 nating currents which pass uniformly or nearly so through 

 the section of the filament, a certain amperage of current is 

 necessary to produce the number of watts required to raise 

 the filament to incandescence. With the high-frequency 

 currents, on the other hand, as is well understood, the current 

 travels chiefly on the outer surface of the filament, little or 

 none passing through the central portion. The current is in 

 fact merely skin-deep. The virtual resistance is therefore 

 very high, as only an extremely small portion of the sectional 

 area of the filament acts as a conductor. There is an ample 

 sufficiency of volts, and though the current is very minute 

 there is a sufficient expenditure of watts to raise the filament 

 to incandescence. The lamp, in fact, ceases to be a 100-volt 

 lamp and becomes, it may well be, a 100,000-volt lamp. As 

 confirming this hypothesis, it should be mentioned that while 

 the filament was incandescent, sparks passed between the lamp 

 terminals, which were at some distance apart, this being evi- 

 dence that there was a difference of potential amounting 

 at least to thousands of volts between the two ends of the 

 filament. 



Returning to the experiments, several other curious results 

 were obtained. If, instead of connecting the lamp to the coil 

 through the human frame, a wire was used, the filament 

 became much brighter than in the previous experiment ; in 

 fact, it gave considerably more than its normal candle-power. 

 From this it was evident that the human body offered con- 

 siderable opposition of some description to the passage of the 

 electricity. In order to form some idea of the amount of 

 this opposition, the body was again inserted in the circuit 

 between the coil and the lamp, as previously, and the thumbs 

 of the two hands brought near together. Sparks about one 

 quarter of an inch in length were found to pass between them, 

 evidencing that the two hands of the operator had a difference 

 of potential between them apparently equal to some thousands 

 of volts. When the sparks passed bet-ween the hands, or when 

 the wrists were brought into contact, so as to short-circuit, as 

 it were, to some extent the resistance of the arms and body, 

 the filament became very appreciably brighter. It should be 

 mentioned that when the sparks were allowed to pass be- 

 tween the hands very perceptible shocks were felt in the 

 wrists. 



