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XXVII. Experiments with High Frequency Discharges. 

 By Mr. A. A. C. Swinton*. 



EMPLOYING the apparatus, described in the Philosophical 

 Magazine for February 1893, pages 142-143, for pro- 

 ducing electric discharges of high potential and high frequency, 

 the writer has obtained several curious effects. 



A flat tin dish filled to a depth of about half an inch with 

 resin oil was electrically connected to one terminal of the 

 high-frequency coil, and a wire connected to the other 

 terminal of the coil was suspended with its extremity about 

 three or four inches above the surface of the oil in the dish. 



On putting the coil in action the oil was immediately thrown 

 into a state of violent agitation, the whole surface bubbling 

 and foaming, while the oil gradually crept up the inclined 

 sides of the dish in a well-defined wave and, finally, overflowed. 



The effect appears to be due in great measure to the violent 

 repulsion of the particles of air from the suspended wire into 

 the oil. 



A similar result was obtained when alcohol was substituted 

 for oil in the dish, but the alcohol immediately caught fire. 



With ordinary paraffin oil the effect was the same and the 

 oil caught fire, but only continued to burn so long as the 

 electric discharge, which supplied the additional heat necessary 

 to keep the oil burning, was maintained. 



Distilled water was next tried, but with this no agitation 

 of the surface or creeping up of the liquid ensued. 



When, however, the suspended wire was lowered so as to 

 touch the surface of the water, an octopus-like figure of 

 bright sparks, about two to three inches in diameter, was 

 formed on the surface of the water, and even when the wire 

 was further lowered so as to dip three eighths of an inch into 

 the water, so that the point of the wire was within one eighth 

 of an inch of the tin dish, the sparks still spread out, leaving 

 the wire at its intersection with the surface of the water, and 

 not at the point of the wire, which, as already mentioned, was 

 within one eighth of an inch of the tin dish. 



In fact, it was not until the point of the wire and the dish 

 were brought very nearly into contact that the discharge took 

 place through the water, which it then did with very white 

 sparks producing small explosions, and the sparks on the 

 surface ceased. 



As instancing the strong electrostatic effects produced 



* Communicated by the Author. 



