Explosive Effect of Electrical Discharges'. 



285 



Figr. 4. 



number of the discharges of the condenser in one second could 

 be estimated. With small resistance between the battery 

 and the plates of the condenser the number of discharges 

 in a second was very great. This number decreased as the 

 resistance increased ; and was approxi- 

 mately inversely proportional to this 

 resistance. The condensers were of 

 glass, and of rubber, and an air-con- 

 denser was also employed. In every 

 case the number of discharges was 

 inversely proportional to the resistance 

 between one plate of the condenser 

 and the battery. 



Since the frequency of the dis- 

 charge of the condenser depended upon 

 the resistance between one plate of 

 the condenser and the battery, it was 

 evident that the energy of the battery 

 was employed to charge the conden- 

 ser to a sufficient surface density to 

 enable a spark to be formed. A portion of this energy 

 was wasted in a silent discharge from the coatings and 

 terminals of the condenser. This silent discharge can be 

 regarded as a species of ionization. The condenser with its 

 terminals forms a species of voltaic cell with a phenomenon of 

 polarization. If the capacity of the condenser was increased, 

 the effect was the same as that produced by increasing the 

 resistance, as far as diminishing the number of discharges in 

 a second. The energy of each discharge in this case was not 

 similarly diminished, since the entire strength of the battery 

 served to charge the condensers. 



In the phenomenon of the explosion produced by electrical 

 discharges we are therefore dealing with electrostatic effects 

 rather than with heat phenomena ; and very high potentials 

 bring to light in a marked way the phenomena of the electro- 

 static field. With differences of potential above one million 

 volts ordinary air becomes a fairly good conductor. The 

 electric force diminishes much more rapidly with the distance 

 than the magnetic force (shown by Hertz). Phenomena of 

 light are produced in the electrostatic field : and there are 

 movements of molecules which may be embraced under the 

 broad term ionization. We are therefore led to the following- 

 conclusions : — 



1. The explosive effect of electrical discharges is due to an 

 electrostatic effect rather than to a heat effect. 



2. A strong analogy exists between the terminal conditions 



