Oscillations in the Discharge of a Ley den-jar. 101 



A very small percentage of this damping is to be attributed 

 to the resistance of the leads, for if R = resistance of the leads 

 for an alternating current of frequency 10 6 per second, then 

 the damping due to this resistance is given by 



_2L T 



= V2^ R °' 



Now R = \ / ^pulRn. where Z = length of wire in the 



circuit, and R its resistance for direct currents. The circuit 

 measured 125 cms. by 145 cms., therefore 7=540 cms. and 

 diameter of wire = '7 mm. 

 Then 



U = \/l X2 ' 



'58 ohm. 



540x1640 _1_ 

 7rx(-035) 2 X 10* 



•58 1 1 



Then the damping due to R = e 2x104 x axioe x 10-9 



= '985 approximately, 



which is a small damping. The damping in all the cases 

 investigated is quite large compared with this, so that the 

 expenditure of energy to which the damping is due must 

 take place in the spark-gap. The dissipation of energy due 

 to the excitation of electrical waves is very small in a leyden- 

 jar circuit, and may be neglected. 



The ohmic resistance corresponding to the absorption of 

 energy by the spark-gap was deduced by inserting in the 

 circuit a known electrolytic resistance. If R is the resistance 

 of the air-break and leads, then since 



_ R T 



72/71 = e 2L 2 =P\ say, 



then \o<rp 1 = — - 



R T 

 2L'2 ; 



and if R + r is the total resistance when the known resistance, 

 consisting in the present instance of a solution of zinc 

 sulphate with zinc electrodes, is inserted, the damping will 

 be given by R+r t 



p 2 =e 2L " 2 



and logp 2 =_-^._ ; 



then Iogp 2= R+, 



log Pi -R 



