56 



Mr. Julius Frith on 



W 



Fig. 2. 

 I Intermittent contact. ' 

 E Electrometer. 

 D Alternator. 

 B Copper bath. 

 C Ammeter. 

 E, Resistance without self-induction. 



A resistance of 4 ohms was placed in series with the 

 bath, and the curve taken at the terminals of the dynamo. 



On Plate VI. are also drawn the curve for 10 amperes 

 passed through resistance, and the curve of the machine on 

 open circuit. 



Next an arc lamp was substituted for the copper bath. 

 The potential at the terminals of the lamp was kept 

 constant and equal to 40 volts. 



Fig. 3. 



