THE PEESSURE UPON THE POLES OF THE ELECTRIC ARC. 



113 



Table II., they indicate the nature of the agreement between different readings ; 

 when two arcs were used the readings became much more difficult. 



TABLE II. Deflexions. Subsidiary Carbon in Centre. 8 Amperes, Alternating 



Current. 



Method 4.- The arrangement was as shown in fig. 5. Carbon rods were fixed 

 axially to the ends of the swinging copper rod, and between these and the sides of 

 two vertical carbons arcs were started. Various dispositions, shown in the same 

 figure, were used, which gave couples which were simple multiples of that due to the 



Fig. 5. 



pressure upon the pole acting at the end of the swinging arm. For example, 

 for disposition g the couple is twice that given by disposition d. Save for the 

 small element of current in the arc itself the electromagnetic effects should be 

 eliminated. 



