THE PEESSURE UPON THE POLES OF THE ELECTRIC ARC. 
I 13 
Table IT., they indicate the nature of the agreement between different I'eadings ; 
when two arcs were used the readings became much more difficult. 
Table II.—Deflexions. Subsidiary Carbon in Centre. 8 Amperes, Alternating 
Current. 
Zero. 
B. 
A. 
B. 
A. 
B-A. 
Total 
pressure in 
dynes. 
29°-5 
-5°-0 
23°-5 
-3°-5 
' 
23°-0 
27°-.5 
0-76 
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 
% i % ^ ^ 9 ^ ^ 
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9 
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. 
