3874 F. H. Bigelow—Method of measuring induced currents. 
No. V.—On a method of measuring induced currents ; by F. H. 
Ifa Wheatstone’s bridge be formed, in which the secondary 
cou of the inductorium is the resistance R' to be measured, the 
seen by the paper of Mr. Trowbridge accompanying this, tnis 
method is especially advantageous. en the bridge was set 
up so that the smallest variation in the resistance of the branch 
containing the inductorium gave the greatest variation 1 
the current going through the galvanometer, namely, when 
0 
ae O, S, being the current through the galvanometer, and 
the resulting value of R, being Bee fee Ry) in which 
G is the resistance of the galvanometer, B that of the cireult 
exterior to the Wheatstone’s bridge, it was found that the in- 
duced currents could be measured to one hundred-thousand 
of an ohm. 
The following table contains a comparison of the induced 
currents produced by making and breaking the circuit. The 
first two columns contain the variation in ohms of the variable 
resistance of the bridge; the third and fourth columns give the 
strength of the induced currents on making and breaking 
expressed in ohms, 
