J. Trowbridge—Induced currents and derived circuits. 378 
one course in preference to the other. Two galvanometers, there- 
fore, of the same resistance, one forming the shunt to the other, 
will give the same deflection, which is equal to that given by 
the undivided circuit. 
Resistances were then introduced in the circuit exterior to the 
galvanometer coils, and a shunt of 588 ohms was used. 
The fifth column shows that no effect was produced by the 
shunt until the exterior resistance was appreciable in compari- 
son with that of the galvanometer. 
The following table exhibits the effect of resistances which 
were ay ages in comparison with the galvanometer resist- 
ne e 
he same shunt of 588 ohms was used. e second 
column is calculated on the assumption that 
oe (where &' is a coefficient), is equivalent to 7, es. and 
iz 
that the laws of Kirchoff hold. The third column is obtained 
from the experimental data. The fourth and fifth columns are 
also calculated on the assumption that 7 = — = tangent of the 
deflection. Columns second and third are expressed in arbi- 
rary scale divisions. 
Exterior 
Resistances,| Calculated |Experiment-| Ratio of Ratio of 
in ohms. value, of i. |al value, of é.| intensities. | Tangents. 
1500 1242 1375 
2000 1033 1055 1°06 1°03 
2600 954 990 1°06 1°04 
3000 767 825 1°06 1:04 
3500 673 770 Td 1°05 
4000 613 660 1°05 1:03 
4500 558 649 1°05 1°07 
5000 514 550 1°04 1°03 
It will be seen by comparison that, with large resistances ex- 
terior to the galvanometer resistance and appreciable in connec- 
Sistance exterior to the galvanometer which is appreci 
Comparison with that of the galvanometer. 
M. Jour. eee Serres, Vou. V, No. 29.—May, 1873. 
