the rest, i. e. ies onducting power is not affe ected by any ac- 
tion, either of the adjacent metal as such, or of tha current exist- 
ing in it. This was tried rudely in the following manner. Five 
brass wires, No. 26, — io 4,) having their extremities, 
in common with those of Fig. 4. 
the gauge wire abed, sol- 
dered to sheets of tin plate, 
were bound into a bundle 
from a’ to b’, and separated 
to a little didtative through the remainder of their Si The 
current being passed between A and B, and points of aaa ten- 
sion a and a’, &c. taken, the result was, 
ab =25-455 in. cd =26-080 in. 
a’b! =25-436 “ Mean “ five e’d’, ed’, &c. i 18F* 
a'b’.cd 3 ed’ .ab: 205: 
The discrepancy is cane witht the possible limits of un- 
equal conduction in the wires, and the result shows that the wires" 
in the bundle do not mutually interfere with each other’s con- 
ducting power. This accords with the result of a different ex- 
periment of Prof. Faraday, from which he concludes “that col- 
lateral currents, either in the same or in opposite directions, exert 
no permanent inducing power on each other, affecting their quan- 
tity or tension.”* The inclination of the wires between 0’ and 
e’, e”, &c. is almost exactly compensated by averaging the lengths 
of e’d’, ed”, &c. A more elegant form of experiment would be 
to compare one part of a wire extended, with the remainder in 
coil, but we should lose the condition of actual contact between 
the ‘aidjnoeitk wires. 
13. The obvious method, however, of deciding the truth of 
the proposition now under Sonatas: is to compare two solid 
conductors of different sections. Wires would not answer, on 
account of the probable difference of texture in different siZes. 
Rods of wrought metal of the same size and quality, might be 
cut and ground down to different sizes without disturbing the 
texture, taking care to remove the whole exterior portion. a 
treme uniformity of section in the conductor would be unneces- 
sary, if the true average be taken by weighing the identical part 
concerned in the experiment. But having no means to perform 
is aa eer 
* Experimental Researches, vol. i, p. 6. 
