Torpedoes and Torpedo Warfare / Containing a Complete and Concise Account of the Rise and Progress of Submarine Warfare

by Charles William Sleeman

The resistance of the battery or the internal resistance depends on the size of the plates and the distance between them, that is, it is directly proportional to the distance, and inversely proportional to the size.

The electro-motive force of a battery is dependent generally on the number of cells joined in series, and not on the size of the plates. The cells of a battery may be joined in two ways, as follows:—

1. In series: that is, by connecting the negative element of one cell to the positive element of another, and so on.

2. In multiple arc: that is, by connecting negative to negative, and positive to positive; which is the same as increasing the size of the cells.

If the conductor between the battery poles be such that the external resistance x may be practically left out, then C = E / r, and no change in the strength of the current will be effected by adding any number of cells in series, as r will increase equally with E, and therefore C will remain the same; but if under the same conditions the cells be joined in multiple arc, then r will decrease as E increases, and therefore C will be increased.

Thus with a short circuit of small external resistance, the strength of the current will be increased by increasing the size of the plates, or by joining the cells in multiple arc, but not in series.

If the conductor between the poles of the battery be such that the external resistance x becomes very great, then C = E / (x + r), where x is very great compared to r. By joining the cells in multiple arc r is decreased, but E and x remain the same, and therefore C is not materially altered, as x is very great compared to r. By connecting the cell in series, r is increased, and so is E, but as r is still very small compared to x, the strength of the current C is increased.

Thus with a long circuit of great external resistance, the strength of the current will be increased by joining the cells in series, but not in multiple arc.

When the external resistance x is neither very large nor very small in comparison with the battery or internal resistance r, then the strength of the current C will be increased by adding the cells in series, and also in multiple arc. By the former process the E.M.F. E is increased more than the resistance of the circuit R or (x + r), and by the latter process, the E.M.F. E is unaltered, whilst the circuit resistance (x + r) is decreased. All the above may be practically demonstrated by the employment of suitable galvanometers.