The careful insulation of the trough and all parts of the apparatus, and the purity of the metal and its amalgamation, reduce the local attack of the zinc to almost nothing. So the coefficient of restitution is now comparable with that of accumulators of the Planté type.
The following are the principal numerical data of the new zinc accumulator.
| PHYSICAL DATA. | ||
|---|---|---|
| E. | Electromotive force. | 2.36 volts. |
| R. | Mean resistance. | 0.02 ohm. |
| I. | Normal intensity of the discharge current. | 25 amperes. |
| i. | Intensity of the charge current. | 5 to 10 amperes. |
| Q. | Capacity of accumulation after 200 hours'formation. | 550,000 couples. |
| DATA CONCERNING CONSTRUCTION. | ||
|---|---|---|
| Efficient surface of the 4 positiveelectrodes. | 200 square dec. | |
| Efficient surface of the 3 negativeelectrodes. | 15 square dec. | |
| Weight of the positive electrodes. | 8.2 kilogrammes. | |
| Weight of the negative electrodes. | 1.4 kilogrammes. | |
| Weight of the trough. | 2.7 kilogrammes. | |
| Weight of the liquid. | 4.4 kilogrammes. | |
| Weight of the attachments. | 0.46 kilogrammes. | |
| Weight, total. | 17.16 kilogrammes. | |
The total electric work stored up is 130,000 kilogrammeters, or 7,600 kilogrammeters per kilogramme of accumulator. Theory indicates that a zinc accumulator might store up as much as 15,600 kilogrammeters per kilogramme. If the present model gives half less, it is because I have purposely exaggerated the solidity of the trough and the mass of the electrodes.
It should be remarked that this capacity of 7,600 kilogrammeters per kilogramme is much greater than that of any other accumulator constructed in France. The new model possesses, then, despite the size of the positives and the box, a relative lightness that will permit it to take a place upon electric locomotives as well as in fixed installations.
Independently of their use as accumulators, secondary zinc batteries may be utilized as regulating voltameters in lighting by incandescence, for deadening piston strokes, attenuating the irregularities in speed, and covering accidental stoppages.—E. Reynier, in La Nature.