The battery shown in Fig. 214 is contained in a vulcanite case, closed at the two ends by screw caps. The battery proper consists of alternate layers of zinc and carbon, with the alternate pairs of layers separated by a layer of wool or other absorbent material soaked in a solution of sal ammoniac. The advantages claimed for this construction are compactness, and all the advantages of a dry cell with rechargeableness of a wet cell. thus greatly lessening the cost of upkeep. The voltage and amperage can be regulated by the size (diameter) and number of disks used.

Fig. 214 - Sectional view of the voltaic battery.