The Samson Cell.
Fig. 53 is one of the Leclanche group, in which a compound carbon element displaces the earthenware porous cup. This carbon is composed of two parts, a hollow-fluted lower piece and a threaded top, which carries the binding post. In the process of manufacture, the top piece is heated red-hot and plunged into hot paraffin wax, thus ensuring a complete diffusion of the paraffin throughout the carbon. In this way the creeping of salt or solution, and consequent corrosion of electrodes and failure of cell, are avoided. The lower portion is much more porous than the upper and is filled with a combination of pea-carbon and peroxide of manganese held in by a plug at the bottom. This plug can be removed and new depolarizer added. Directions given by the manufacturers for renewing this element are to hold the lower end of the carbon over a burner flame until the plug is softened and can be removed, or to immerse the extreme lower end of the carbon in boiling water. After refilling, a cork plug can be used.
Fig. 53.
The E. M. F. of the No. 2 size is from 1.40 to 1.47 volts, and current, on short circuit, of 12 to 16 amperes. The No. 2 Special has same E. M. F., but current of only 5 amperes, being intended where strong current is not required but quick recuperation. It will be seen that this cell is far more suited to electric gas-lighting work than the simple Leclanche, owing to its great current delivery.