Leclanché Cell

—An open circuit cell used to a great extent in telephone work and with electric bells; it has a negative electrode consisting of carbon and peroxide of. manganese, a positive electrode of zinc, and an electrolyte composed of a solution of sal ammoniac. This cell polarizes quickly, but on open circuit it slowly recovers its working condition. In the operation of the cell the chemical reaction which takes place is as follows: The zine becomes oxidized by the oxygen from the manganese peroxide, and is subsequently converted into zine chloride by the action of the sal ammoniac. After the battery has been in continuous use for some hours, the manganese becomes exhausted of oxygen, and the force of the electrical current is greatly diminished; but if the battery be allowed to rest for a short time, the manganese obtains a fresh supply of oxygen from the atmosphere, and is again fit for use. After about 18 months’ work, the gla cell will probably require recharging with sal ammoniac, and the zine rod may also need renewing; but should the porous cell get out of order, it is better to get a new one than to attempt to recharge it.