§ 31. The ordinary form of Leclanché is found in market in three sizes, viz., No. 1, No. 2, and No. 3. Unfortunately, all makers do not use these numbers in the same manner, so that while some call the smallest, or pint size, No. 1, others give this name to the largest, or three-pint, size. No. 2 is always quart size, and this is the one commonly employed. When several cells are employed to work a number of bells, it is well, in order that they may not receive injury, that they be enclosed in a wooden box. As it is necessary that the batteries should be inspected from time to time, boxes are specially made with doubled hinged top and side, so that when the catch is released these fall flat; thus admitting of easy inspection or removal of any individual cell. This form of battery box is shown at [Fig. 11].
Fig. 11. Battery in Box.
§ 32. There are certain ills to which the Leclanché cells are liable that require notice here. The first is creeping. By creeping is meant the gradual crystallisation of the sal ammonium up the inside and round the outside of the glass containing jar. There are two modes of preventing this. The first consists in filling in the neck with melted pitch, two small funnel-like tubes being previously inserted to admit of the addition of fresh sal ammoniac solution, and for the escape of gas. This mode cannot be recommended, as it is almost impossible to remove the pitch (in case it be required to renew the zinc, etc.) without breaking the glass vessel. The best way to remove the pitch is to
place the cell in a large saucepan of cold water, and set it on a fire until the water boils. The pitch is, by this treatment, so far softened that the elements can be removed and the pitch scraped away with a knife.
Fig. 12.