The Negative Plate.—The negative plate is[p. 85] filled, in like manner, with precipitated lead. This lead is made by putting a strip of zinc into a standard solution of acetate of lead, and crystals will then form on the zinc. These will be very thin, and will adhere together, firmly, forming a porous mass. This, when saturated and kept under water for a short time, may be put into the openings of the negative plate.
Connecting Up the Plates.—The next step is to put these plates in position to form a battery. In Fig. [63] is shown a collection of plates connected together
For simplicity in illustrating, the cell is made up of glass, porcelain, or hard rubber, with five plates (A), A, A representing the negative and B, B the positive plates. A base of grooved strips (C, C) is placed in the batteries of the cell to receive the lower ends of the plates. The positive plates are held apart by means of a short section of tubing (D), which is clamped and held within the plates by a bolt (E), this bolt also being designed to hold the terminal strip (F).
In like manner, the negative plates are held apart by the two tubular sections (G), each of which is of the same length as the section D of the positives. The bolt (H) holds the negatives together as well as the terminal (I). The terminals should be lead strips, and it would be well, owing to the acid fumes which are formed, to coat all brass work, screws, etc., with paraffine wax.
The electrolyte or acid used in the cell, for working purposes, is a pure sulphuric acid, which should be diluted with about four times its weight in water. Remember, you should always add the strong acid to the water, and never pour the water into the acid, as the latter method causes a dangerous ebullition, and does not produce a good mixture
Put enough of this solution into the cell to cover the tops of the plates, and the cell is ready.