Fig. 5.
6. Experimental Cell. Fig. 5. Cut a strip each of copper, C, and zinc, Z. (See list of materials.) They should be about 2 in. wide and 4 in. long. Punch a hole through each, one side of the center, for screws, E. The wooden cross-piece, A, should be 4½ × 1 × ⅞ in. The battery-plates, or elements, should be screwed to this, taking care that the screws, E, do not touch each other. If the holes are made in the position shown in Fig. 5, the screws can be arranged some distance apart.
The wires leading from the cell may be fastened under the screws with copper burs, or spring binding-posts ([App. 42]) can be slipped on the top of the plates.
The solution to be used will depend upon what the cell is to do. For simple experiments use the dilute acid ([App. 14]). If for small motors, use the formula given in [App. 15]. The zinc should be well amalgamated. ([App. 20].)
Fig. 6.
7. Experimental Cell. Fig. 6. In some experiments a comparison is made between cells with large plates and cells with small ones. This form will be convenient to use where narrow plates are desired. Those shown are 4 × ½ in. They are screwed to the cross-piece, which is 4½ × 1 × ⅞ in. Do not let the screws touch each other. The wires are fastened under the screw-heads.