How Two Boys Made Their Own Electrical Apparatus

ted. (App. 20.)

APPARATUS 6.

[Illustration: 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 × 1/2 in. They are screwed to the cross-piece, which is 4-1/2 × 1 × 7/8 in. Do not let the screws touch each other. The wires are fastened under the screw-heads.

APPARATUS 7.

[Illustration: Fig. 7.]

8. Experimental Two-fluid Cell. Fig. 7. This cell has a zinc strip, Z, and copper cylinder, C, for the "elements." The porous cup, P C, is fully described in App. 11. Z is 5 × 1 in., and should be well amalgamated (App. 20). (Study reasons for amalgamation.) A zinc rod, like that shown in Fig. 4, may be used instead of the strip. The copper cylinder, C, nearly surrounds P C, and is made from a piece of thin sheet-copper, 6 × 2 in. The narrow strip, or leader, A