shut off the current. When through playing with the truck, however, it is important to remove both pairs of elements and wash them off, because the bi-chromate solution attacks the zinc elements even when the current is not in use. As the bi-chromate solution stains very badly, it is advisable to operate the motor truck only where there is no danger of ruining anything in case some of the solution spills, as in the basement or workshop. If you wish to use a dry-cell instead of the pair of bi-chromate cells, you can place the cell upon the floor and make the wires connecting it to the motor long enough so the truck can run back and forth across a room.
The Seat and Canopy-Top details are shown in Fig. 210. Make these in about the proportion to the cigar-box shown in Fig. 199. Fasten the seat to the edge of the seat-back B with glue and brads, and then fasten the side pieces A to the ends of the seat. The dashboard E is nailed to the
Fig. 210.—Details of Seat and Canopy-Top.
