One edge and one end only of the bottom should now be planed square, the other edge and end being left to plane after the bottom is nailed in place. Cut a piece of tin 1/16" smaller than the glass, or glue some tinfoil on the inside of the bottom. If tinfoil is to be used, smooth it on a piece of paper carefully with the fingers; then spread some glue thinly over the bottom, and lay the tinfoil on it. The squared edge and end of the bottom are to be nailed first, having them fit nicely; then the other edge and end. Never drive a nail too near the corner of the bottom lest it strike the nails driven thru the sides of the box. Now plane the end and then the side of the bottom to fit. If tin is used instead of tinfoil put it inside the box after the bottom has been nailed in place. Make the two supports fit inside the box lengthwise and just wide enough to hold the top of the glass flush with the top edges of the box. To hold the supports, drive nails thru the ends of the box into them.
MAGIC BOX AND PENCIL BOX — Plate 10
Everything about electrical apparatus should be clean and dry, so, as this is really an electric box, have the glass and tin clean before using it. Put some bits of charcoal, paper, straw, or sawdust into the box, have it warm and dry, rub the glass with a piece of leather (glove, shoe), and then see how the little people jump! The explanation is as follows: Rubbing glass with leather, fur, woolen, or silk generates electricity; this electricity attracts non-electrified bodies, thus lifting the little people to the glass; as soon as they become charged with the electricity on the glass, they are repelled and thrown down to the tin; the tin conducts their charge of electricity away, and they are ready to begin their circus over again.
[PENCIL-BOX—][Plate 10].
To make this box, saw out one long piece for the sides and ends, 22" × 1-7/8" × 1/4", or two shorter pieces, 12" × 1-7/8" × 1/4". The reason for having them so long is because it is difficult to make the groove nicely to the end of the board; and they are wide enough to try twice to make the groove.