File a nail (about 3/32" in diameter) sharp like a chisel, and drive it tightly into a small hole, drilled in a block of wood which has one corner rabbeted, that is, sawed away as shown in [Fig. 3]. The outside of the nail, measured from the shoulder of the rabbet, must be exactly 1/4" away, so that the lower edge of the groove will be 1/4" from the top of the box. Practice with this tool till a good groove can be made in waste lumber, then make the groove along one edge of the board. When well done, plane the board 1-3/8" wide, and saw it to the proper lengths for sides and ends. In the front end there is no groove, so plane it away from one piece just sawed. Sandpaper the flat sides before gluing and nailing them together. Prepare the bottom as directed for the magic box, [page 38], then sandpaper, glue and nail it in place. Set all nails. Plane the bottom to fit. Prepare the cover somewhat too long but exactly the width between the grooves. As in making the whistle, [page 32], so here draw pencil lines for the bevel 3/8" wide on the cover. Practice planing a bevel on waste wood first. The bevel at the further end of the cover can be planed by holding the cover upright in the vise. When it slides smoothly in the grooves, saw it the right length. For the notch, make a deep cut with a gouge, and cut the chip straight across with knife point or small chisel. Hold it in the bench-hook while doing this.
Fig. 3
[TELEPHONE—][Plate 11].
In these days when even boys are using wireless telegraphy, this may seem a humble telephone, but it is a surprisingly good one, and it is very easily made and operated. The drum should be hard and tight, the string should be a small, hard cord (tho the common pink cord thoroly waxed with paraffin will do), and the cord should be supported by nothing but the drums when the telephone is being used.
After preparing the eight sides, observe in [Plate 11], the method of nailing four boards of equal width together to form a square,—each one is nailed to another one. The ends of the boxes should be well rounded with sandpaper before the drum is stretched over them.
The best material for the drum is rawhide,—the dried skin of an animal. The skin of a small animal like the cat, rabbit, or woodchuck is best. Country boys will not have much difficulty in securing such rawhide, but city boys may. To remove the hair, or fur, from a skin, slack a lump of lime as large as a hen's egg in a basin of water and soak the skin in it until the hair can be pulled off readily (usually a few minutes); then thoroly wash the skin, stretch it over one end of a box, and tack it every 3/8" with 2 oz. tacks. When thoroly dry it will be "tight as a drum" and ready to use. A good drum can also be made of an old (dressed) kid glove or shoe. Soak a piece 4" sq. in water a few minutes then stretch it while still wet, tightly over the box. When dry, coat it on both sides with melted paraffin. Fasten the cord to the drum simply by a knot on the inside. If common pink cord is used, drive the paraffin in with a hot flat-iron.
To use the telephone, a boy at each end of the line holds his box so that the string will not touch anything, then one talks into his box while the other listens in his. The telephone may be stretched from one house to another if the houses are within several hundred feet of each other and have a free space between. If two telephones were provided, a person could talk and listen at the same time.