HELLO! Hello! What is it you say? You can really make a telephone? What fun! How far will it work? You think it can be heard a long distance? Very good. Could we manage to construct such a one? How, pray tell us?
The answer which came back over the line we give in a more concise form, as follows:
The best way to make a simple telephone is to procure two round, medium-sized tin baking-powder boxes, and remove the bottoms with a pair of pinchers; then soak two pieces of Whatman’s drawing-paper, or any other strong paper, in a basin of water for a few moments, and when thoroughly wet take them out and place one smoothly over the end of each box. Fasten these down by winding a waxed cotton twine securely over the paper and box, and tying it tightly (Fig. 137). This done, allow the drums to become wholly dry, when they should be firm, even, and without wrinkles. Next cut away that portion of the paper which stands out, frill-like, beyond the string, and paste a narrow strip of paper around over the twine (Fig. 138). Wax a piece of string of the desired length, and with a large needle or pin carefully punch a hole in the centre of each drum; thread one end of the waxed string through one of the holes and make a large knot in the end, then cautiously pull the string until the knot rests on the inside surface of the paper. Connect the other box to the string in like manner, so that the twine will have a box fastened on each end.
The telephone is now ready for use; and if the distance is short, the line may be stretched taut from point to point. But should the space be great, supports will be needed and loops must be made of the twine and fastened at intervals on trees, corners of the houses, or any available points, with the connecting cord passed through these loops (Fig. 139), which act as supports. Keep the course of the waxed string as straight as possible, and, as far as practicable, avoid sharp angles. This style of telephone we know, from personal experience, works perfectly at the distance of fifty yards, and doubtless it will do as well when the line is stretched much farther. Be particular, in selecting the tin baking-powder boxes, to have them round and even; if they are old and battered the experiment may not prove satisfactory. We find the telephone very useful and convenient, besides affording any amount of amusement and fun; with its aid we converse with acquaintances, even though they be at a distance. The friendly little instrument carries the voice all along the slender line to the very ears of our best friend, and we can chat away as freely and almost as easily as if side by side. What a comfort to be able, when seated in your own room, to listen to the voice of some companion, living perhaps blocks away, and it is such a pleasure, too, to have questions answered immediately, which is impossible in communications made by letter. Nor is this a pleasure to be enjoyed at rare intervals, for as long as the telephone lasts it can be used at any time for a short or long talk, as one may feel inclined. The consultations, the plans, the sport, and merriment to be had with the telephone can scarcely be appreciated by one who is not the happy possessor of such an instrument.
When the weather will not permit of a walk or a visit, the telephone brings us, if not face to face, at least within speaking distance of those to whom we desire to talk.
There are many other easy methods of making telephones. They can be manufactured as described without waxing the string, or the boxes may be used unaltered, in which case the tin bottoms serve as drums, and the holes for the string are made in the centre of each by driving a small tack through. With these instruments the voice cannot be sent a great distance, but when only a short line is needed they succeed very well.
More complicated telephones are made with the drums of bladder and the line of soft, flexible wire. Though good and serviceable, they are more difficult to make and require more time and labor.
The two beef-bladders used for such a telephone must first be blown up, tied, and left about thirty hours, or until they are stretched, but not dried. When in proper condition, cut off the necks and portion of the ends, then soak them in warm water, and they will become very pliable and light in color. Having previously prepared two square pieces of board by very carefully cutting out a perfect circle in the centre of each, about as large as a medium-sized pie-pan or a tea-plate, place the bladders smoothly but not tightly over the openings, allowing the outside of the bladder to come on the bottom, and fasten it all around the circle, a little distance from the edge, with tacks so driven in that they may be easily removed.
Try the drums with your finger; if they stretch evenly they are correct, if they wrinkle, change them until they stretch perfectly smooth. Then tack a piece of firm tape securely around the edge of the circle, and cut off the bladder reaching beyond the tape. Next fasten four feet of soft, flexible wire to a large-sized gutta-percha button by threading it through the two opposite holes in the centre of the button; pass the other end of the wire through the middle of the bladder, bringing the button flat against its surface.
After attaching a weight of about seven pounds to the end of the wire, place the drum in the sun until perfectly dry. Proceed with the other in the same manner, and when both are well dried, fasten one on each end of the line and attach the drum-wires to the principal wire by loops; then stretch it firm and tight. This telephone will also need loops for supports, which should be of wire. When the instrument is carefully and properly made it will carry the voice three or four miles or more, giving every word and tone distinctly and clearly.