A HOME-MADE TELEPHONE.

Otago Witness, Issue 2817, 4 March 1908, Page 87

A HOME-MADE TELEPHONE.

A telephone that will carry the voice a quarter of a mile can be made without any electrical appliance by any handy boy-

. You will only need a piece of wood, two fresh beef bladders, two buttons, some tacks, aiid a length of fine copper or tinned iron wire. The boards should be 14in long, lOin wide, and £in thick.

Cut a circular hole in each, Bin across, and smooth the edges with sandpaper. Blow up tlie bladders, tie them, and leave them for a day or two to stretch, but do not let them get dry.

Now cut off tho necks and soak the bladders in warm water until they become soft and, white. Then lay them over the holes in the board, the inside on top ; tack them on temporarily, and try if they are ©Ten by pressing in the centre.

As soon as you have arranged, them evenly fasten them down by means of a leather band wide with tacks driven very closely together. <Fig. 1.) With a sharp knife trim away the edges, pass the end of a piece of wire through the the centre of the bladder, and attach it to a button. (Fig. 2.) Fix an 81b weight to the other end, and place in the sun till thoroughly dry (as in Fig. 3.) When the bladders are dry, fasten your long wire to the short wires, and the instrument is ready. If the distance over which you want to •peak is great, you must support the wire At intervals by loops hanging from trees, etc. To ring up, tap the bottom witb a pencil. 'Then speak close to the bladder in a distinct voice, and you can be heard a quarter *f a mile away.