What to do

To make the key: Take one of the pieces of wood and screw down one end of one of the 4-inch-long pieces of metal strapping. Screw another wood screw directly into the wood at the other end of the block so the bent strapping (as shown) will make a connection with the screw if you push down on it. This will be your telegraph key. The key should not touch the screw unless you push down on it.

To make the battery holder: Measure the length of the two batteries placed end to end, and mark the length on

I— Measure this distance

I— Measure this distance

To make the battery holder: Measure the length of the two batteries placed end to end, and mark the length on

the second piece of wood. Screw two of the 4-inch strips of strapping to the wood at either end of the mark so the strapping will touch the connections on the bottoms or, "ends" of the batteries. Place the batteries in the holder, and put the rubber band around both pieces of metal strapping as shown above. This will keep the strapping pressed against the battery contacts.

To make the sounder: Nail one of the long iron nails into the second piece of wood with the battery holder (see diagram). Attach one end of the insulated wire to the screw on the battery holder. Wind about 100 turns of the insulated wire around the nail, and attach the other end of the wire to the screw under the telegraph key on the other piece of wood.

Tuck metal strap under head of nail

Take the 7-inch-long piece of metal strapping and screw it to the piece of wood so that you can bend it up and over the long nail with the insulated wire wound around it. When the battery is con nected, the electric current will pass through the wire coiled around the iron nail and will make the nail into an electromagnet. It will pull the piece of bent metal down onto it, making a clicking sound. Make sure the metal is bent close enough to the nail so it will connect when the battery is connected.

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strapping, close to the nail with the wire wrapped around it, so the metal

Now take the second iron nail and nail it in right next to the metal strapping, close to the nail with the wire wrapped around it, so the metal space space strapping is tucked just under the head of the nail. This nail will keep the metal strapping from pulling too far from the electromagnet. It also makes a clicking sound when the metal strapping is released by the magnet and moves upward.

Finally, take a small piece of the wire and attach it to the other screw holding down the key. Take the other end of this wire and attach it to the screw holding the other side of the battery holder onto the wood.

How to operate the telegraph:

When you push down on the telegraph key so it touches the screw, you complete the circuit, and allow electricity to flow from the batteries through the sounder's coil. As the metal strip hits the nail in the center of the coil it makes a clicking sound. When you release the key, it breaks the circuit and the metal strip hits the other nail, making a different clicking noise, and these two sounds form the dots and dashes of Morse code.

Sound from here

Sound from here

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