Code class paper

What were the specific technical issues (refering to wire + resistance) that prevented the early telegraph to be wired directly coast to coast?

What solution finally worked?
Illustrate how that works, allowing coast to coast telegraph communication.

The thicker and long the wire, the less resistance it has. This is why wires can't be extended indefinitely.
When the telegraph was created, the solution found for a long distance communication was having human relays, that stayed all day in a box in the middle of nowhere receiving and sending back messages to be delivered. At a certain point, they discovered that a human being wasn't necessary for the message to go through, because a single piece of wood attached to both the sounder and the keys was a good mecanism to type the message. 

The key is composed by wires and electromagnet for the current to go through. People finally discovered that the electromagnet emitting current could be used to trigger a switch everytime it was on.