As they realized this, despair overtook all three of them for a time. For a long period they sat, gloomily, in the darkness, without speaking. Then, all at once, reaching out his hand, MacPherson touched an iron pipe. He informed the others of his discovery and the miner declared that the metal tube led to the surface and was used to convey water to the depths of the mine. This suggested an idea to MacPherson. He picked up a bit of rock and began tapping at the pipe. He had some knowledge of telegraphy, and the taps he gave spelled out the message:
"Three of us are imprisoned. Send help."
After a time he succeeded in teaching the message to the others, and they took turns in tapping it out. But no reply came, and in despair they gave up their efforts for a time.
But MacPherson was not prepared to lose hope as easily as the others. He persisted in his tapping, hour after hour, till the rock he was tapping with cut his hands and they were bruised and sore. He was just about to give over his efforts to attract attention when there came a sudden sound that made his pulses jump.
Somebody was tapping an answer from above. MacPherson listened and made out the message.
"Where are you?"
"What do you call this tunnel?" he asked of the miner.
"Tunnel No. 4 of the Old Mine," was the reply in a listless tone. "Why?"
"Why? Because I've just got an answer to my message. There is a chance we may be saved."
The reply electrified the despairing men into new hope. They listened eagerly while MacPherson tapped out a return message.