Then, taking the little packet, he dropped it.  Mike put on his hat again, turned round, then looked cautiously to see that no one was noticing him, and strolled, in an aimless and leisurely way, towards the wall.  Desmond could no longer see him, but felt sure that he would find the missive.

Presently he came in sight again, walking quietly away.  He did not look round; but when nearly at the bottom of the hill turned, lifted one hand, and disappeared behind some houses.

“He can’t read,” Desmond said, “but I have no doubt he will get someone to do it for him.”

A vigilant watch was kept up, but nothing was seen of Mike, till late in the afternoon, when he emerged into one of the open spaces.  They had now taken the handkerchief down from the window, and, directly they saw him, Desmond waved it, showing that they were watching him.  He threw up his arm, turned, and disappeared again.

“He has made out my message,” Desmond said.  “We may expect him here at ten o’clock.”

While he had been watching, his two comrades had, under his instructions, been unravelling a portion of one of their blankets.  When enough thread had been obtained, the strands were tied together and doubled, and Desmond had little doubt that it was sufficiently strong to draw up the string Mike would bring with him.  He now took another portion of the bill, and pricked upon it the words: 

At nine tomorrow night, bring, if possible, fine steel saw, two files, and small bottle of oil.  Fasten these to string we will lower with further instructions.

He then opened his coatee, took out some of the white wool with which it was padded, formed this into a loose ball, in the centre of which the note was fastened, and all being in readiness, waited patiently, until, just as the city clock struck ten, they heard a low whistle.  The ball had already been attached to the end of the thread, and Desmond at once lowered it down.

Presently, they heard another whistle and, hauling at it again, they found that the ball had gone, and attached to the end of the thread was a very light silken cord, which they drew in.  There was another low whistle, and all was silent.

“So far, so good,” Desmond said.  “We are fairly on our way to liberty.  How long do you suppose it will take us to cut through these bars?”

“It would take us a long while to file through them all,” O’Neil said, “but with a fine steel saw, I should think that a couple of nights’ work should do it.  But of course that is mere guesswork, for I have not the least idea how fast even the best saw could cut through iron.”

“Well, there is no particular hurry, for we know that no day has been fixed yet for our trial.  So, whether it is one night or six, it does not matter much.”

On the following evening at nine o’clock the whistle was heard, and another ball lowered down at the end of the string.  The instructions this time were: