The old man’s teeth chattered.  Detroit Jim’s thin fingers tugged at his sleeve.  That meant getting busy, and digging with the pick with the sawed-off handle.  So Anderson wriggled into the horizontal chamber, which was just large enough to permit his body and arms to function.

As he hacked away at the damp earth, he could see in the pitch darkness the dirty sheet of paper, now in Detroit Jim’s pocket, upon which their very life depended.  It was a tracing made by a discharged convict from a dusty leather-covered book in the public library in New York, sent in by the underground to Jim.  The book had contained the report of some forgotten architect, back in the fifties of the last century, and the diagram in his report showed the water and sewage conduit—­in use!  It ran from the prison building, right down across the yard, six feet under ground, and out under the north wall, under the street outside, and finally into the river.  Built of brick, four feet wide, four feet high.  A ready-made tunnel to freedom!

Old Man Anderson could hear Detroit Jim’s hoarse whisper now, as he chopped away at the dirt, which he shoved back under his stomach, to where Jim’s fingers caught it and thrust it farther back.

“We’re only a couple of feet from that old conduit right now.  Dig, you son of a gun, dig!  Can the snifflin’!  You dig, and then I’ll dig!”

They were saving their matches and candles against necessity.  Mechanically the old man chopped and hacked at the wall of earth in front of him.  Now and then the pick would encounter a stone or some other hard substance.  In the last few days they had come upon frequent pieces of old brick.  Detroit Jim had rejoiced over these signs.  For the old man every falling clod of earth seemed to bring him nearer to freedom.  They also took his mind off Slattery.

So he chopped away, how long he did not know.  Suddenly his pick struck an obstacle again.  He hacked at it.  It gave slightly.  A third time he struck it, and it seemed to recede.  An odour of mouldy air filled his nostrils.  In that little aperture his pick touched nothing now!  He heard something fall!  Then he knew!  There was a hollow place in front of them!  The abandoned conduit?  He stifled a shout.

From somewhere, muffled at first, but ultimately faintly strident, rose a prolonged wail that seemed to issue from the very earth.  The sound rose, and fell, and rose again.  Frantically the pick of Old Man Anderson hacked away at the dirt, and then at whatever was in front of him.  Detroit Jim snapped the feeble flashlight then.  It was a wall—­the conduit wall!

Meantime, the prison siren shrieked out to the countryside the news of an escape.

What time it was—­whether night or day or what day, neither Jim nor Old Man Anderson knew.  They had slept, of course, and Jim had forgotten to wind his watch.  Had one week or two weeks passed?  If two weeks had slipped by and if the prison officers ran true to form they would by now have ceased searching inside the prison walls.