The explosion had, as Jack well knew, destroyed all the doors which direct the currents of the air, and the ventilation had entirely ceased. The lower part of the mine, where the explosion had been strongest, would soon be filled with choke-damp, and Jack was making for the old workings, near the upper boundary line of the pit. There the air would remain pure long after it had become poisonous elsewhere.
It was in this quarter of the mine that Bill Haden (Jack's adopted father) and some twenty other colliers worked.
Presently Jack saw lights ahead, and heard a clattering of steps. It was clear that, as he had hoped, the miners working there had escaped the force of the explosion, which had, without doubt, played awful havoc in the parts of the mine where the greater part of the men were at work.
"Stop! stop!" Jack shouted, as they came up to him.
"Is it fire, Jack?" Bill Haden, who was one of the first, asked.
"Yes, Bill; didn't you feel it?"
"Some of us thought we felt a suck of air a quarter hour since, but we weren't sure; and then came another, which blew out the lights. Come along, lad; there is no time for talking."
"It's of no use going on," Jack said; "the shaft's choked up. I came down after the first blow, and I fear there's no living soul in the new workings. By this time they must be full of the choke-damp."
The men looked at each other with blank faces.
"Have you seen Brook?" Jack asked eagerly.