Swinging his half-conscious companion round, he propped him against the wall. Then, freeing one hand, he dragged out the clasp-knife which he always carried in his pocket, and wrenched open the blade with his teeth.
As he did so, Colin by great effort managed to force a few words from between his chattering teeth.
"There's another on—round my feet. Cut that too if you can."
"Right you are!" shouted Joe encouragingly. "Keep it up, doctor, and I'll 'ave you loose in a couple o' shakes."
With feverish haste he accomplished the first part of his task, and then, taking a deep breath, plunged his way down through the water until his fingers encountered the second cord. One vicious slash severed the wet strand, and, uncoiling it as rapidly as he could, he struggled back to the surface, puffing and gasping for air.
Quick as he had been, there was scarcely a second to spare. The water was already up to his chin, and Colin, although his legs and arms were now free, was far too numbed and exhausted to make more than the feeblest efforts on his own behalf.
Summoning every ounce of his strength, Joe lifted the latter bodily in his arms. Then with swaying steps he stumbled forward in the direction of the trapdoor, where the little yellow flame of the candle which Nancy was holding flickered and gleamed above their heads.
"Get 'old of the ladder, guv'nor," he panted. "Get 'old of it some'ow and I'll shove yer up."
Colin heard, and with blue and stiffened fingers caught desperately at the rungs.
At the same moment he glanced up toward the trap, and there, sharply illuminated in the candle-light, he saw Nancy's face bending down toward him.