Quick as lightning an answer rang back as if by magic, along the
conducting line of the rail--a strange unexpected answer.

"Break the pipe of the wires," it said, and then subsided instantly.

Cyril, who was leaning down at her side at the moment with his ear
to the rail, couldn't make out one word of it. But Elma's sharp
senses, now quickened by the crisis, were acute as an Oriental's
and keen as a beagle's.

"Break the pipe of the wires," they say, she exclaimed, starting
back and pondering. "What on earth can they mean by that? What
on earth can they be driving at? 'Break the pipe of the wires.' I
don't understand them."

Hardly had she spoken, when another sharp tap resounded still more
clearly along the rail at her feet. She bent down her head once
more, and laid her eager ear beside it in terrible suspense. A rough
man's voice--a navvy's, no doubt, or a fireman's--came speeding
along the metal; and it said in thick accents--

"Do you hear what I say? If you want to breathe freer, break the
pipe of the wires, and you'll get fresh air from outside right
through it."

Cyril this time had caught the words, and jumped up with a sudden
air of profound conviction. It was very dark, and the lamps were
going out, but he took his fusee-box from his pocket and struck a
light hastily. Sure enough, on the left-hand side of the tunnel,
half buried in rubbish, an earthenware pipe ran along by the edge