id the boy at last; and as Gwyn made one effort
to summon his courage, and dashed through the door, he followed.

The noise was now almost deafening, and at a glance they saw that the
steam was escaping furiously from the two long boilers at the end
farthest from where they stood, but the new bright engine, with its
cylinders, pistons, rods, cranks, driving-wheel, governor, and
eccentric, seemed to be perfectly safe.

"He has been in and driven a pickaxe into each of the boilers," cried
Joe. "They'll blow up together. Shall we run?"

The boy's words were almost drowned by the fierce hissing, which was now
mingled with a deep bass formed by a loud humming, throbbing sound such
as might be made by a Brobdingnagian tea-kettle, just upon ready for
use. Then came loud cracking and spitting sounds, and the dull roar of
big fires.

But the man of whom they were in search was invisible, and Gwyn walked
quickly round to the other side of the engine and looked sharply down
that side of the long building.

Joe followed.

It was darker here, and the steam which filled the open roof, and was
passing out of a louvre, hung lower, so that the far end was seen
through a mist. "Not here," said Gwyn. "Think we could stop the steam
escaping?"

"Don't know," shouted back Joe. "Sha'n't we be scalded to death?"

"Let's go and try."

That was enough for Joe, who felt as if he would have given anything for
the power to rush out, but seemed held there by his companion's example.

"Go on, then," he panted out; and Gwyn had taken a couple of steps into
the hot vapour, his heart throbbing violently with the great dread of
ignorance, when, beyond the mist which was looking light in front of the
door at the far end, there was a heavy, quick step. They could see a
dark, shadowy figure, which looked of gigantic proportions through the
hanging steam, and heard the crackling and crushing of coal under its
feet, as it descended the stone steps into the stoke hole. This was
followed by the rattling of an iron bar, quickly used, the rattle and
clang of an iron door being thrown open, when a sudden glare of
brilliant light turned the cloud of steam from grey to ruddy gold.

"Hullo! there," shouted a voice, evidently from the door by which the
boys had entered; and in an instant there was a rush of feet, the
crackling of the coal on the granite steps, and they saw the dark shadow
once more, as it darted out through the far door.

At the