hero of the measuring and another
sour-looking fellow were making their way round to where the two boilers
were beginning to be charged with steam, and what was worse for all
concerned, no one paid any heed to their movements, which were furtive
and strange, suggesting that they had not come for the purpose of doing
good, while their opportunities for doing a serious ill were ample; but
Gwyn had just grasped that fact.

CHAPTER FIFTEEN.

IN THE ENGINE-HOUSE.

The boys hardly spoke as they made their way towards the engine-house,
from whence came a loud hissing noise, and on hearing this, Joe
exclaimed excitedly,--

"He's there."

For answer Gwyn ran to the door, and entered, hardly knowing what he was
about to do, but with the feeling that this man was a natural enemy,
whom it was his duty to attack; and, like a true comrade, Joe followed
closely at his heels.

The hissing noise increased as they approached the door; and, fully
alive as he was to the danger of meddling with steam, Gwyn's heart began
to beat a little faster, for he felt that they were too late; that the
mischief had been done, the steam was escaping, and that if they entered
the house, it might be at the expense of a terrible scalding.

All else was silent, and as they reached the doorway of the place, the
shrill, shrieking noise was piercing, and made their words difficult to
hear.

"He has broken something, or turned on the steam, so that it may escape,
Joe," said Gwyn. "Shall we go in and try to put it right?"

"If we must. But where's the engine-driver?--where's the stoker?"

Gwyn looked round, to see that the people were crowding about the shaft
where the great pump was to be set in motion and where work-people were
busy still trying to get it ready. Hammers were clinking, spanners and
screw wrenches rattling on nuts, and the work in progress was being
patiently watched, the engine-house and boilers being for the time
unnoticed.

"Perhaps he's here, after all," said Gwyn at last, with a gasp. "Shall
we go in?"

Joe hesitated while you might have counted ten, and he looked
despairingly round, as if in the hope of seeing something that would
check him and render the venture unnecessary, for there was the sound as
of a thousand snakes hissing wildly, and to one unused to the behaviour
of engine boilers all this seemed preliminary to a terrible explosion,
with possible death for those who went inside.

"Yes, we must go in," sa