this is the way."

They came at length to a small room at the end of a long corridor. It
was evidently from this room that the sound of machinery came, for the
nearer they came the louder it grew. The door was slightly ajar, and
looking in, the friends could see two men, evidently engaged on some
mechanical task. There was a fire of charcoal in the grate, and attached
to it a pair of small but powerful bellows, driven by a small motor. In
the heart of the fire was a metal crucible, so white and dazzling hot
that it was almost impossible for the eye to look upon it. Venner did not
fail to notice that the men engaged in this mysterious occupation were
masked; at least, they wore exceedingly large smoked spectacles, which
came to much the same thing. Behind them stood another man, who had every
appearance of being a master workman. He had a short pipe in his mouth, a
pair of slippers on his feet, and his somewhat expansive body was swathed
in a frock coat. Presently he made a sign, and with the aid of a long
pair of tongs, the white hot crucible was lifted from the fire. It was
impossible for the two men outside to see what became of it, but
evidently the foreman was satisfied with the experiment, for he gave a
grunt of approval.

"I think that will do," he muttered. "The impression is excellent.
Now, you fellows can take a rest whilst I go off and finish the other
lot of stuff."

"He's coming out," Venner whispered. "Let us make a bolt for it. It
won't do to be caught here."

They darted down the corridor together, and stood in an angle of a
doorway, a little undecided as to what to do next. The man in the frock