nse stone is cast upon us,
and communication is interrupted by the breaking of the ladders in
the Yarrow shaft. We commence exploring. An experiment, by which the
existence of a new vein would be proved, is rendered impossible by
stoppage of fissures. Notwithstanding this, the examination is carried
out, the vein discovered. We return as we came, a prodigious gust of air
meets us, our lamp is broken, utter darkness surrounds us. Nevertheless,
we make our way along the gloomy passage until, on reaching the
entrance, we find it blocked up. There we were--imprisoned. Now, Jack,
don't you see in all these things a malicious intention? Ah, yes,
believe me, some being hitherto invisible, but not supernatural, as you
will persist in thinking, was concealed in the mine. For some reason,
known only to himself, he strove to keep us out of it. WAS there, did
I say? I feel an inward conviction that he IS there still, and probably
prepares some terrible disaster for us. Even at the risk of my life,
Jack, I am resolved to discover him."

Harry spoke with an earnestness which strongly impressed his companion.
"Well, Harry," said he, "if I am forced to agree with you in certain
points, won't you admit that some kind fairy or brownie, by bringing
bread and water to you, was the means of--"

"Jack, my friend," interrupted Harry, "it is my belief that the friendly
person, whom you will persist in calling a spirit, exists in the mine as
certainly as the criminal we speak of, and I mean to seek them both in
the most distant recesses of the mine."

"But," inquired Jack, "have you any possible clew to guide your search?"

"Perhaps I have. Listen to me! Five miles west of New Aberfoyle, under
the solid rock which supports Ben Lomond, there exists a natural shaft
which descends perpendicularly into the vein beneath. A week ago I went
to ascertain the depth of this shaft. While sounding it, and bending
over the opening as my plumb-line went down, it seemed to me that the
air within was agitated, as though beaten by huge wings."

"Some bird must have got lost among the lower galleries," replied Jack.

"But that is not all, Jack. This very morning I went back to the place,
and, listening attentively, I thought I could detect a sound like a sort
of groaning."

"Groaning!" cried Jack, "that must be nonsense; it was a current of
air--unless indeed some ghost--"

"I shall know to-morrow what it was," said Harry.

"To-morrow?" answered Jack,