was the entrance to
the narrow bay, where was the landing-place for our tourists, who meant
to return to Stirling by Callander.

Nell appeared completely worn out by the continued excitement of the
day. A faint ejaculation was all she was able to utter in token of
admiration as new objects of wonder or beauty met her gaze. She required
some hours of rest, were it but to impress lastingly the recollection of
all she had seen.

Her hand rested in Harry's, and, looking earnestly at her, he said,
"Nell, dear Nell, we shall soon be home again in the gloomy region of
the coal mine. Shall you not pine for what you have seen during these
few hours spent in the glorious light of day?"

"No, Harry," replied the girl; "I shall like to think about it, but I am
glad to go back with you to our dear old home."

"Nell!" said Harry, vainly attempting to steady his voice, "are you
willing to be bound to me by the most sacred tie? Could you marry me,
Nell?"

"Yes, Harry, I could, if you are sure that I am able to make you happy,"
answered the maiden, raising her innocent eyes to his.

Scarcely had she pronounced these words when an unaccountable phenomenon
took place. The Rob Roy, still half a mile from land, experienced a
violent shock. She suddenly grounded. No efforts of the engine could
move her.

The cause of this accident was simply that Loch Katrine was all at once
emptied, as though an enormous fissure had opened in its bed. In a few
seconds it had the appearance of a sea beach at low water. Nearly the
whole of its contents had vanished into the bosom of the earth.

"My friends!" exclaimed James Starr, as the cause of this marvel became
suddenly clear to him, "God help New Aberfoyle!"

CHAPTER XVI. A FINAL THREAT

ON that day, in the colliery of New Aberfoyle, work was going on in the
usual regular way. In the distance could be heard the crash of great
charges of dynamite, by which the carboniferous rocks were blasted.
Here masses of coal were loosened by pick-ax and crowbar; there the
perforating machines, with their harsh grating, bored through the masses
of sandstone and schist.

Hollow, cavernous noises resounded on all sides. Draughts of air rushed
along the ventilating galleries, and the wooden swing-doors slammed
beneath their violent gusts. In the lower tunnels, trains of trucks
kept passing along at the rate of fifteen miles an hour, while at their
approach electric bells warned the workmen to cower