It was perhaps imprudent to venture so far into the crypt. Pooh! they never thought of how they were to get back.

The gallery was practicable, not very winding. They met with no noxious exhalations, nor did any chasm bar the path. There was no reason for stopping for a whole hour; James Starr, Madge, Harry, and Simon Ford walked on, though there was nothing to show them what was the exact direction of this unknown tunnel.

And they would no doubt have gone farther still, if they had not suddenly come to the end of the wide road which they had followed since their entrance into the mine.

The gallery ended in an enormous cavern, neither the height nor depth of which could be calculated. At what altitude arched the roof of this excavation--at what distance was its opposite wall-- the darkness totally concealed; but by the light of the lamp the explorers could discover that its dome covered a vast extent of still water-- pond or lake--whose picturesque rocky banks were lost in obscurity.

"Halt!" exclaimed Ford, stopping suddenly. "Another step, and perhaps we shall fall into some fathomless pit."

"Let us rest awhile, then, my friends," returned the engineer. "Besides, we ought to be thinking of returning to the cottage."

"Our lamp will give light for another ten hours, sir," said Harry.

"Well, let us make a halt," replied Starr; "I confess my legs have need of a rest. And you, Madge, don't you feel tired after so long a walk?"

"Not over much, Mr. Starr," replied the sturdy Scotchwoman; "we have been accustomed to explore the old Aberfoyle mine for whole days together."

"Tired? nonsense!" interrupted Simon Ford; "Madge could go ten times as far, if necessary. But once more, Mr. Starr, wasn't my communication worth your trouble in coming to hear it? Just dare to say no, Mr. Starr, dare to say no!"

"Well, my old friend, I haven't felt so happy for a long while!" replied the engineer; "the small part of this marvelous mine that we have explored seems to show that its extent is very considerable, at least in length."

"In width and in depth, too, Mr. Starr!" returned Simon Ford.

"That we shall know later."

"And I can answer for it! Trust to the instinct of an old miner! It has never deceived me!"

"I wish to believe you, Simon," replied the engineer, smiling. "As far as I can judge from this short exploration, we possess the elements of a working which will last for centuries!"

"Centuries!" exclaimed Simon Ford; "I believe you, sir! A thousand years and more will pass before the last bit of coal is taken out of our new mine!"

"Heaven grant it!" returned Starr. "As to the quality of the coal which crops out of these walls?"

"Superb! Mr. Starr, superb!" answered Ford; "just look at it yourself!"

And so saying, with his pick he struck off a fragment of the black rock.

"Look! look!" he repeated, holding it close to his lamp; "the surface of this piece of coal is shining! We have here fat coal, rich in bituminous matter; and see how it comes in pieces, almost without dust! Ah, Mr. Starr! twenty years ago this seam would have entered into a strong competition with Swansea and Cardiff! Well, stokers will quarrel for it still, and if it costs little to extract it from the mine, it will not sell at a less price outside."

"Indeed," said Madge, who had taken the fragment of coal and was examining it with the air of a connoisseur; "that's good quality of coal. Carry it home, Simon, carry it back to the cottage! I want this first piece of coal to burn under our kettle."

"Well said, wife!" answered the old overman, "and you shall see that I am not mistaken."

"Mr. Starr," asked Harry, "have you any idea of the probable direction of this long passage which we have been following since our entrance into the new mine?"

"No, my lad," replied the engineer; "with a compass I could perhaps find out its general bearing; but without a compass I am here like a sailor in open sea, in the midst of fogs, when there is no sun by which to calculate his position."

"No doubt, Mr.