AT Harry's call, James Starr, Madge, and Simon Ford entered through the narrow orifice which put the Dochart pit in communication with the new mine. They found themselves at the beginning of a tolerably wide gallery. One might well believe that it had been pierced by the hand of man, that the pick and mattock had emptied it in the working of a new vein. The explorers question whether, by a strange chance, they had not been transported into some ancient mine, of the existence of which even the oldest miners in the county had ever known.

No! It was merely that the geological layers had left this passage when the secondary earths were in course of formation. Perhaps some torrent had formerly dashed through it; but now it was as dry as if it had been cut some thousand feet lower, through granite rocks. At the same time, the air circulated freely, which showed that certain natural vents placed it in communication with the exterior atmosphere.

This observation, made by the engineer, was correct, and it was evident that the ventilation of the new mine would be easily managed. As to the fire-damp which had lately filtered through the schist, it seemed to have been contained in a pocket now empty, and it was certain that the atmosphere of the gallery was quite free from it. However, Harry prudently carried only the safety lamp, which would insure light for twelve hours.

James Starr and his companions now felt perfectly happy. All their wishes were satisfied. There was nothing but coal around them. A sort of emotion kept them silent; even Simon Ford restrained himself. His joy overflowed, not in long phrases, but in short ejaculations.

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. Starr," replied Ford; "but pray don't compare our position with that of the sailor, who has everywhere and always an abyss under his feet! We are on firm ground here, and need never be afraid of foundering."

"I won't tease you, then, old Simon," answered James Starr. "Far be it from me even in jest to depreciate the New Aberfoyle mine by an unjust comparison! I only meant to say one thing, and that is that we don't know where we are."

"We are in the subsoil of the county of Stirling, Mr. Starr," replied Simon Ford; "and that I assert as if--"

"Listen!" said Harry, interrupting the old man. All listened, as the young miner was doing. His ears, which were very sharp, had caught a dull sound, like a distant murmur. His companions were not long in hearing it themselves. It was above their heads, a sort of rolling sound, in which though it was so feeble, the successive CRESCENDO and DIMINUENDO could be distinctly heard.

All four stood for some minutes, their ears on the stretch, without uttering a word. All at ............