In a few minutes their young guide returned, leading Harry Mule, whose swinging collar-lamp and wondering expression struck Miss Nellie as so comical that she could not help laughing at him.
"Haw! he-haw, he-haw, he-haw!" brayed Harry Mule, in answer to the unaccustomed sound; and at this greeting the girl laughed more heartily than ever.
The mule was hitched to the car, Derrick sprang in front, cracked the whip that had hung about his neck, and they started on what, to two of them at least, was the most novel ride they had ever undertaken.
When they reached his stable Harry Mule stopped short and refused to go on.
"What is the matter?" asked Miss Nellie.
"I expect he wants us to go in and see his house," answered Derrick.
"Why, I never heard of such a funny mule. Do you suppose he knows we are visitors?"
"Of course he does," answered the boy, gravely; "and he knows that visitors always want to see the mine stable."
So they all went in to look at it. In the long, low, narrow chamber, hewn from solid rock, were thirty stalls. Several of them were occupied by spare mules, who turned an inquiring gaze at the visitors, and blinked in the light of their lanterns. At one end were bales of hay and bags of oats, while just outside the door stood a long water-trough, which, as mine water is unfit for use, was supplied from above-ground through iron pipes brought down the slope. In spite of living in a continual midnight, so far from pastures and the light of day, which some of them did not see from one year's end to another, these mine mules were fat and sleek, and appeared perfectly contented with their lot.
Apparently satisfied that justice had been done to his place of abode, Harry Mule offered no further objection to moving on, when they again got into the car, and the stable was quickly left behind.