mote point from the entrance, and the lowest point beneath the surface. In a direct line from the entrance it was about six miles, but considerably more by the winding route which they had traversed. The barometer indicated five hundred and twenty-five feet below the level of the entrance. "The hills above the entrance," said the professor, "are at least four hundred feet high, so that the rocks overhead are about the fifth part of a mile thick."
In the excitement and novelty of the excursion, the ladies had quite forgotten the timidity with which they had set out. But they were now seized with a nervous terror at the thought of being buried many miles deep in the earth with a mountain over their heads. They had also become much fatigued, and thoughts of the long and toilsome return, with its rugged hills and passes, and the Auger Hole, filled them with dismay. They begged their companions to return at once.
"Lunch first," said one of the guides.
"I fear we have been imprudent in bringing the girls so far," whispered the doctor to the professor. "They are quite exhausted already."
In the fairy palace they sat down upon a group of convenient stones, and unpacked the generous supplies which the guides carried in their baskets. The long walk in the pure air of the cave had sharpened their hunger; the professor had added to the store two bottles of good sherry, and the strength and spirits of the ladies were soon restored.
"It is truly a unique place for a pic-nic," said Pauline.
"This is certainly the fairy-land we used to read about in the story books. We shall presently see the palace filled with busy gnomes, or Queen Mab and her court coming through yonder archway. I hope the gnomes won't be angry, and block up the passages, so that we can't get out."
The suggestion filled the other girls with horror. "Suppose the rocks should fall somewhere in a narrow place, and shut us in!" said Blanche.
"Not much danger," responded one of the guides, "though big rocks do sometimes come down."
"But suppose it should happen," persisted Blanche. "What would be done?"
"O, we've got that all arranged," said the guide. "They know at the house about how long we ought to be gone, and if we are much over time they send after us."
"But supposing they should find us blocked in, what could they do?"
"Raise the country and dig us out. Plenty of hands would do it in no time."
The bare possibility was sufficiently unpleasant to think of, and the ladies were now nervously anxious to proceed upon their return.
On the way the professor made his scientific observations and memoranda. The temperature in all parts of the cave was found to be fifty-four degrees of Fahrenheit, which he was told does not vary more than a degree or two during the entire year. At various points faint currents of air were perceptible, flowing in different directions at different parts of the cave. The professor was of opinion that this phenomenon indicated other openings besides the entrance, causing varying draughts in different directions according to the temperature of the external air and the direction of the wind. No vegetation of any kind is found in the cave, and the air is therefore not only dry but perfectly free from decomposed organic matter. Its purity is such, that the bodies of bats and other
