212 THE MAMMOTH CAVE. 
phere,—for, as already stated, it contains less 
carbonic acid than the outer air,—but is refer- 
able solely to the complete silence and total 
absence of light. 
Owing to the purity of the atmosphere and the 
even temperature, even delicate persons are ena-— 
bled to take a much greater amount of physical 
exercise in the Cave than without. It is not an 
uncommon occurrence for an individual in dell- 
cate health to accomplish a journey of eighteen 
or twenty miles in the Cave, without suffering 
unusually from fatigue, who could not be pre- 
vailed upon to walk a distance of three miles on 
the surface of the earth. 
After having accomplished our first day’s jour- 
ney in the Cave, we remarked to one of the 
gentlemen connected with the hotel, that we 
supposed ladies must suffer extremely from 
fatigue in going through the Long Route. He 
replied that such was not the case; and stated 
that, as a general rule, ladies endure the journey 
much better than men; and added that it was 
not an uncommon occurrence for ladies, after 
coming out in the evening, from a walk of 
eighteen miles, to enter the ball-room and dance 
until two o’clock in the morning! 
