THE MAMMOTH CAVE. 4] 
The opening surrounding the mouth of the 
Cave is irregularly funnel-shaped; the walls 
being steep, and forty or fifty feet in height, 
and between fifty and one hundred feet across 
the top of the funnel. 
“Trees,” says Taylor, “grow around the edges 
of the pit, almost roofing it with shade; ferns 
and tangled vines fringe its sides; and a slender 
stream of water falls from the rocks which arch 
above the. entrance, dropping like a silver veil 
before the mysterious darkness beyond.” 
At nearly all seasons a mist or fog may be 
seen hanging over the mouth of the Cave. 
When the external air is warmer than that of 
the Cave, the mist is produced by the condensa- 
tion of the moisture of the former by the 
reduced temperature of the latter. On the 
contrary, if the temperature of the external 
atmosphere is lower than that of the Cave, the 
moisture of the air of the latter is condensed in 
a similar manner. 
When the temperature of the outer air is the 
same as that of the Cave, no fog or cloud is 
observable about its mouth. 
The entrance of the Mammoth Cave, at an 
early period of its history, as has already been 
stated by Mr. Gorin, was situated about half a 
4* 
