5^6 
Paradoxical Phenomena in Ice-caves, [August, 
This assumption is supported by the fadl that, from the 
description, the mouth of the cave would be at least 80 feet 
above the level of the river, and it may be inferred that as 
no special mention is made of the position of the entrance, 
save that it is in the side of a bluff, the hill may be consi- 
dered as extending above the mouth of the cave to at least 
the distance of the latter from the river. 
The phenomenon, then, of ice being found there in the 
summer can be referred, 1 think, to the theory of the libe- 
ration of compressed air brought down from a considerable 
height by a stream of water falling or flowing through a 
natural conduit or fissure in the rock, embodying the prin- 
ciple of the ancient and well-known tromp used in the 
Catiline forge, and still in use in Corsica, Sardinia, Savoy, 
and many other places. 
It is only necessary to imagine such imperfection in the 
conduit or fissure at the initial point, which is supposed to 
be on the top of the bluff, or far up the mountain’s side, as 
would admit air to come in contact with the water after it 
had attained a velocity of more than i foot a second. When 
the air has reached the bottom, and is liberated in the cave, 
it will be from a pressure equal to the height of the column 
of water, and it will have lost by convection , in the mass 
through which the conduit passes, the heat due to its com- 
pression ; and on being liberated it will immediately absorb, 
from the air and the water in the cave, the heat which it 
has lost in its downward passage. 
“ The most remarkable fadt,” that the cave freezes only 
in summer, and as the cold of actual winter comes on the 
ice in the cave gradually melts and disappears, is caused, I 
will venture to state as an opinion, by the gradual freezing 
of the surface at the top of the bluff, or the source of the 
air, to a considerable depth, thus sealing up the aperture 
through which the air entered the conduit. 
Sir Roderick Murchison described a similar ice cave at 
Lletski, Russia, but gave no explanation as to the phe- 
nomena. 
Ice wells are to be found at the foot of Mount Mansfield, 
in Vermont, and are really incipient caves, without depth 
enough to be clear of ice in winter, from the fadt that the 
external winter temperature reaches the bottom or source of 
the summer ice . — Science Observer . 
