i879»J Paradoxical Phenomena in Ice-caves . 525 
to have been as yet no cause assigned. A description of 
this cave is given in the same letter, of which description, 
so nearly as is possible, the accompanying illustration is a 
fair representation, as regards the main features of the case. 
There may be a few differences as regards the details of the 
cave, but so nearly as can be judged from the written 
description the drawing presents the elements necessary to 
the peculiarities of the cave. In the figure the cave will 
be seen represented as at the bottom of an inclined passage, 
the inclination being that noted in the description, and the 
dimensions and other particulars being as nearly as possible 
to the proper scale. The crevice mentioned in the descrip- 
tion may be imagined as a fault, which extends from the top 
of the cave to the top of the bluff, through which crevice 
mingled air and water finds its way to the cave. 
In regard to the mingling of air with a stream of descend- 
ing water, a quotation from the pamphlet of Mr. Frizzel, on 
the subject of the compression of air by such streams, 
would not be entirely out of order. On this subject he 
says — “ It is a matter of common observation that bubbles 
of air rise in still water with a very moderate velocity. The 
velocity depends somewhat on the size of the bubbles. 
Bubbles, such as issue from an orifice one-eighth or one- 
tenth of an inch in diameter, rise from a depth of 50 feet 
in about fifty seconds, moving rather less than 1 foot per 
second near the bottom, and rather more than that near the 
surface. It is plain that a bubble of air drawn into water 
that has a downward motion of more than 1 foot per second 
will be carried down and subjected, in its descent, to a con- 
tinually increasing pressure.” 
Considering, then, the description and the fadts above 
quoted, it would not be unfair to assume that there would 
be a possible compression of air contained in the water, on 
its liberation in the cave, of about 80 lbs. to the square inch. 
