FEB. 1901. OBSERVATIONS ON INDIANA CAVES—FARRINGTON. 265 
The most unique feature of this cave is the pool at its end, 
excellently described by Blatchley.* 
The calcite crystals which line the walls of the pool are made up 
of the unit rhombohedron r (1011) and the unit prism of the first 
order m (1010). (Fig. 9.) The crystals have all grown in a direction 
at right angles to the plane of their attachment. The prism is quite 
short, and no crystals are doubly terminated. The crystals vary in 
size from quite minute to those the size of an ordinary acorn. It is 
noticeable that they increase in size toward the bottom of the pool. 
In order to determine whether it was 
commonly true that crystals increased 
in size toward the bottom of a solution, 
with the assistance of Mr. H. W. 
Nichols, I prepared solutions of a 
number of salts, placed them in long 
slender jars and then immersing strings 
vertically, noted the quantity and size of 
crystals deposited. In nearly every 
case the deposit took a marked conical 
form. The base of the cone and there- 
fore the greatest amount of deposit was 
at the lowest point inthe solution. It 
Fic. 9—Calcite, Coan’s Cave. was also generally true that the size of 
the crystals increased toward the bottom. The accompanying plate 
(Pl. XXXIII), showing strings of crystals obtained from solutions of 
copper sulphate, lead chloride and nickel-alum, illustrates this. Such 
results point to a greater concentration of solutions at the bottom, 
a principle already established with regard to solutions in general by 
Ludwig and Soret.} It may be worth while, however, to call atten- 
tion to this illustration of the principle, and to the fact that the 
size of crystals depends on the degree of concentration of the solution 
no less than on the time given for their formation. 
In this part of the cave stalactites and stalagmites of the ordi- 
nary type appear in close association with the crystal deposits just 
described. The formations have a similar origin in that they are 
both deposits of carbonate of lime from solution in water. They 
differ only in the condition that in the making of stalactites and stal- 
agmites the water was moving, while in the making of crystals it was 
still. If I am correct in this conclusion the converse of the principle 


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