THE TWO GREAT SCULPTORS. 121 
often making a complete circle, and then, as the water 
drips from it day by day, it goes on growing and grow- 
ing till it forms a long needle-shaped or tube-shaped 
rod, hanging like an icicle. These rods are called 
stalactites, and they are so beautiful, as their minute 
crystals glisten when a light is taken into the cavern, 
that one of them near Tenby is called the " Fairy 
Chamber." Meanwhile, the water which drips on to 
the floor also leaves some carbonate of lime where it 
falls, and this forms a pillar, growing up toward the 
roof, and often the hanging stalactites and the rising 
pillars (called stalagmites) meet in the middle and form 
one column. And thus we see that underground, as 
well as aboveground, water moulds beautiful forms in 
the crust of the earth. At Adelsberg, near Trieste, 
there is a magnificent stalactite grotto made of a num- 
ber of chambers one following another, with a river 
flowing through them ; and the famous Mammoth 
Cave of Kentucky, more than ten miles long, is an- 
other example of these wonderful limestone caverns. 
But we have not yet spoken of the sea, and this 
surely is not idle in altering the shape of the land. 
Even the waves themselves in a storm wash against 
the cliffs and bring down stones and pieces of rock on 
to the shore below. And they help to make cracks 
and holes in the cliffs, for as they dash with force 
against them they compress the air which lies in the 
joints of the stone and cause it to force the rock apart, 
and so larger cracks are made and the cliff is ready 
to crumble. 
It is, however, the stones and sand and pieces of 
