--Mill: _The Realm of Nature_. (Copyright, 1892, by Charles Scribner's
Sons.)
EXERCISES
_A._ In your reading, notice how often the effects are indicated by the
use of some one of the following expressions: _as a result, accordingly,
consequently, for, hence, so, so that, thus._
_B._ Which sentences state causes and which state effects in the following
paragraphs?
1. The power of water to dissolve most minerals increases with its
temperature and the amount of gases it contains. Percolating water at
great depths, therefore, generally dissolves more mineral matter than it
can hold in solution when it reaches the surface, where it cools, and,
being relieved of pressure, much of its carbonic acid gas escapes to the
atmosphere or is absorbed by aquatic plants or mosses. Hence, deep-seated
springs are usually surrounded by a deposit of the minerals with which the
water is impregnated. Sometimes this deposit may even form large hills;
sometimes it forms a mound around the spring, over the sides of which the
water falls, while the spray, evaporating from surrounding objects, leaves
them also incrusted with a mineral deposit. Percolating water evaporating
on the sides and roof of limestone caverns, leaves the walls incrusted
with carbonate of lime in beautiful masses of crystals. Water slowly
evaporating as it drips from the roof of caverns to the floor beneath
leaves a deposit on both places, which gradually grows downward from the
roof as a _stalactite_, and upward from the floor as a _stalagmite_, until
these meet and form one continuous column of stone.
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