Man is largely indebted to streams for the variety and beauty of scenery.
Running water itself is attractive to young and old. A landscape without
water lacks its chief charm. A child instinctively finds its way to the
brook, and the man seeks beside the river the pleasure and recreation
which no other place affords. Streams have carved the surface of the land
into an endless variety of beautiful forms, and a land where stream
valleys are few or shallow is monotonous and tiresome. The most common as
well as the most celebrated beauty of scenery in the world, from the tiny
meanders of a meadow brook to the unequaled grandeur of the Colorado
canyons, is largely due to the presence and action of streams.

--Dryer: _Lessons in Physical Geography_.


In the above selection we find that each group of sentences is related to
some main topic. A more extended observation of good writing will give the
same result. Men naturally think in sentence groups. A group of sentences
related to each other and to the central idea is called a +paragraph.+


+38. Topic Statement.+--In the three paragraphs of the selection on page
67, notice that the first sentence in each tells what the paragraph is
about. In a well-written paragraph it is possible to select the phrase or
sentence that states the main thought. If such a sentence does not occur
in the paragraph itself, one can be framed that will express clearly and
concisely the chief idea of the paragraph. This brief, comprehensive
summary of the contents of a paragraph is called the topic statement.

In order to master the thought of what we read we must be able to select