"Not much!" said Will, turning back to the dike. "Just look here a
minute!"
Seating himself on the dike top, he took a book from his pocket and
began making rough diagrams on the fly leaf.
[Illustration: Diagram of Warping Dykes.]
CHAPTER III.
A PIECE OF ENGINEERING.
Ted craned his neck eagerly to watch the movements of Will's pencil.
"You know," began Will, with his head on one side, "in some parts of
the world, when they want to make the tide work for them, they use
things they call 'warping dikes.' These run on a slant out from the
shore toward the channel. They generally slope up stream pretty sharply.
The tide comes in, loaded right up with fine mud, flows over and into
and around the long lines of warping dike, then stops and begins to
unload. Now, you see, when there are no warping dikes, the current
has nothing to delay it, so it soon gets going on the ebb so fast that
it washes away pretty near all it has deposited. But these warping dikes
bring in a new state of affairs. They so hinder the ebb that there is
more silt deposited, and at the same time there is less current on the
flats to carry the mud away. As the engineers say, there is not so much
'scouring'--a first-rate word to express it. Haven't you noticed how,
in some spots, the current seems to scour away all the mud and leave
naked stones and pebbles?"
"Yes," exclaimed Ted, "I get hold of the idea now. And when the warping
dikes have got their work in, what then?"
"Why, we'll dike the whole cove in.
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