paper a figure of the same shape and
you will have a contour showing the shape of the bit of ground
where you poured your water.

Next, with your heel gouge out on one edge of your little pond
a small round bay. The water will rush in and the water-mark
on the soil will now be shaped something like figure 7.

Alter your drawing accordingly, and the new contour will show
the new ground shape.

Again do violence to the face of nature by digging with a stick a
narrow inlet opening out of your miniature ocean, and the watermark
will now look something like figure 8.

Alter your drawing once more and your contour shows again the
new ground form. Drop into your main pond a round clod and you
will have a new watermark, like figure 9, to add to your drawing.
This new contour, of the same level with the one showing the
limit of the depression, shows on the drawing the round island.

Drop in a second clod, this time long and narrow, the watermark
will be like figure 10, and the drawing of it, properly placed,
will show another island of another shape. Your drawing now will
look like figure 11.

It shows a depression approximately round, off which open a round
bay and a long narrow bay. There is also a round elevation and a
long, narrow one; a long, narrow ridge, jutting out between the
two bays, and a short, broad one across the neck of the round
bay.

[Illustration: Fig. 6. Fig. 7. Fig 8. Fig. 9. Fig 10. Fig. 11.]

Now flood your lake deeply enough to cover up the features you
have introduced. The new water line, about as shown by the dotted
line in figure 11, shows the oblong shape of the depression at a
higher level; the solid lines show the shape farther down; the
horizontal distance between the two contours at different points
shows where the bank is steep and where the slope is gentler.

Put together the information that each of these contours gives
you, and you will see how contours show the shape of the ground.
On the little map you have drawn you have introduced all the
varieties of ground forms there are; therefore all the contour
forms.

The contours on an ordinary map seem much more complicated, but
this is due only to the number of them, their length, and many
turns before they finally close on themselves. Or they may close
off the paper. But trace each one out, and it will resolve itself
into one of the forms shown in figure 11.

Just as the high-tide line round the continents of North and
South Ame