The edge of the oasis of Vitor is the contour line along which the irrigating canal runs.

Holt, Rinehart & Winston, Inc. (PWH); 18Feb70; R479961. DOALL CO. DoAll contour saws.

But if there is no stream line, does the contour bend show a valley or a ridge? First of all, there is a radical difference between the bend of a contour round the head of a valley and its bend round the nose of a ridge, Compare on the map the valleys V and the ridges

Away towards the north, too, the landscape for many miles is limited only by the same horizon of sea, so that we seem to be looking at a section of a very large scale contour map of England.

And just as truly as every bend in that high-tide mark turns out around a promontory, or in around a bay, so will every bend in a contour stand for a hill or a valley, pointing to the lowlands if it be a hill, and to the height if it mark a valley.

The rest of "hill, valley, hill," will always solve the problem when there are not enough stream lines shown to make evident at once whether a closed contour marks a pond or a hill.

The contours go thus: [Illustration] The streams flow down the valleys, and the sharp angle of the contour points always up stream.

On the little map you have drawn you have introduced all the varieties of ground forms there are; therefore all the contour forms.

So on the wall's outside we stand, Admire the keyhole's contour grand And gateposts' sturdy granite; But, ah, is Science safe, we say, With one who treats Trustees this way?