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SECTION XXIV.

The circular Line.

The mother draws before the child a circle, and says, this line, pointing to 5, is called a circular line; and the interior space, pointing to a, a circle.

Mother. Can you draw a circular line? Draw four circular lines. The drawing these lines must be practised from right to left, and from left to right. The mother makes a point in the middle of the circle, saying, this point is called the centre of the circle. Draw a circular line, and try to find the centre.

SECTION XXV.

The Curve Line or Arch.

Mother. This line is called a curve. Draw three, four, &c. curves or arches. The mother, pointing to b, says, ^-^r-v^ this is the convex, and pointing to a, this is the concave side of the curve or arch. Show me the convex side. Can you point out the concave side?

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SECTION XXVI.
Of Circular Parallel Lines.

Mother. Can you draw two circular parallel lines? If the child cannot do it, the mother draws them.

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Draw two parallel curves or arches; three not parallel curves; three parallel, and two not parallel curves, &c.

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SECTION XXVII.
Of curve-lined Angles,

The mother draws the two angles, a and b, saying, the angle a is formed of two concave sides, and is called a concave angle: b formed of two convex

sides, and is called a convex angle. The third is composed of a convex and a concave side, and is therefore called a mixed angle.

Draw concave, convex, and mixed angles.

Draw three concave, four convex, and two mixed angles.

Represent every thing you know of the circular line on your slate.

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SECTION XXVIII.

Of two-angled Curve-lined Figures.

Mother. Here are two-angled figures: the first composed of mixed angles;

the second of convex;

and the third of concave angles.

Draw a figure with two concave angles.

Draw three two-angled figures, with convex sides, &c.

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Draw four concave-angled triangles. Draw three convex-angled triangles with interior angles—with exterior angles. Draw a triangle of one concave and two convex angles, &c.

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