Fig. 1.
The Line of Beauty, as it is called, is the two curves combined; commencing at the top, making first the left and then the right line, equal in length, forming a compound curve, the basis of two-thirds of all the capital letters. A combination of curves lying horizontally, as in fig. 2, gives the line which is formed by the meeting of the lips, from these different lines our sketches from nature are made up.
Fig. 2.
A curved line changes its direction at every point.
A circle is a figure comprehended by a single curve line, called its circumference, every part of which is equally distant from a point called the center. From a to b will be found the left, or convex, and from c to d the right, or concave curve. The whole may be made by a quick movement of the hand, with crayon, on the black-board, thus: Turn your right side to the board, place the crayon at the bottom, c, and with the elbow as the radius, carry the crayon toward the left from c to a, and so on until you reach the starting point, c, again, moving the hand at as rapid a rate as is possible.
Fig. 3.
Now, if these lines can all be drawn correct, and with freedom, take the equilateral triangle and practice it without a ruler.
