Manual of Drawing; To Prepare Students for the Regents' Examination in Drawing (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1896 Excerpt: ...angle. If two curves meet at a point with their convex sides toward each other the angle is called a sistroid angle. A lunular angle is formed by two curves meeting at a point with the convex side of one curve toward the concave side of the other. A mixed angle is formed by a straight line and a curve meeting at a point. A horned angle is formed by a straight line and the arc of a circle which meet at a point. The size of an angle depends on the degree of opening between its sides or the difference in their direction, and not on the length of its sides. A reentrant angle is one whose vertex points inward toward the center of the figure of which it is a part. Let the student draw examples of all the above different kinds of angles, using a ruler and a compass. With three lines let him make two, three, four, five, six, seven, eight, nine, ten, eleven, and twelve angles. Figures. Figures with reference to the character of their boundary lines may be (1) Rectilinear, including (a) triangles, ( ) quadrilaterals, and (c) polygons. (2) Curvilinear, including (a) those with a single bounding curve, as circles, ellipses, etc., and (b) those having more than one curve for their boundaries. (3) Mixtilinear, including those having for their boundaries straight lines and curves. Triangles. A triangle or a trilateral is a plane figure having three straight sides and three angles. Triangles are named either from the comparative lengths of their sides or from the size of their angles. 1. With reference to the comparative length of their sides, we may have equilateral, isosceles, and scalene triangles. If the sides are all of the same length the triangle is called equilateral, equiangular or equal sided. Also it is sometimes called a trigon. If only two sides are of th...