When the generating line of a cylinder or a cone becomes a tangent to the directrix, the cylinder or cone in general has an edge of regression along this generating line. The osculating plane of the directrix at the point of contact touches the surface along this edge.
Projections of curves of double curvature; infinite branches and their assymplotes, inflections, nodes, cusps, &c.
Change of planes of projection.
Reduction of scale; transposition.
Advantage and employment of curves of error; their irrelevant solutions.
Lessons 4–6. Modes of Representation for the Complete Definition of Objects.
Representation by plans, s, and elevation.
Projection by the method of contours. Representation of a point, a line, and a plane; questions relative to the straight line and plane. Representation of cones and cylinders; tangent planes to these surfaces.
Lessons 7–11. Modes of Representation which are not enough in themselves to define objects completely.
Isometrical and other kinds of perspective.