CONSTRUCTION X. THE ARCH LINE 163

§ 18. The varieties of the ogee curve are infinite, as the reversed portion of it may be engrafted on every other form of arch, horseshoe, round, or pointed. Whatever is generally worthy of note in these varieties, and in other arches of caprice, we shall best discover by examining their masonry; for it is by their good masonry only that they are rendered either stable or beautiful. To this question, then, let us address ourselves.

[Version 0.04: March 2008]