Of the pyramidal shadow.

The pyramidal shadow generated by a parallel body will be so much narrower than the shadowing body as the simple derivative shadow is cut at a greater distance from its shadowing body.

Of the simple derivative shadows.

The simple derivative shadow is of two sorts, that is, one finite in length and two infinite. And the finite one is pyramidal; and of the infinite ones, one is columnar and the other dilatable, and all three are of rectilinear sides. But the concurrent shadow, that is, the pyramidal, arises from a shadowing body smaller than the luminous body; the columnar arises from a shadowing body equal to the luminous body; and the dilatable from a shadowing body larger than the luminous body, etc.

Of the composite derivative shadows.

The composite derivative shadows are of two sorts, that is, columnar and dilatable.