Page:Arts & Crafts Essays.djvu/170

 had its origin probably in the desire to strengthen the back and to resist the strain when a book is pulled by head or tail from the shelf.

(7) Boards, the sides of the cover, stiff or limp, thick or thin, in all degrees.

(8) Squares, the projection of the boards beyond the edges of the book. These may be shallow or deep in all degrees, limited only by the purpose they have to fulfil and the danger they will themselves be exposed to if too deep.

(9) Borders, the overlaps of leather on the insides of the boards.

(10) Proof, the rough edges of leaves left uncut in cutting the edges to show where the original margin was, and to prove that the cutting has not been too severe. 146