BOLE.—A red earthy mineral, resembling clay in character, used in the preparation for gilding edges.
BOLT.—The fold in the head and foredge of the sheets. The iron bar with a screw and nut which secures the knife to the plough.
BOSSES.—Brass or other metal ornamentations fastened upon the boards of books; for ornament or preservation.
BROKEN OVER.—When plates are turned over or folded a short distance from the back edge, before they are placed in the volume, so as to facilitate their being turned easily or laid flat, they are said to be broken over. When a leaf has been turned down the paper is broken.
BURNISH.—The gloss produced by the application of the burnisher to the edges.
BURNISHERS.—Pieces of agate or bloodstone affixed to convenient handles.
CANCELS.—Leaves containing errors which are to be cut out and replaced by corrected pages (see ASTERISK).
CAP.—The envelope of paper used to protect the edges while the volume is being covered and finished.
CASE-WORK.—When the cover is made independent of the book, the book being afterwards fastened into it. Refers principally to cloth and bible work.
CATCH-WORD.—A word used and seen in early printed books at the bottom of the page, which word is the first on the following page. To denote the first and last word in an encyclopædia or other book of reference.