The back when properly rounded should be about a third of a circle, according to the present mode, but in olden times they were made almost flat. They were not rounded as now done, but the swelling caused by the thread used made quite enough rounding when put in the press for backing.
Flat back books have a certain charm about them, the more so if in other respects they are properly forwarded. The theory is altogether averse to practical binding. I have always been given to understand that we round our books in order to counteract the tendency of a book to sink in and assume a convex back. Any old well-used book bound with a flat back will show at once this defect.
Messrs. Hopkinson and Cope, of Farringdon Road, London, manufacture a rounding machine. They claim that this machine will round 600 books per hour, and that any desired "round" may be given to the book with great uniformity.
CHAPTER XII.
Backing.
The boards required for backing, called backing boards, should always be the same length as the book. They are made somewhat thicker than cutting boards, and have their tops planed at an angle, so that the sheets may fall well over.
Hold the book in the left hand, lay a board on one side, a little away from the back, taking the edge of the top sheet as a guide, the distance to be a trifle more than the thickness of the boards intended to be used. Then
