The system of chaining, as adopted in this country, would allow of the books being readily taken down from the shelves, and laid on the desk for reading. One end of the chain was attached to the middle of the upper edge of the right-hand board; the other to a ring which played on a bar set in front of the shelf on which the book stood. The fore-edge of the books, not the back, was turned forwards. A swivel, usually in the middle of the chain, prevented tangling. The chains varied in length according to the distance of the shelf from the desk. The bar was kept in place by a rather elaborate system of iron-work attached to the end of the bookcase, and secured by a lock which often required two keys—that is, the presence of two officials—to open it. To illustrate this I will shew you a sketch of one of the bookcases in Hereford Cathedral.