This thin shell of copper can be bent and crumpled up; it could not be used for printing in its present state, and it passes through a process called “backing up.” A thin coating of tin is applied to the back, when it is put face downward in a shallow dish, and kept in place by a number of small elastic rods. Then it is hung over a flat cauldron filled with melted type-metal, and lowered to rest in it. When the plate has acquired the same degree of temperature as the metal, the latter is ladled and poured over the plate, filling up all the hollows and indentations, and forming a solid back of lead. The coating of tin is first applied, as lead will not adhere to copper. The plate, being now ready for the planing, beveling, picking, and correcting of stereotype plates, goes through the same process that we have before described. When a book is to be bound, the pile of sheets which form it is made even at the back, and a saw, working by steam, cuts shallow grooves across the back, for the twine over which the sewing is done. Two girls are pictured sewing at their frames,--passing the needle through the fold of the sheet and round the upright twine, adding one sheet at a time to the pile, until the entire book is sewed. In the large apartment called the forwarding-room, the remaining processes of finishing are done. The rough and uncut edges of the book are made smooth by means of a cutting machine called the “guillotine.” The edges of a number of books can be cut at a time, by being secured on a movable bed, which rises so as to bring them under a stationary knife, which cuts them smoothly as they are pressed against it. There is also a backing-machine, for rounding the backs of books. The book is placed in a vise, and held near the edge of the back; and the man, working a treadle, moves a heavy roller over the back, thus drawing up the sheets in the centre; this is that the cover may be made fast to the book, the sides of the cover fitting tightly; the limp back is like a hinge. The stiff pasteboard covers are made by themselves; for instance, if a thousand copies of a book are to be made, while the folding and sewing of the thousand books is going on in one part of the building, in another two or three men are at work making cases; and when each is finished, they are put together. [Illustration: Laying on Gold Leaf.] [Illustration: FORWARDING ROOM.] But the stamped name on the back or ornamental work is done on the cases, after they are covered with cloth, and before the books are fastened into them. A brass die, or brand, is made of the title of the book; then the covers which are to be stamped are taken by the gilders, who first rub the white of an egg over the surface to be stamped, and upon that lay thin gold leaf, of gossamer lightness. [Illustration: Burnishing Gilt Edges.] In the picture three girls are laying on the gold leaf with their pallet knives.