Page:Library Construction, Architecture, Fittings, and Furniture.djvu/93

Rh cases of maps, plans, &c. It will be seen that they slide on rollers and so are easily withdrawn and replaced. In the sliding shelf used for the same purpose in the Bibliothèque Nationale, Paris, the edge of the shelf is grooved, and slides along a strip of metal fixed to the uprights of the bookcases. The back of the shelf has a slight projection at right angles, which acts as a stop, and prevents the book being pushed past the edge of the shelf.

At the Liverpool Public Library the most valuable and handsomely-bound volumes are kept in bookcases with glass doors. The large folios lie flat on iron rollers covered with soft cloth, three of them forming a shelf. The rollers are removable, and can be adjusted to any height required. They have a central pin at each end on which they revolve, which fits into grooves made in strips of metal. Three of these are sunk into each side of the uprights of the bookcases, back and front.

In libraries where the readers are allowed access