Fig. 93.—Adjustable Screw Binder ([Section 271]).
271.
271. Another variety of this French binder designed to secure adjustability of leaves is that shown below in the illustration ([Fig. 93]), wherein the leaves are clamped by the pressure of two wooden slats, which are drawn together by means of two or more endless screws turned by a key.
For this kind of binder it is necessary to notch the leaves to correspond with the screws.
The principle of the sheaf binders ([Section 282]) can also be applied to page catalogues, and very successful page books have been made up from the form illustrated in [Sections 286]-[87]. The most recent methods of loose-leaf ledgers have also great possibilities for catalogues, and are probably to be preferred to any book manuscript type other than the sheaf.
The whole of the devices just described are so arranged that leaves can be inserted, to a more or less limited extent, at any point. The British Museum type does not provide for unlimited additions, nor for any subsequent division of volumes, without much trouble and rebinding. The French and other adjustable leaved binders do allow for unlimited insertions, subject to the condition that the matter mounted on the pages must be redistributed. In an adjustable book new leaves can be inserted at any place till the volume is full, and then the contents may be divided and two books used, this subdivision and spreading being continued as the entries increase in number.
272.
272. A form of page catalogue combining the powers of inserting new leaves at any point, and moving single entries about without having to paste them down or lift them up, is called the Rudolph Indexer. It consists in its book form of thick cardboard leaves, to which metal flanges are secured, down each margin. Each leaf is provided with a double-hinged fastening, which enables it to be hooked on to any adjoining leaf, so as to form a volume of any desired thickness, to which a pair of covers can be attached. The catalogue entries are written or printed on narrow cards, and these are slipped under the flanges, which secure them by either end. [Fig. 94] shows at a glance the appearance of this form of page catalogue.
Fig. 94.—Rudolph Indexer Book ([Section 272]).