[Illustration: FIG. 83.--Millboard Dummy for Withdrawn Book (Section 248).] =248.= For books temporarily withdrawn a piece of millboard covered white on one side may be used in the form shown below (Fig. 83). This should have the author, number and title of the missing book written on the white side. One board of this sort can be used over and over again for different books, by simply adding the new title and obliterating the old one. This board can also be used instead of the block above illustrated (Fig. 82) if space is a matter of moment. The object of the tail in this form of board is to prevent the board from disappearing behind or getting lost among the other books. When placed between two books, with the projection overhanging the front of the shelf, it will always stick out so as to be seen readily, while it cannot very readily be pushed deep into the shelf because of the projection. [Illustration: FIG. 84.--Xylonite Label-holder (Section 249).] [Illustration: FIG. 85.--Tongued Metal Book-rest (Section 250).] [Illustration: FIG. 86.--Flanged Metal Book-rest (Section 250).] =249.= LABEL-HOLDERS for keeping all kinds of classification or other labels in place upon the fore-edges of shelves, close to the books which they indicate, are made in various forms. An old form was made out of tin or thin japanned iron, with a pair of flanges on the upper and lower edges to take a card-label. This was screwed or tacked on to the edge of the shelf and shifted when necessary. Another form of this holder is made precisely the same as regards the turned-over flanges to form grooves, but without the screw-holes, and has in addition a long projection to slide under the books on the shelf so as to keep in place. This can be moved easily, but it is very apt to be pulled out when books are removed. A simple, effective shelf label-holder is made from strips of transparent xylonite bent in a rectangular form, and pinned or screwed to the under-side of the shelf as illustrated (Fig. 84). This can be made to fit into shelves with either square or rounded edges, and keeps the labels clean, as it covers them over. The advantage of this form of label-holder is that it can be cut with a pair of scissors or a knife to any size if wanted only for simple shelf or class numbers. It is also easily adjusted or changed. [Illustration: FIG. 87.--Combined Book-rest and Shelf Guide (Section 250).] [Illustration: FIG. 88.--Yale Book-rest (Section 250).]