Book covers become soiled in handling and especially school books.  Various methods are applied for making a temporary cover that will protect the book cover.  A paper cover can be quickly made by using a piece of paper larger than both covers on the book when they are open.  Fold the paper on the long dotted line, as shown in Fig. 1.  When the folds are made the paper should then be just as wide as the book cover is high.  The ends are then folded on the short dotted lines, which will make it appear as shown in Fig. 2.  The paper thus folded is placed on the book cover as shown in Fig. 3.  —­Contributed by C. E. McKinney, Jr., Newark, N. J.

[Illustration:  To Protect Book Covers]

** How to Make Lantern Slides [127]

The popularity of lantern slides, and especially of colored ones, as a means of illustrating songs, has caused so large a demand for this class of work that almost any amateur may take up slide making at a good profit.  The lantern slide is a glass plate, coated with slow and extremely fine-grained emulsion.  The size is 3-1/4 by 4 in.  A lantern slide is merely a print on a glass plate instead of on paper.  Lantern slides can be made in two different ways.  One is by contact, exactly the same as a print is made on paper, and the other by reduction in the camera.  In making slides by contact, select the negative and place it in the printing frame and put the lantern plate upon it, film to film.  Clamp down the back and expose just as in making a print.  A good method of exposing is to hold a lighted match about 3 in. from the frame for three or more seconds according to the density.

Development is carried on in the same manner as with a negative.  The image should appear in. about a minute, and development should be over in three or four minutes.  If the exposure has been correct, the high lights will stay white throughout the development and will come out as clear glass after fixing.  It is best to use the developers recommended by the manufacturer of the plates used, the formulas being found in each package of plates.  It is best, also, to use a plain fixing bath, which must be fresh and kept as cool as possible in hot weather.

The lantern-slide film that is new on the market can be handled in the same manner as the glass-plate slide, except that the binding is different.  The results are the same and the slides are not so bulky to handle.  Being unbreakable, they are much used by travelers.  The manner of binding them for use in a lantern is described on the circular enclosed with the film.

[Illustration:  The Camera as It is Arranged in Front of the Window for Reducing the Size of a Picture, and the Method of Binding the Slides]