Secure two extra slides for the plate holders and cut one corner out on one of , as shown in Fig. 1. Make a hole in the other, as shown in Fig. 2. With a lead pencil draw on the ground glass one line vertical and one horizontal, each in the center. This will divide the ground glass into four equal parts. Four Photos on One Plate

Illustration: Four Photos on One Plate

Focus the camera in the usual manner, but get the picture desired to fill only one of the parts on the ground glass. Place the plate-holder in position and draw the regular slide; substitute one of the slides prepared and expose in the usual way.

If a small picture is to be made in the lower left-hand corner of the plate, place the prepared slide with the corner cut, as shown in Fig. 1. The slide may be turned over for the upper left hand corner and then changed for slide shown in Fig. 2 for the upper and lower right-hand corners.

Imitating Ground Glass

Make a mixture of white lead in oil, 1 part; varnish, 3/4 part; turpentine, 1/4 part, and add sugar of lead as a dryer. Make a very thin paint of this and use a broad, flat brush, says Master Painter. With care you may succeed in getting the paint on quite evenly all over, which is desirable. One coat will do. If it becomes necessary to remove this coating for renewal, it may be effected by an application of potash lye, or the old may be renewed by a coating of a mixture of 2 parts hydrochloric acid, 2 parts white vitriol, 1 part sulphate of copper (blue vitriol) and 1 part of gum arabic, applied by means of a brush.

A Ground Glass Substitute

Ordinary plain glass coated with the following mixture will make a good ground glass substitute: Dissolve 18 gr. of gum sandarac and 4 gr. of gum mastic in 3-1/2 dr.. of ether, then add 1 2-3 dr. benzole. If this will be too transparent, add a little more benzole, taking care not to add too much. Cover one side of a clear glass and after drying it will produce a perfect surface for use as a ground glass in cameras. -Contributed by Ray E. Strosnider, Plain City, Ohio.