Sketching requires some little training, but with the apparatus here illustrated an inexperienced person can obtain excellent results. The apparatus is made of a box 8 in. deep, 8 in. wide and about 1 ft. long. A double convex lens, G, is fitted in a brass tube which should have a sliding fit in another shorter and larger tube fastened to the end of the box. A mirror, II, is set at an angle of 45 deg. in the opposite end of the box. This reflects the rays of light passing through the lens to the surface K, which may be either of ground or plain glass. The lid or cover EF protects the glass and. keeps the strong light out when sketching. The inside of the box and brass tube are painted a dull black.
In use, the device is set with the lens tube directed toward the scene to be painted or sketched and the lens focused so the reflected picture will be seen in sharp detail on the glass. Select your colors and put on the respective colors depicted on the glass. If you wish to make a pencil drawing, all you have to do is to fill in the lines in the picture on the ground glass. If a plain glass is used, place tracing paper on its surface, and the picture can be drawn as described.