When copying a collodion positive mounted on glass and varnished at the back, the first proceeding is to remove the varnish. It may be possible to do this by placing for a short time in a dish of methylated spirit and then wiping down with a tuft of wool. Try one edge and see whether the picture is affected. When the varnish is removed, a print or transparency can be made by contact in the usual pressure frame. A better plan would be to pin the picture to the wall with drawing pins, and copy through the camera in the usual manner. To obtain a copy the same size as the original, it may be necessary to make a conical front, place two cameras together, or otherwise increase the extension, which should be twice the focal length of the lens. Copying is merely photogi-aphing a picture at close quarters. The only difficulty is to avoid the reflection of bright objects in the shadows and the picture. Slow plates should be used, and a strong pyro-soda developer.