Page:Popular Science Monthly Volume 37.djvu/177

Rh Alongside of the cutter's wheel one sees a corner of the atelier devoted to a species of cutting in miniature, which goes under the name of engraving. The cutting instrument is a small copper disk, sometimes as tiny as a dentist's tool, and sometimes several inches in diameter. It is mounted with its axis horizontal, and is made to rotate very rapidly. The cutting is lone underhand,



instead of overhand, as in the former operation, which means, in the language of the outside world, that the article to he engraved is brought into contact with the rotating disk from beneath, instead of being pressed against its upper surface. The disk is supplied with a mixture of emery and oil. This is the real cutting agent; the disk simply applies it. In almost all cases the work is done solely by the eye, without any guiding lines