When the plate leaves the rougher’s hands the surface of the bevel has been ground so deep by the coarse sand that polishing at this stage is impossible. Consequently, in order to produce a surface fine enough to render it susceptible of a high and brilliant polish it must go through the various treatments we have mentioned. The emerier uses a fine grade of emery on a mill similar in construction to a roughing mill, which takes away considerable of the coarse surface given by the first cutting. Then it goes to the smoother, who reduces the roughness slowly by using a fine sandstone from England; then it goes to the white-wheeler who operates an upright poplar-wood wheel using powdered pumice stone as an abrasive; and then, as a last stage it reaches the buffer, whose method of operation is shown in the illustration. The buffer brings a high polish to the bevel by the use of rouge applied to thick felt which covers his wheel. [Illustration: SILVERING MIRROR PLATES.] [Illustration: The two photographs here are of the same building taken under contrasting conditions. The first picture was taken through a window glazed with common window glass. It is an extreme example, to be sure, but of a sort not infrequently seen. The second view shows the same building taken through a window of polished, flawless plate glass. An observing person can see this startling contrast any day as he walks along a residence street. At intervals a front window will be seen which gives a twisted, distorted reflection of the houses or trees on the opposite side: this is window glass. The other kind--the window that gives a sharp brilliant reflection--is _plate glass_. It is practically impossible to obtain superior reflecting quality from window glass. It can only be had from surfaces which have been ground and polished.]