The search for material ended, the work of construction may begin. Two duplicate copies of the cartoon are first made. One operation suffices to accomplish this. The cartoon is laid on a. large table, and beneath it are two sheets of similar paper and two sheets of ordinary black transfer paper arranged alternately. Bypassing a small revolving wheel over the outlines of the cartoon, the tracings are quickly and accurately made. Each space is then numbered correspondingly on both tracings, and one of them is cut up to make patterns for the glass-cutter. An ingenious dissecting instrument is used for this purpose. It consists of a pair of double-edged shears, which, in cutting, removes a strip of paper just the width of the lead which will separate the fragments of glass when they are finally bound together. In this way each pattern is precisely the size required. When the glass is ready to be put together in the window, there is very little coaxing to be done to get it into place.
The picture-window has now reached the most critical stage in its development. The paper patterns are to find suitable counterparts in glass, and upon the nicety with which this substitution is accomplished depends the effect of the entire work. Nothing is left undone that will assist the glass-cutter in forming correct color-judgments. Throughout the entire process, and here particularly, the work progresses under precisely those conditions that are best calculated to make surprises and incongruities impossible when the whole shall be completed. A sheet of plain glass, the size of the cartoon, is laid over the undissected tracing. Outlines of the intended lead bands are then painted on the clear glass in black lines of corresponding width. On the model thus prepared the paper patterns are stuck by means of a little wax. It is now ready to be taken to the figure-room, where it is placed directly in front of a large window, and the slow work of substituting colored glass for paper begins. The position in which the completed window is to be placed must constantly be borne in mind, and the treatment adopted be made to conform to the requirements of light and neighborhood. A window that will be effective when seen against a clear northern sky will probably be somewhat dull if turned to some other point of the compass and seen against a dark background of brick walls and shadows, while a window that would be a delight under these more somber conditions would be insupportably glaring against the stronger light. Consideration must also be paid to whether the window is to be seen commonly at long or short range, and to the general color tone of neighboring windows and walls.
Piece by piece the paper patterns are removed, and the shaped fragments of glass take their place. Each fragment is obtained by repeated trials until just the right effect is secured. When the