Perhaps the greatest use of galvanized iron at present is found in the construction of bay windows. In this construction the essentials are lightness and strength, so that it is usual to construct a light framework of steel, upon which the metal finish is secured, as in Fig. 163. Cornices are run on steel or iron brackets secured to the brick wall or the steel frame, as may be found most available. These brackets are shaped to conform roughly to the outline of the cornice, and it is allowable to insert a reasonable amount of boarding to form a base for any broad washes of metal, as boarding thus placed, outside of the walls, and completely encased by metal, is not in any danger from fire. For heavy projecting cornices, the brackets should be made of steel angle irons securely built into the wall, or bolted to it, or to the steel skeleton.