538 The Architectural Review and American Builders' Journal. [Feb., It is likewise evident, that, if any damp- ness should exist beneath the roof, it will escape at this point. Fig. 4 represents the cleat used for fastening the sheets in place. It is formed of the same size as the inside scroll, (Fig. 3.) Four or five of these cleats are locked in the inner scroll, and nailed to the sheathing, or the rafter, (if laid without sheathing,) as is frequently the case. The next sheet is hooked on, covering the fastening cleats of the preceding one, and protecting them from the weather. From this circumstance, it will be seen, that no nail holes are made in &y part of the roof. The ends of the sheets break joints, for the sake of convenience, appearance, and security ; and, if the roof runs up to a ridge, the ridge itself is formed by an angular gutter of the sheet metal, inverted, and hooked over in the ends of the sheets, as above described, so that no moisture, rain or snow can penetrate the roof. The sheets are made of sheet-iron, of ordinary thickness, weio-hinar one pound to the square foot ; and they are immersed in a brown, fire-and-water- proof paint, which thus enters into, and closes, the pores of the iron ; and effectu- ally protects both sides. Sheets of iron thus coated are impervious to the action of sulphuric acid, either diluted or con- centrated. In addition to the edge-rolls, or hooks, affording a thorough preventive of le- sions, arising from expansion and con- traction, they are very effectual against the force of winds. When the tornado of 1860 devastated Cincinnati, Ohio, but one, out of many of these roofs in that city, was damaged, and that slightly ; while very many tin and other metal roofs were utterly destroyed. While this patent is equally adapted to flat or steep roofs, one inch to the foot is all the slope required. It can be applied as a temporaiy roof, and afterwards be readily removed, and laid upon other premises, either per- manently or temporarily, without loss or injury. We have spoken of the superior claims of this covering where none but a light roof can be admitted ; and it follows, that this HgJityiess is no disadvantage in the roof of a solid pile. STAINED GLASS. FROM THE OLD AUTHORITIES, No. 1. The History and General Method. WHATEVER is now doing in Stained Glass, rests upon the well-ascertained and immutable princi- ples of chemistry, so that a success, in transparency, brilliancy, purity of tone, or beauty of color, can be repeated, to any extent, an indefinite number of times. But the earlier artists in glass, while often very successful, were only empirically so. They fused together a certain number of substances, at a guess ; and, if the process resulted in a hit, they followed the known proportions of the ingredients, whenever that particular color was needed thereafter, observing, also, all the steps of the process, as first taken ; when, presumptively, many of the ingredients employed added nothing
