BELT r. CRITTENDBN. 63 �coverings for buildings." The specification says: "Our in- vention consists in a novel construction of a metallic sheath- ing for buildings, and similar structures, and is designed, more especially, to render the same fire-proof, although it is of great value as a protection against rain and snow. In the drawing, figure 1 represents a building with our improved sheathing applied to a portion of it; figure 2, a view showing the manner of making the joints ; figures 3, 4 and 6, seo- tional views showing different f orms of our improved device. Great inconvenience has heretofore been experienced in ap- plying metal sheathing to buildings, bridges, and similar structures, owing to the fact that the expansion and contrac- tion of the metal cause the nails to work out, and the metal to draw apart or wrinkle. The shrinkage and swelling of the wood to which the metal is nailed also tends to produce the same resuit, while the metal, coming against the wood, forms but little protection against fire. In addition to these diffi- culties, rain or snow, and even fire or fiames, often find their way in at the joints as they are at present constructed. �"In order to obviate these difficulties, and produce a sheath- ing which shall be proof against both water and fire, we make our sheathing of sheet metal, and provide each section with one or more corrugations, as shown in figures 1, 3 and 5 ; or it may be^made in the form shown in figure 4, in which case the metal is turned directly backward at each side, at a right angle to the face of the metal, and a flange then turned out- ward on each side, parallel to the face of the sheathing. It will be observed that in each case a space is left between the metal and the boards to which it is secured, which space is, of course, filled with air. It will also be seen that only a very small surface of the metal cornes in contact with the wood, and that, as the joints are formed bylapping the flange of one section over that of the adjoining section, there will in every case be a double thickness of metal at those points at which the metal and the wood do corne in contact. The joints between sections, falling one below the other, are formed as shown in figure 2, in which the sections each have the metal ����
