Photograph of a 'skewback' and tubes in construction. Relative proportions of the men and their work in this view afford an admirable illustration of the remarkable dimensions of the Bridge. The five tubes shown represent the bottom members, the vertical column, and two struts 8 feet in diameter. The bottom member on the right hand side is part of the first length of the span, and is continued at this angle until it meets first tie. Surrounding one or more of these tubes will be noticed a cylindrical cage composed of angle iron, hoops and bars, and protected by a fine mesh wire netting. To the upper part of these cages were bolted iron straps passing up and connected to the lower side of lifting girder, so that when the latter ascended it carried up the cage along with it. These cages, within which all the riveting of the vertical columns was effected, were designed to ensure the safety of the workmen, for which purpose they proved invaluable. The depth of each cage was sufficient to admit of a 16 feet plate being riveted up without a hoist, the working space allowed between tube and netting being 4 feet. The difference of shades upon the horizontal tube in the foreground of picture is only due to the fact that it was being used at that date as a suitable surface for testing various samples of light coloured paint. Transcription from: Philip Phillips, 'The Forth Railway Bridge', Edinburgh, 1890.