Blochairn and Newton Works near Glasgow, the remaining 30,000 tons. For the alterations made subsequently in the design, and the increase of section in various parts, a further quantity of about 16,000 tons was required, about one-half of which was supplied by the Steel Company of Scotland, and the other half by Dalzell's Iron and Steel Works at Motherwell, near Glasgow. The steel for the viaduct spans, about 3200 tons, is not included in the figures given above. The Clyde Rivet Company, Glasgow, supplied about 4200 tons of rivets.
_Fig._75,_Page_37.jpg)
Fig. 75. Tube drilling machine and travelling crane on drill road.
_Fig._76,_Page_37.png)
Fig. 76. Plan of No. 1 drill shed.
With regard to tests, one plate out of every fifty, picked out promiscuously, had a strip cut out of it which was planed on all four sides and tested for tensile stress in a 50-ton testing machine. The same proportion was observed in the case of bars. For transverse or bending tests a piece was cut off every plate and every bar, about 2 in. wide, and tested by being bent under the press to a radius of 11⁄2 in. thickness with the ends of the test-piece closed. As regards the steel supplied by the Steel Company of Scotland, all plates were rolled at the Blochairn Works, and all bars at the Newton Works.
Failures of the steel under test were of the rarest occurrence.
All steel was manufactured by the Siemens-Martin open-hearth process, and all plates, bars, tees, angles, and other pieces, were cut to length and shape as ordered and thus delivered at the works. About 6 per cent. of the total steel delivered was returned as scrap, or between 3000 tons and 4000 tons. A certain proportion of the steel delivered was used for temporary purposes only, and this will account for the difference between the total quantity delivered and that erected.
Drawings.
All detail drawings were made at the drawing offices attached to the works and submitted to the engineers previous to being passed into the workshops. If necessary, full-size drawings were made on the blackened floor of the large drawing loft, and from these all templates were made in wood. The templates were carefully cut to size, all holes drilled in them, and all necessary information and description branded upon the template in clear type. In certain cases, such as bracing bars, which recur several hundred times over, some of the bars themselves were used as templates. For the erection of the superstructure the tracings were transferred to sheets prepared by the ferro-prussiate process, by which the only part of the paper remaining white is that which underlies the full or dotted lines of the tracings. The drawing is, therefore, of white lines upon a deep blue ground.
Workshops.
Two principal divisions were made in regard to the construction, namely, between the tubular
