The Civil engineer and architect's journal, scientific and railway gazette (1839)
London : [William Laxton] · leaf 401
•miJIiijjiliiilliiillii^^nm … It has been stated above, that the near end of the crown-bars isat^firsttemporarily supported or propped from the square timbers in the shafts; itmust however be observed, that, by so doing, a great weight is thrown uponthe square timbers in addition to that of the brickwork of the shaft, which…
Architecture · Civil engineering · Science
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