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against leakage. Open channels of granolithic will receive the rain water from the roofs and cast iron down pipes of large area will convey it on the face of the inner wall of the Collonnade to the underground drains (See para: 14 below)
13. It is proposed to use dressed granite externally throughout, and granite ashlar for the four great piers which carry the central dome. The internal walls and the backing of the external walls are proposed to be of brick. It is said that the best native bricks available come from Canton and that they are not very good. In the absence of exact information about them and their resistance to crushing it is assumed that they are sufficient for the foundations and interior walls. But where they serve as backing to granite faced walls it is important that the bricks should be hard and it is important that those locally made are not sufficient. In that case special bricks for the outer walls should perhaps be imported unless their cost would be equal to granite in which case it might be as well to construct the whole of the outer walls of granite which is "of excellent quality and plentiful in the Colony" and cheaply worked.
14. The material for the covering of the Dome is a question which has been very carefully considered and it is proposed to use thin slabs of granolithic for the purpose cast tapering with a nib on the upper edge to fit over the steel purlins and having converging lines of semicircular ribs to cover the cross joints. Such slabs are cast with
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