London : Longman, Rees, Orme, Brown, Green, and Longman · leaf 136
proved to be so very strong,I determined upon finding out its weakest parts; and, by tryingdiflercnt weights, I discovered them to be at the points d and <r,just half way between the crown (c) and the base (a b). Whenthe weight of 6 lb. was placed at 6, the arch was balanced with Principles of… … arch asjig. 23., being composed of twelve voussoirs. Betweenc and b some wooden bricks were placed, as represented by c kb, which were built up regularly. At the point e, which is pei--pendicularly over the weakest part of the arch on this side, someweights were placed, and the arch was found just…
Architecture
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