London : Longman, Rees, Orme, Brown, Green, and Longman · leaf 425
high, but with fourcourses of masonry over the crown of the arch, just balanceswith 6 lb. on the top. (See diagram fig. 159. a ef b.) Thesefour courses of masonry, again, lender the pier a g of equalstrength to the double pier a dg. Exper. 10. The same segment of arch and span as the pre-ceding… … of the pier 4 in. by 4 in., as shown in the diagram Jig. 160., bythe letters a d c b. This arch just balances with 2 lb. on the topof the crown. Exper. 12. The same arch and pier as experiment 10., andof the same height, but having four courses of masonry overthe crown (see diagram Jig. 160. a ejb)…
Architecture
Internet Archive · Public Domain Mark 1.0. Free to use for anything.
