A Treatise Containing the Practical Part of Fortification - In Four Parts #247710

But the greateft nfe of elliptic arches appears to be in the building of bridges, and they feem ih deed to be the only ones that are proper for fuch works: for when the arches are of a great width, the circular form raifes the middle of the bridge too high above the ends, whereby the draught of heavy carriages becomes very great, neither does it appear 12) well to the eye, and requires much more mafonry than is necefiiu'y; to which may be added, that this great weight requires larger foundations for the piers, and often canfes them to fink when the foil underneath is not very hard and felid, as experience has fufiiciently fhewn.