"A keystone is the architectural piece at the crown of a vault or arch which marks its apex, locking the other pieces into position.This makes a keystone very important structurally. In an arch, the keystone is usually larger than the voussoirs that make up the arch and may serve primarily an aesthetic purpose. Some say that a keystone is not as important structurally as the [voussoirs], since the removal of any of the voussoirs would cause the arch to collapse but this is not necessarily true of the keystone.Old keystones, crucial in medieval buildings, can decay due to vibration, a condition known as bald arch.In a vault, keystones may mark the intersections of tracery". $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ $$$$$$$$$ http://www.keystonss.webs.com/ $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ $$$$$$$$$ " JOIN OUR COMPANY SURELY YOU WILL GET MANY DETAILS ABOUT KEYSTONE" *************************************************************************************** http://www.cuteonly.com/?a_aid=0a98fa8b&a_bid=d8c19bfc *************************************************************************************** --~--~---------~--~----~------------~-------~--~----~ Fun on the World -~----------~----~----~----~------~----~------~--~---
