ro8 A History of Art in Ancient Egypt. stones which form the roof are too small to bridge over the whole of the space comprised within two walls, they must be made to rest upon intermediate supports ; and this necessity springs up in every building of any importance. This very elementary com- bination fulfils all the re- quirements of circulation. The number of supports depends upon the number of rows of the flat stones which form the roof. They are sometimes multiplied to such an extent that they remind us of that planting arrange- ment in our gardens which we call a quincunx. We cannot, however, affirm that the number of supports is invariably decided by the length of the architraves, or of the roof- ing stones. Some very long monoliths are supported at regular Fk;. 70. — Dcuble-faccd wall. Figs. 71, 72. — Elements of the portico. intervals, lest they should break with their own weight or with that put upon them. The walls, architraves, and vertical supports are always far stronger than the mere weight of the roof would require.
