Page:An Elementary History of Art.djvu/32

 2 Introduction. A building may be said to have character when its form and proportions express the purpose for which it is intended. The effect may be improved by well-designed ornamentation. Its form and style depend in a great measure upon the mode of covering openings, such as doors and windows, and forming roofs ; and the building is of course much affected by the nature of the material which is chosen. Rock-hewn caves, such as those of the Hindus, Egyptians, Etruscans, and other ancient peoples, are monoliths (of one stone), even when the cave is large and divided into different parts by props of stone left standing. When an important building is to be erected, the first course is to define its form by walls, or sometimes by pillars, which last may consist either of a succession of stones of similar size, or of a single mass. The openings between the pillars and the doorways and the other openings in the walls are then spanned by horizontal stones (lintels). This was the plan adopted by the Egyptians and Greeks. Wooden lintels were sometimes employed instead of stone. The nature of the material necessarily restricts, within certain limits, the dimensions of the openings or spaces which are to be covered with lintels. Wider openings can be covered if the stone lintel is replaced by the arch, which is formed of stones cut wedge-shaped (voussoirs) and cemented together with mortar. The arch, of whatever kind — semicircular, pointed, or horseshoe — supplanted stone lintels, and the vault took the place of the flat roof. These were the methods of roofing adopted by the Romans, and by different nations in the early Christian and middle ages, and at the time of the Renaissance.