Page:Ware - The American Vignola, 1920.djvu/12

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A beam that spans the space between two piers or columns, or between a pier or column and a wall, is called an Architrave, or Epistyle. Above it, between the Architrave and the Cornice, there is generally a little strip of wall called the Frieze. Architrave, Frieze, and Cornice constitute the Entablature. A series of columns is called a Colonnade, Fig. 12. The spaces between piers or columns are sometimes spanned by Arches', a series of which is called an Arcade, Fig. 13.

The space between two parallel walls is sometimes covered by a sort of continuous arch, called a Vault, instead of by a floor or roof, Fig. 14.

The under surface of a beam or architrave is called its Soffit, and the same name is used also for the Intrados, or under surface of an arch or vault. The upper surface, or back of an arch, is called the Extrados, and the triangular space of wall above is called a Spandrel.

The Wall, the Pier, and the Column, with or without a Pedestal, constitute the chief supporting members; the Frieze and Cornice, with the roof that rests upon them, constitute the chief part of the load they carry. The Architrave, the Arches, and the Spandrels form part of the load, relatively to what is below them, but are supporting members relatively to what is above them.

Besides being valuable as a shelter, a building may be in itself a noble and delightful object, and architects are builders who, by giving a building good proportions and fine details, and by employing beautiful materials, make it valuable on its own account, independently of its uses. Their chief instruments in this work are Drawings, both of the whole building and, on a larger scale, of the different features which compose it and of their details, which are often drawn full size. These drawings comprise Plans, Sections, Elevations, and Perspective Views, Fig. 15. They serve to explain the intention of the architects to their clients and to their workmen.