Page:Charles Moore--Development and Character of Gothic Architecture.djvu/30

6  These conceptions of the nature of Gothic are inadequate. It is not by the consideration of such structurally unessential features that an understanding of the subject can be reached. By such approach it would be impossible to discover the principles of any art. The principles to be considered are constructive principles. They determine the nature and govern the entire fabric of every art. In architecture they are pre-eminently fundamental. In architecture mere forms apart from their functional offices and relations are not enough to enable us to apprehend the distinctive characteristics of styles. Semicircular forms instead of straight beams may, for instance, be used to bridge the spaces between the upright supports of a building without a result which would constitute between a building employing the latter form and one employing the former, a difference of architectural style. For an arch may be cut out of a single stone, as at A, Fig. 1, as it frequently is in the buildings of Central Syria, where the constructive principle is, of course, that of the plain lintel, as at B,  Fig. 1.  Or the arch may be built up in horizontal courses of small stones, and thus be what is known as the offset arch (Fig. 2), like the gate of Ephesus, which is still on the principle of the lintel. It is not until the arch is constructed of separate stones cut into the shapes of voussoirs, when it comes to exert a lateral thrust which requires to be met by some opposing force, that we have a new