These mouldings are common to both Grecian and Roman archi tecture, but besides being more profusely applied in the latter style they have this marked difference, that in Roman architecture the curved mouldings, whether simple or compound, are described by quarter circles, whereas in Greek they describe other curves obtained from conic sections, and are therefore not only more elegant in their contour, but susceptible of far greater variety. Some of them are also occasionally undercut, that is, hollowed out below and behind, whereby, while a greater depth of shadow is obtained, a greater sharpness of lines and lightness of form are produced. Of this kind is what is now distinguished by the name of the bird's-beak moulding, because its section produces an outline very much resembling that of the hooked upper and lower mandible in the beaks of some birds.
In Gothic mouldings, undercutting is very common, and hollows or recesses more or less deep are frequently numerous in the profiles of mouldings in that style. The mouldings are also for the most part produced by splayed or bevelled surfaces, that is, slanting or turned obliquely from the or general plane where they occur. In that style the mouldings are so numerous, and the profiles produced by them so complex, as to render it impossible to describe or charac terise them further. They are however of the utmost importance, both as adding greatly to the effect of buildings, and as assisting in the discrimination of the several styles or periods to which the buildings belong, and therefore require to be well studied and perfectly under stood, for which purpose such works of detail as Pugin's Gothic Specimens,' and Gothic Examples ; ' Paley's' Manual of Gothic Mould ink &c., may be reonunnencled : the 1inprofessional reader will pro
bably find sufficient information on the subject in Palefa Manual of Gothic Architecture; Illexam's Principles of Gothic Architecture,' or any of the other accepted guides to the study of Gothic architecture; acv also the articles GOTHIC ARCHITECTURE, and NORMAN ARCHITEC TURE. One circumstance however which ought to be mentioned is that the mouldings all recede within the face of the wall (like theme of panels], except labels, hood-mouldings, and others, that come under the general denomination of weather mouldings, because made to pro. ject instead of recede, and therefore more exposed to rain and weather.
In regard to Grecian mouldings, it remains to be observed that many of those which are uncured, and therefore supposed to have been quite plain, were with some ornamental pattern, and that not uufrequently in the most brilliant colours. But this mode of decoration is treated more at length in the article Posrcintoxr.