‹‹‹ Vitr. 4.2.2 | Table of Contents | Vitr. 4.2.4 ›››
3Others, in subsequent works, suffered the rafters’ feet above each triglyph, to run over, and hollowed out the projecting inferior surface. Thus, from the arrangement of beams, arose the invention of triglyphs; and, from the projection of the rafters, the use of mutuli under the corona. On which latter account it is observable, that in works of stone and marble the carving of the mutuli is inclined, in imitation of the feet of rafters, whose slope is necessary to carry off the water. Hence we have the imitation of the earliest works to account for the Doric triglyph and mutulus,
3Later, others in other buildings allowed the projecting principal rafters to run out till they were flush with the triglyphs, and then formed their projections into simae. From that practice, like the triglyphs from the arrangement of the tie-beams, the system of mutules under the coronae was devised from the projections of the principal rafters. Hence generally, in buildings of stone and marble, the mutules are carved with a downward slant, in imitation of the principal rafters. For these necessarily have a slanting and projecting position to let the water drip down. The scheme of triglyphs and mutules in Doric buildings was, therefore, the imitative device that I have described.