4and not, as some have erroneously said, from the circumstance of triglyphs being introduced as windows; which could not be the case, inasmuch as they are placed on external angles, and immediately over columns, in both which situations windows would be absurd, in the highest degree, for the tye at the angles of buildings would be entirely destroyed, if occupied by windows; and therefore the dentils of the Ionic orders might as properly be seen to occupy the places of windows, if the spaces occupied by triglyphs have an origin of such a nature. The intervals, moreover, between dentils, as well as those between triglyphs, are called metopæ. Besides, the Greeks, by the word ὄπαι, signify the beds of the beams, which we call cava columbaria: thus the space between two beams obtained the name of a metopa.
4It cannot be that the triglyphs represent windows, as some have erroneously said, since the triglyphs are placed at the corners and over the middle of columns—places where, from the nature of the case, there can be no windows at all. For buildings are wholly disconnected at the corners if openings for windows are left at those points. Again, if we are to suppose that there were open windows where the triglyphs now stand, it will follow, on the same principle, that the dentils of the Ionic order have likewise taken the places of windows. For the term “metope” is used of the intervals between dentils as well as of those between triglyphs. The Greeks call the seats of tie-beams and rafters ὁπαἱ, while our people call these cavities columbaria (dovecotes). Hence, the space between the tie-beams, being the space between two “opae,” was named by them μετὁπη.