CHAPTER XIII¶
On the Intervals Between One Triglyph and Another.
What we have just said concerning the spacing of columns applies equally to the spacing of the triglyphs (tigrafi), which are placed near the summit of buildings upon the frieze above the epistyle (architrave):
Alignment and Spacing of Triglyphs
Every triglyph must be centered directly over the axis of the column beneath it (and with corresponding intervals over the intercolumniations), so that the upper order answers visually and structurally to the columns below.
Thus if the intercolumniation (tetrante) of the columns is \(1\frac{1}{2}\), \(2\), or \(2\frac{1}{2}\) column thicknesses, the spacing of the triglyphs is governed accordingly.
And in no way does Vitruvius commend an unreinforced stone span of 3 column thicknesses (diastyle), because under so wide an interval stone epistyles crack and break of their own weight, as you will hear immediately in the next chapter!