‹‹‹ Vitr. 3.5.4 | Table of Contents | Vitr. 3.5.6 ›››
5The shafts of the columns being fixed, the proportions of the capitals are thus adjusted: if pillowed, as in the Ionic, they must be so formed that the length and breadth of the abacus be equal to the diameter of the lower part of the column and one eighteenth more, and the height of the whole, including the volutes, half a diameter. The face of the volutes is to recede within the extreme projection of the abacus one thirty-ninth part of the width of the abacus. Having set out these points on the listel of the abacus at the four angles, let fall vertical lines. These are called catheti. The whole height of the capital is now to be divided into nine parts and a half, whereof one part and a half is the height of the abacus, and the remaining eight are for the eye of the volute.
5The shafts of the columns having been erected, the rule for the capitals will be as follows. If they are to be cushion-shaped, they should be so proportioned that the abacus is in length and breadth equivalent to the thickness of the shaft at its bottom plus one eighteenth thereof, and the height of the capital, including the volutes, one half of that amount. The faces of the volutes must recede from the edge of the abacus inwards by one and a half eighteenths of that same amount. Then, the height of the capital is to be divided into nine and a half parts, and down along the abacus on the four sides of the volutes, down along the fillet at the edge of the abacus, lines called “catheti” are to be let fall. Then, of the nine and a half parts let one and a half be reserved for the height of the abacus, and let the other eight be used for the volutes.