Cut a shaft with sixteen shallow flutes or facets, give it a square abacus and a low round base: the “proto-Doric” column of the Middle Kingdom rock tombs at Beni Hasan.
Rules · Pediments · Ornament · Proportion
Acroteria
On the angles of a pediment set acroteria as high as half the tympanum, and on its apex one an eighth higher.
side acroteria = ½ tympanum height; middle = side × 9⁄8
The Greeks carved them as palmettes or figures; the Romans and Palladio stood statues on them.
Related rules
An arch pushes outward on its supports as well as down. For the same load and span the horizontal push grows as the rise falls: halve the rise and you roughly double the thrust.
H ≈ w·s² ⁄ 8f (uniform load w per metre, span s, rise f)
To unify a façade of two or more storeys, run a single order of pilasters or columns through all of them, from the base to the main cornice.
Divide the inside of a dome into coffers that shrink in step with the meridians as they rise, so that their perspective deepens the dome and draws the eye to the light of the lantern.
Proportion every step so that twice its height plus its depth equals the length of a natural pace on the level: two feet, or 24 pouces.
2 r + g = 24 pouces ≈ 65 cm (modern practice: 60–66 cm)
Hold that the beauty of the orders comes from fixed proportions that please by nature, as consonances do in music; where the ancients differ, the differences answer to circumstances such as distance and height.
Cite this page Chris Paton, “Acroteria”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/acroteria. Text, drawings and models licensed under CC BY-NC 4.0.