General Rules of Architecture

VII

B

On the left is a vertical elevation of a column's capital and its base. The capital is labeled with letters A through F. The top of the shaft is marked G and the bottom H. The base consists of sections I, K, and L. Below this elevation is a plan view diagram showing concentric circles labeled M, N, and O, illustrating the different diameters and projections of the column components.

A, Plinth, called the abacus, or cymatium. original: "Plintho, detto abaco, o cimasa." These terms refer to the flat, square slab forming the topmost part of the capital.
B, Echinus, called the ovolo. original: "Echino, detto Vuouolo." A rounded, convex molding; the name 'ovolo' comes from its egg-like shape. +
C, Annulet, called the small square, or regula. original: "Anulo, detto quadretto, o regolo." A small, flat decorative band. +
D, Hypotrachilium, called the neck-frieze. original: "Hipotrachelio, detto fregio." The part of the column that transitions between the shaft and the capital. +
E, Astragal, called the bead-molding. original: "Astragalo, detto Tondino." A small, semi-circular molding. +
F, Small square, called the collarino. original: "Quadretto, detto Collarino." The necking or 'little collar' of the column. +
G, Upper Shaft, that is, the thickness of the column at the top part.

H, Lower Shaft, that is, the thickness of the column at the bottom part.
I, Small square, called the small step; others call it a listel, others a band. original: "Quadretto, detto Gradetto, altri lo dicono Listello, altri cinta."
K, Torus, called the staff; others call it by various names. original: "Toro detto bastone." A large, semi-circular convex molding at the base of the column.
L, Plinth, called the block. original: "Plintho, detto Zocco." The square or circular lowest part of the base.

M, Projection of the base, called the overhang. original: "Proiettura de la base detta sporto." This indicates how far the base moldings extend beyond the column shaft.
N, Lower shaft of the column, that is, its thickness at the bottom.
O, Upper shaft of the column, that is, its thickness at the top.

On the right is a vertical diagram of a column shaft showing its tapering (entasis). The shaft is divided into four numbered sections (1, 2, 3, 4). At the bottom of the shaft, a cross-section or profile of the base is shown with four horizontal subdivisions also numbered 1 through 4.