The shaft of the Doric column may be plain or channelled with vertical grooves called flutes. There are twenty of these flutes round the circumference. On plan they are shallow, and may be formed of arcs of a third of a circle. The curves meet without intervening fillets. The flutes are finished off in segmental curves at the top and bottom, leaving a small plain space below the necking and above the base.
The Ionic and Corinthian columns may have plain or decorated shafts. If decorated they have twenty-four flutes round the circumference. These are semi-circular on plan, and are spaced with fillets between them.
The Capital
The Capital is the culminating feature of the column in which horizontal lines predominate in æsthetic contrast to the vertical lines of the shaft. In all the orders there is some form of crowning block or moulding known as the abacus.[A]
[A] Though the proportions given are approximately accurate for general division, it will be found necessary in detailing to adopt a more intimate system of measurement. In the following diagrams the diameter is divided into 36 parts, which are expressed in figures, giving heights, etc., of the various features.
Doric Capital
The Doric abacus consists of a rectangular slab, square on plan, which in detail consists of a fillet and reversa moulding surmounting a facia. Its extreme width is one and a half times the upper diameter. The square abacus is supported by an ovolo, which is circular on plan, and is connected with the necking by three small fillets.
