This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
The Portico or Atrium was Built in 1629-67 by Lorenzo Bernini. The Dome of St. Peter's was Designed Principally by Michelangelo.
The "Tasteless Facade" (Hamlin) was Designed by C. Maderna in 1600.
19. Columns are connected to one another overhead by a timber or stone called the architrave. Generally there is above the architrave a plain space, called the frieze, lining with the neck of the column below, and above the frieze a projecting mass that completes the whole and is called the cornice. The architrave, frieze, and cornice taken together are called the entablature. A column with an entablature constitute an Order of Architecture.
20. Sometimes an Order of Architecture is set upon a mass of a certain height which is called the pedestal. The Pedestal often has a base, and a cornice or crowning member called a cap. The space between the base and the cap is called the die of the pedestal.
22. For the sake of elegance and lightness, the shafts of columns and pilasters are generally made smaller at the top than at the bottom. This prevents the shafts from appearing clumsy. They do not, however, taper all the way from the base upward, but only from a point one-third the height of the shaft above the base. Above this point the outline of a column or pilaster shaft is a gentle tapering curve. This swelling curve or taper is called the "entasis" of the column.
23. It must be noted that the diminution of the pilaster is much less than that of the column, and that in some cases the pilaster is of the same width at the neck as at the base. As specifically shown hereafter, there are certain relations between the necks and bases of columns and pilasters of each of the Orders. Occasionally, where a pilaster is used alone upon the corner of a building and not in immediate association with a tapered column, the pilaster shaft is, for obvious reasons, of the same width at the neck as at the base. See plates XXVII and XXVIII.
24. When square pillars carry vaults or arches instead of lintels, the pillars are called piers (Fig. 4). If a support is square or oblong in plan, and its thickness in relation to its height is considerably more than the thickness of a column, it is called a pier even though it carries a lintel. When a pier is topped by a projecting stone or series of mouldings from which an arch springs, this projection is called the impost, and the projecting band or border that is often placed around the edge of the arch is called an archivolt. Piers generally rest upon a base or plinth.
25. An arch is a support constructed of separate stones, units, or voussoirs, with its center higher than its two ends, and of an outline which is, in part or entirely, a circle, or a curve laid out from one or more centers. A vault is a continuous arch roofing over a room or passage, whose length is considerably greater than its width. A series of arches in succession opening upon the space covered by a vault, may be called an arcade.
- 26. Note the distinction between the lintel, a single horizontal member carrying a superimposed weight to the piers by its own strength, and the arch, a curved construction which carries a superincumbent weight by transferring its load to the piers or supports from which it springs, but unlike the lintel, adding a certain lateral "thrust" which the supports must resist.