General Rules of Architecture

FOURTH BOOK ###

The ancients used various ways of bondingoriginal: "ligamenti"; the structural interlocking of masonry units this rusticated workoriginal: "opera rustica"; masonry featuring rough, textured surfaces and deep-set joints, often used for the ground floors of palaces or for fortifications, as is shown demonstrated below; from which invention the Architect may adapt to various things, according to the circumstances that may occur. Its measurement shall be such that the opening is a perfect square. The solid pier between one opening and the other should be one-quarter smaller than that opening. The lintel, called the Architrave, should be one-fourth the height of the opening, and it should be made of wedgesoriginal: "cunei"; these are wedge-shaped stones, also known as voussoirs, which distribute weight outward that converge at the center, in an odd number. And thus, above it, a semicircle shall be drawn, divided into nine equal parts, and all lines shall be drawn to its center, and its wedges formed, with the three pieces with the band above placed between them: and in this way the work will be very strong and perpetual. But so that the wedges of the architrave stay firmer, it will be necessary to fill the semicircle with brickworkoriginal: "opera lateritia"; literally "baked stone" (pietra cotta), and for greater ornament, it can be made of reticulated workoriginal: "opera reticulata"; a Roman masonry technique using diamond-shaped tuff blocks that create a net-like appearance, as the ancients used. And in Rome, at the church of Saints Cosmas and Damian, one can still see similar bonds that remain very strong, even though they are extremely ancient.