in general, a branch of architecture, consisting in the art of hewing or squaring stones, and cutting them level or perpendicular, for the uses of building: but, in a more limited sense, masonry is the art of assembling and joining stones together with mortar.

Hence arise as many different kinds of masonry, as there are different forms and manners for laying or joining stones. Vitruvius mentions several kinds of masonry used among the ancients: three of hewed stone, viz. that in form of a net, that in binding, and that called the Greek masonry; and three of unhewn stones, viz. that of an equal course, that of an unequal course, and that filled up in the middle; and the seventh was a composition of all the rest.

Net-masonry, called by Vitruvius reticulatum, from its resemblance to the meshes of a net, consists of stones squared in their courses, and so disposed as that their joints go obliquely; and their diagonals are the one perpendicular, and the other level. This is the most agreeable masonry to the eye, but it is very apt to crack. See no 1.

Bound masonry, that in which the stones were placed one over another, like tiles; the joints of their beds being level, and the munters perpendicular, so that the joint that mounts and separates two stones, always falls directly over the middle of the stone below. This is less beautiful than the net-work; but it is more solid and durable. See no 2.

Greek masonry, according to Vitruvius, is that where after we have laid two stones, each of which makes a course, another is laid at the end, which makes two courses, and the same order is observed throughout the building; this may be called double-binding, in regard the binding is not only of stones of the same course with one another, but likewise of one course with another course. See no 3.

Masonry by equal courses, called by the ancients pseudodomum, differs in nothing from the bound masonry, but only in this, that its stones are not hewn. See no 4.

Masonry by unequal courses, called pseudodomum, is also made of unhewn stones, and laid in bound work; but then they are not of the same thickness, nor is there any equality observed excepting in the several courses, the courses themselves being unequal to each other. See no 5.

Masonry filled up in the middle, is likewise made unhewn stones, and by courses; but the stones are only set in order as to the courses. See no 9. A, the courses; B, the parts filled up; C, a coat of plaster.

Compound masonry is of Vitruvius's proposing, so called as being formed of all the rest. In this the courses are of hewed stone; and the middle being left void, is filled up with mortar and pebbles thrown together: after this the stones of one course are bound to those of another course with cramp-irons fastened with melted lead. See no 7. E, the stones cramped; F, the cramps; G, the middle part filled up.—No 8. represents another sort of compound masonry, the middle of which is stone, and the edges boards.

All the kinds of masonry now in use may be reduced to these five, viz. bound masonry; that of brickwork, where the bodies and projections of the stones inclose square spaces or panels, &c. set with bricks; that de moillon, or small work, where the courses are equal, well squared, and their edges or beds rusticated; that where the courses are unequal; and that filled up in the middle with little stones and mortar.