MASONRY, 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 unbewed 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.
Bound masonry, is that in which the stones were placed one over another, like tiles; the joints of their beds being level, and the mounters perpendiculars, 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.
Greek masonry, according to Vitruvius, is that where after we have laid two stones, each of which makes a
Masonry. 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.
Masonry by equal courses, called by the ancients isodomum, differs in nothing from the bound masonry, but only in this, that its stones are not hewn.
Masonry by unequal courses, called pseudisodomum, 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.
Masonry filled up in the middle, is likewise made of unhewn stones, and by courses: but the stones are only set in order as to the courses.
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 in together: after this the stones of one course are bound to those of another course with iron cramps fastened with melted lead.
All the kinds of masonry now in use may be reduced to these five, viz. bound masonry; that of brick work, where the bodies and projectures of the stones enclose square spaces or panneis, &c. set with bricks; that de moilon, 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.