To masonry belong all sorts of stone-work; and the measure made use of is a foot, either superficial or solid. Walls, columns, blocks of stone or marble, etc., are measured by the cubic foot; and pavements, slabs, chimney-pieces, etc, by the superficial or square foot. Cubic or solid measure is used for the materials, and square measure for the workmanship. In the solid measure, the true length, breadth and thickness, are taken, and multiplied continually together. In the superficial, there must be taken the length and breadth of every part of the projection, which is seen without the general upright face of the building.

Example. - In a chimney-piece, suppose the length of the mantel and slab each 4 feet 6 inches; breadth of both together 3 feet 2 inches; length of each jamb 4 feet 4 inches; breadth of both together 1 foot 9 inches. Required the superficial content. - Ans. 21 feet 10 inches.

4 ft,

6 in,

X

3 ft.

a

in.

=

14 ft.

3 in.

21 feet 10 inches.

4"

4 "

X

1"

9

"

=

7 "

7"

Rubble Walls (unhewn stone) are commonly measured by the perch,which is 16 feet long, 1 fool deep, and 1 fool thick, equivalent to 24 cubic feel. 25 cubic feet is sometimes allowed to the perch, in measuring stone before it is laid, and 22 after it is laid in the wall. This species of work is of two kinds, coursed and uncoursed; in the former the stones are gauged and dressed by the hammer, and the masonry laid in horizontal courses, but not necessarily confined to the same height. The uncoursed rubble wall is formed by laying the stones in the wall as they come to hand, without any previous gauging or working.

27 cubic feet of mortar require for its preparation, 9 bushels of lime and 1 cubic foot of sand.

Lime and sand lessen about one-third in bulk when made into mortar; likewise cement and sand.

Lime, or cement and sand, to make mortar, require as much water as is equal to one-third of their bulk.

AU sandstones ought to be placed on their natural beds; from inattention to this circumstance, the stones often split off at the joints, and the position of the lamina much sooner admits of the destructive action of air and water.

The heaviest stones are most suited for docks and harbors, breakwaters to bridges, etc.

Granite is the most durable species of stone yet known for the purposes of building. It varies in weight according to quality; the heaviest is the most durable.