MEASUREMENT or MASONRY. The method of determining the quantity of masonry in a structure is frequently governed by trade rules or local custom, and these vary greatly with locality. Masons have voluminous and arbitrary rules for the measurement of masonry; for example, the masons and stone-cutters of Boston at one time adopted a code of thirty-six complicated rules for the measurement of hammer-dressed granite. As an example of the indefiniteness and arbitrariness of all such rules, we quote the follow ing, which are said to be customary in Pennsylvania: "All openings less than 3 feet wide are counted solid. All openings more than 3 feet wide are taken out, but 18 inches is added to the running measurement for every jamb built. Arches are counted solid from the spring of the arch, and nothing allowed for arching. The corners of buildings are measured twice (that is, the masonry in the corner is counted in each wall). Pillars less than 3 feet square are counted on three sides as lineal measurement, which is multiplied by the fourth side and by the depth; if more than 3 feet, the two opposite sides are taken, and to each side 18 inches for each jamb is added to the lineal measurement thereof, and the whole multiplied by the smaller side and by the depth." A well-established custom has all the force of law, unless due notice is given to the contrary. The more definite, and therefore the better, method is to measure the exact solid contents of the masonry, and pay accordingly. In "net measurement" all openings
are deducted; in "gross measurement" no openings are deducted.
The quantity of masonry is usually expressed . in cubic yards. The perch is occasionally employed for this purpose; but since the supposed contents of a perch vary from 16 to 25 cubic feet, the term is very properly falling into disuse. The contents of a masonry structure are obtained by measuring to the neat lines of the design. If a wall is built thicker than specified, no allowance is made for the masonry outside of the limiting lines of the design; but if the masonry does not extend to the neat lines a deduction is made for the amount it falls short. Of course a reasonable working allowance must be made when determining whether the dimensions of the masonry meet the specifications or not.
In engineering construction it is a nearly uniform custom to measure all masonry in cubic yards; but in architectural construc tion it is customary to measure water-tables, string-courses, etc., by the lineal foot, and window-sills, lintels, etc., by the square foot. In engineering, all dressed or cut-stone work, such as copings, bridge seats, cornices, water-tables, etc., is paid for in cubic yards, with an additional price per square foot for the surfaces that are dressed.