To find fixed divisors for bringing the answer into feet or of a standard thickness, without multiplying the superficies by the number of half bricks, &c.

RULE.

Divide three, the number of half bricks in 11, by the number of half bricks in the thickness, the quotient will be a divisor, which will give the answer in feet. Or if a divisor is sought for, that will bring the answer in rods at once, multiply 272 by the divisor found for feet, and the product will be a divisor for rods; as in the following

Application of the above Table.

Multiply the length of the given wall by the breadth, o serve the number of half bricks it is in thickness; and oppcsite thereto will be found in the second column the divisor to reduce it to feet. ana in the third column the divi sor for rods. Thus in the above example 72,5 × by 19,25= 1395,625.

And 1395,625÷2727-5117+ the number of feet in standard measure.

And 1395,625÷74,18-18,8+ the number of rods

Or, by the Carpenters' Rule

As the tabular divisor, against the thickness of the wall is to the length of the wall :: so is the breadth : to the

content.

As 74,18 on B: 72,5 on A :: 19,25 cn B: 182 on A. Ans.

To find the dimensions of a building, measure half around on the outside, and half on the inside, for the whole length of the wall; this length being multiplied by the height gives the superficies. All the vacuities, such as doors, windows, window-backs, &c. must be deducted, for materials; but for workmanship alone no deductions are to be made, and the measurement is usually taken altogether on the outside. This is done in consideration of the trouble of the returns or angles. There are also some other allowances, such as double measure for feathered gable ends, &c.

2. How many yards and rods of standard thickness are contained in a brick wall, whose length is 57 feet 3 inches, and height 24 feet 6 inches; the wall being 24 bricks thick? Ans. 259,74 yards, or 8,58+ rods.

3. If a wall be 245 feet 9 inches long, 16 feet 6 inches high, and 2 bricks thick; how many rods of brick work are contained therein, when reduced to standard thickness? Ans. 24 rods 3 quarters 24 feet.

4. A triangle gable end is raised to the heis of 15 feet above the wall of a house, whose width is 45 feet and the thickness of the wall 2 bricks; required the conten in rods at standard thickness? Ans. 2 rods 18 feet.

Chimneys by some are measured as if they were solid, deducting only the vacuity from the hearth to the mantle, on account of their trouble.

But by others, they are girt or measured round for their breadth, and the height of their story, taking the depth of the jambs for their thickness. And in this case no deduction is made for the vacuity from the floor to the mantle-tree, because of the gathering of the breast and wings, to make "oom for the hearth in the next story.

If the chimney back be a party wall, and the wall be measured by itself, then the depth of the two jambs and length of the breast is to be taken for the length, and the height of the story for the breadth, at the same thickness with the jambs.

Those parts of the chimney-shaft which appear above the roof are to be girt with a line round about the icast place of them for the length, and take the height for the breadth; and if they are 4 inches thick, they are to be accounted, as one brick work, and if they are 9 inches thick, they are to be taken for 1 brick work, on account of the trouble of plastering and scaffolding.

It is customary in most places to allow double measure for chimneys.

SECTION 6.

OF MASONS' WORK.

MASONS' work is measured sometimes by the foot solid, sometimes by the foot superficial, and sometimes by the foot in length. It is also measured by the yard, and mostly by the rod or perch, which is 16 feet in length, 18 inches in breadth, and 12 inches in depth.

Walls are measured by the perch; columns, blocks of stone, or marble, &c. by the cubic foot; and pavements, slabs, chimney-pieces, &c. by the superficial or square foot.

Cubic, or solid measure, is always used for materials, but square measure generally for workmanship.

In solid measure, the true length, breadth and thickness are taken and multiplied into each other for the content.

In superficial measure, the length and breadth of every part of the projection, which is seen without the general upright face of the building, is taken for the content.

EXAMPLES.

1. If a wall be 97 feet 5 inches long, 18 feet 3 inches high, and 2 feet 3 inches thick, how many solid feet, and perches, are contained therein?

2 How many solid feet and perches are contained in a wall 53 feet 6 inches long, 12 feet 3 inches high, and 2 feet thick? Ans. 1310,75 feet, and 52,9595 rods.

3. If a wall be 107 feet 9 inches long, and 20 feet 6 inches high, how many superficial feet are contained therein ? Ans. 2208 feet 10 inches.

4. If a wall be 112 feet 3 inches long, and 16 feet 6 inches high, how many superficial rods, each 63 square feet, are contained therein? Ans. 29 rods 25 feet.

5. What is a marble slab worth, whose length is 5 feet 7 inches, and breadth 1 foot 10 inches, at 80 cents per foot superficial? Ans. 8 dolls. 19 cts.

SECTION 7.

OF PLASTERERS' WORK.

PLASTERERS' WORK is principally of two kinds, viz.first, plastering upon laths, called ceiling; and second, plastering upon walls, or partitions made of framed timber, called rendering, which are measured separately.

Plasterers' work is usually measured by the yard square, consisting of 9 square feet; sometimes it is measured by tho square foot, and sometimes by the square of 100 feet.

Enriched mouldings, cornices, &c. are rated by running, or lineal measure. In arches, the girt round them multiplied by the length, is taken for the superficies.

Deductions are to be made for doors, chimneys, windows, and other large vacuities. But when the windows, or other openings, are small, they are seldoın deducted, as the plasterea returns at the top and sides are allowed to compensate for the vacuity.

Whitewashing and coloring are measured in the same manner as plastering.

EXAMPLES.

1. If a ceiling be 59 feet 9 inches long, and 24 feet 6 inches broad, how many superficial yards of 9 square feet does it contain?