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OF ARTIFICERS' WORKS
I. OF THE CARPENTER'S OR SLIDING RULE.
THE Carpenter's or Sliding Rule, is an instrument much used in measuring of timber and artificers' works, both for taking the dimensions, and computing the contents.
The instrument consists of two equal pieces, each a foot in length, which are connected together by a folding joint.
One side or face of the rule is divided into inches, and eighths, or half quarters. On the same face also are several plane scales, divided into 12th parts by diagonal lines; which are used in planning dimensions that are taken in feet and inches. The edge of the rule is commonly divided decimally, or into tenths; namely, each foot into ten equal parts, and each of these into ten parts again; so that by means of this last scale, dimensions are taken in feet, tenths and hundredths, and multiplied as common decimal numbers, which is the best way.
On the one part of the other face are four lines, marked A, B, C, D; the two middle ones, B and C, being on a slider, which runs in a groove made in the stock. The same numbers serve for both these two middle lines,—the one being above the numbers, and the other below.
These four lines are logarithmic ones, and the three A, B, C, which are all equal to one another, are double lines, as they proceed twice over from one to ten. The other or lowest line D, is a single one, proceeding from four to forty. It is also called the girt line, from its use in computing the contents of trees and timber; and upon it are marked WG at 17·15, and AG at 18-95, the wine and ale gauge points, to make this instrument serve the purpose of a gauging rule.
On the other part of this face, there is a table of the value of a load, 50 cubic feet of timber, at all prices, from sixpence to two shillings a foot.
When I at the beginning of any line is accounted 1, then the 1 in the middle will be 10, and the 10 at the end 100; but when 1 at the beginning is accounted 10, then the 1 in the middle is 100, and the 10 at the end 1000; and so on. And all the smaller divisions are altered proportionally.
ARTIFICERS Compute the contents of their works by several different measures;
Glazing and masonry by the foot;
Painting, plastering, paving, &c., by the yard, of 9 square feet;
Flooring, partitioning, roofing, tiling, &c., by the square of 100 square feet.
And brickwork, either by the yard of 9 square feet, or by the perch, or square rod or pole, containing 2724 square feet, or 304 square yards, being the square of the rod or pole of 161⁄2 feet of 51⁄2 yards long.
As this number 2724 is troublesome to divide by, the is often omitted in practice, and the content in feet divided only by the 272. But when the exact divisor 272 is to be used, it will be easier to multiply the feet by 4, and then divide successively by 9, 11, and 11. Also to divide square yards by 301, first multiply them by 4, and then divide twice by 11.
All works, whether superficial or solid, are computed by the rules proper to the figure of them, whether it be a triangle or rectangle, a parallelopiped or any other figure.
III. BRICKLAYERS' WORK.
BRICKWORK is estimated at the rate of a brick and a half thick. So that, if a wall be more or less than this standard thickness, it must be reduced to it, as follows:
Multiply the superficial content of the wall by the number of half bricks in the thickness, and divide the product by 3.
The dimensions of a building are usually taken by measuring half round on the outside and half round on the inside; the sum of these two gives the compass of the wall,-to be multiplied by the height, for the content of the materials.
Chimneys are by some measured as if they were solid, deducting only the vacuity from the hearth to the mantle, on account of the trouble of them.
And by others they are girt or measured round for their breadth, and the height of the story is their height, 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 room for the hearth in the next story.
To measure the chimney shafts, which appear above the building, girt them about with a line for the breadth, to multiply by their height. And account their thickness half a brick more than it really is, in consideration of the plastering and scaffolding,
All windows, doors, &c., are to be deducted out of the contents of the walls in which they are placed. But this deduction is made only with regard to materials; for the whole measure is taken for workmanship, and that all outside measure too, namely, measuring quite round the outside of the building, being 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.
Ex. I.-How many yards and rods of standard brick-work are in a wall whose length or compass is 57 feet 3 inches, and height 24 feet 6 inches; the walls being 2 bricks or 5 half bricks thick? Ans. 8 rods, 17 yards.
Ex. 11.-Required the content of a wall 62 feet 6 inches long, and 14 feet 8 inches high, and 23 bricks thick? Ans. 169-753 yards. on an end wall whose required the reduced Ans. 32.08 yards.
Ex. 1. A triangular gable is raised 17 feet high, length is 24 feet 9 inches, the thickness being two bricks; content?
Ex. IV. The end wall of a house is 28 feet 10 inches long, and 55 feet 8 inches high, to the eaves; 20 feet high is 24 bricks thick, other 20 feet high is 2 bricks thick, and the remaining 15 feet 8 inches is 1 brick thick; above which is a triangular gable, 1 brick thick, and which rises 42 courses of bricks, of which every 4 courses make a foot. What is the whole content in standard measure ? Ans. 253-626 yards.
IV. MASONS' WORK.
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, &c., are measured by the cubic foot; and pavements, slabs, chimney-pieces, &c., 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.
Ex, 1.-Required the solid content of a wall, 53 feet 6 inches long, 12 feet 3 inches high, and 2 feet thick ? Ans. 1310 feet.
Ex. 11.-What is the solid content of a wall, the length being 24 feet 3 inches, height 10 feet 9 inches, and 2 feet thick?
Ans. 521.375 feet.
Ex. III.-Required the value of a marble slab, at 8s. being 5 feet 7 inches, and breadth 1 foot 10 inches ?
Ex. Iv.—In a chimney-piece, suppose the
Length of the mantle and slab, each 4 feet 6 inches;
Ans. 21 feet, 10 inches.
Required the superficial content ?
per foot; the length Ans. £4, is. 101d.
V. CARPENTERS' AND JOINERS' WORK.
To this branch belongs all the wood-work of a house, such as flooring, partitioning, roofing, &c.
Large and plain articles are usually measured by the square foot or yard, &c., but enriched mouldings, and some other articles, are often estimated by running or lineal measures, and some things are rated by the piece.
In measuring of joists, it is to be observed, that only one of their dimensions is the same with that of the floor; for the other exceeds the length of the room by the thickness of the wall and of the same, because each end is let into the wall about of its thickness.
No deductions are made for hearths, on account of the additional trouble and waste of materials.
Partitions are measured from wall to wall for one dimension, and from floor to floor, as far as they extend, for the other.
No deduction is made for door-ways, on account of the trouble of framing them.
In measuring of joiners' work, the string is made to ply close to every part of the work over which it passes.
The measure for centering for cellars is found by making a string pass over the surface of the arch for the breadth, and taking the length of the cellar for the length; but in groin centering, it is usual to allow double measure, on account of their extraordinary trouble.
In roofing, the length of the house in the inside, together with of the thickness of one gable, is to be considered as the length; and the breadth is equal to double the length of a string which is stretched from the ridge down the rafter, and along the eaves-board, till it meets with the top of the wall.
For stair-cases, take the breadth of all the steps, by making a line ply close over them, from the top to the bottom, and multiply the length of this line by the length of a step, for the whole area. By the length of a step is meant the length of the front and the returns at the two ends; and by the breadth, is to be understood the girt of its two outer surfaces, or the tread and riser.
For the balustrade, take the whole length of the upper part of the hand-rail, and girt over its end till it meet the top of the newel post, for the length; and twice the length of the baluster upon the landing, with the girt of the hand-rail, for the breadth.
For wainscotting, take the compass of the room for the length; and the height from the floor to the ceiling, making the string ply close into all the mouldings, for the breadth.—Out of this must be made deductions for windows, doors, and chimneys, &c., but workmanship is counted for the whole, on account of the extraordinary trouble.
For doors, it is usual to allow for their thickness, by adding it into both the dimensions of length and breadth, and then multiply them together for the area. If the door be pannelled on both sides, take double its measure for the workmanship; but if the one side only be pannelled, take the area and its half for the workmanship.—For the surrounding architrave, gird it about the outermost parts for its length; and measure over it, as far as it can be seen when the door is open for the breadth.
Window-shutters, bases, &c., are measured in the same manner.
In the measuring of roofing for workmanship alone, holes for chimney shafts and skylights are generally deducted.
But in measuring for work and materials, they commonly measure in all skylights, luthern-lights, and holes for the chimney shafts, on account of their trouble and waste of materials.
Ex. 1.-Required the content of a floor 48 feet 6 inches long, and 24 feet 3 inches broad? Ans. 11 squares, 76 feet.
16 feet 6 inches broad, how Ans. 5 squares, 98 feet.
10 inches in length, and 10 Ans. 18-3972 squares.
Ex. II.—A floor being 36 feet 3 inches long, and many squares are in it?
Ex. III.-How many squares are there in 173 feet feet 7 inches height, of partitioning ?
10s. 6d. a square; the length
Ex. IV. What cost the roofing of a house at within the walls being 52 feet 8 inches, and the breadth 30 feet 6 inches,—— reckoning the roof of the flat? Ans. 12, 12s. 113d.
Ex. v. To how much, at 6s. per square yard, amounts the wainscotting of a room; the height, taking in the cornice and mouldings, being 12 feet 6 inches, and the whole compass 83 feet 8 inches; also the three window-shutters are each 7 feet 8 inches by 3 feet 6 inches, and the door 7 feet by 3 feet 6 inches; the door and shutters, being worked on both sides, are reckoned work and half work? Ans. £36, 12s. 24d.
IV. SLATERS' AND TILERS' WORK.
In these articles, the content of a roof is found by multiplying the length of the ridge by the girt over from eaves to eaves; making allowance in this girt for the double row of slates at the bottom, or for how much one row of slates or tiles is laid over another.
When the roof is of a true pitch, that is, forming a right angle at top, then the breadth of the building with its half added, is the girt over both sides.
In angles formed in a roof, running from the ridge to the eaves, when the angle bends inwards, it is called a valley; but when outwards, it is called a hip. Deductions are made for chimney shafts or window holes.
Ex. 1.-Required the content of a slated roof, the length being 45 feet 9 inches, and the whole girt 34 feet 3 inches? Ans. 174-104 yards.
Ex. 11.-To how much amounts the tiling of a house, at 25s. 6d. per square; the length being 43 feet 10 inches, and the breadth on the flat 27 feet 5 inches, also the eaves projecting 16 inches on each side, and the roof of a true pitch? Ans. £24, 9s. 5fd.
PLASTERERS' work is of two kinds, namely, ceiling—which is plastering upon laths and rendering, which is plastering upon walls; which are measured separately
The contents are estimated either by the foot or yard, or square of 100 feet. Enriched mouldings, &c., are rated by running or lineal measure.
Deductions are to be made for chimneys, doors, windows, &c. But the windows are seldom deducted, as the plastered returns at the top and sides are allowed to compensate for the window opening.
Ex. 1.-How many yards contains the ceiling, which is 43 feet 3 inches long, and 25 feet 6 inches broad? Ans. 122.541. Ex. 11. To how much amounts the ceiling of a room, at 10d. per yard; the length being 21 feet 8 inches, and the breadth 14 feet 10 inches ?
£1, 9s. 8ąd. Ex. 111.-The length of a room is 18 feet 6 inches, the breadth 12 feet 3 inches, and height 10 feet 6 inches; to how much amounts the ceiling and rendering,—the former at 8d. and the latter at 3d. per yard,—allowing for the door of 7 feet by 3 feet 8 inches, and a fire-place of 5 feet square?
Ans. £1. 13s. 34d.