176 Duodecimals.
(33) If a house measures within the walls 52 feet 8 inches in length, and 30 feet 6 inches in breadth, and the roof De of a true pitch—what will its roofing come to at 10s. 6d. per square? Ans. £U : 12 : 11J.+
Note.—In tiling, roofing, and slating, it is customary to reckon the flat and half of any building, within the walls, to be the measure of the roof of that building, when the said roof is of a true pitch, i, e. when the rafters are f of the breadth of the building; and if the roof be more or less than the true pitch, they measure from ons side to the other with a rod or string.
(34) What will the tiling of a barn cost, at 25s. 6d. pel square, the length being 43 feet 10 inches, and breadth 27 feet 5 inches on the flat, the eave-boards projecting 16 inches on each side? Ans. £24 : 9 : 5i.-f
4. MEASURING BY THE BOD.
Note.—Bricklayers value their work at the rate of a brick and a half thick ; and if" the thickness of the wall be more or less, it must be reduced to that thickness by this.
Rule.—Multiply the area of the wall by the number of half bricks the thickness the wall is of; the product divided by 3, gives the area.
EXAMPLES.
(35) If the area of a wall be 4085 feet, and the thickness 2 bricks and a half—how many rods doth it contain ?
Ans. c2b-\-rods.
(36) If a garden wall be 254 feet round, and 12 feet 7 inches high, and 3 bricks thick—how many rods doth it contain ? " Ans. 23 rods, ISO feet, 7 inches.
(37) How many square rods are there in a wall (32£ feet long, \i feet 8 inches high, and 2£ bricks thick ?
Ans. 5 rods, 166 feet, 6+in.
(38) If the side walls of a house be 28 feet 10 inches in length, and the height of the roof from the ground 55 feet 8 inches, and the gable, or triangular part at the top, to rise 42 course of bricks, reckoning 4 course to 1 foot: (now 20 feet high is 2J bricks thick, 20 feet more at 2 bricks thick, 15 feet 8 inches more at 1 £ bricks thick, and the gable at 1 brick thick)—what will the whole work come to at £5. 16s. per rod? Ans. £48 ; 12 : 7- +
