4 U 



MECHANICAL. 



over 6 feet diameter, one-half the open- 

 ing to be deducted. 



For openings without frames, measure 

 to the springing for the height by the 

 width, deducting one jamb. 



For arches of vaults, sewers, etc., take 

 the outside circumference by the length 

 and thickness. 



Ovens, coppers, boilers, etc., are meas- 

 ^ured as solid work, deducting only the 

 ash-holes; but all the fire-brick, tiles, etc., 

 although measured alone, are not deduct- 

 ed out of the brick- work. 



Paving is measured by the superficial 

 yard, or 9 square feet, which will require 

 41 bricks when laid flat, and about twice 

 that amount when laid on edge. 



A 9 inch wall will require 14 bricks. 



A 13 inch wall will require 21 bricks. 



A cubic foot of brick-work weighs from 

 120 to 125 pounds, avoirdupois. 



One bushel hydraulic cement will, 

 where mixed with two bushels sharp 

 .sand, serve to lay 150 bricks. 



Mortar when made up should not be 

 •disturbed for several days, and during 

 the period of its consumption should be 

 broken down and "tempered" in no 

 larger quantities than may be required for 

 use from day to day. 



Pointing to fronts is measured by the 

 foot superficial. 



Stone sewer-pipes are measured and 

 valued by the foot run, according to size 

 of bore, from 3 to 18 inches diameter, 

 .and are made in 2 feet lengths. 



Note. — All openings and irregulars, 

 add 50 per cent, apiece more. 



MEASURING TIMBER.— All rectan- 

 gular and square lumber and timber, as 

 plank, joists, beams, etc, are measured by 

 what is called board measure. The 

 board being considered 1 inch thick, and 

 estimated by the square or superficial foot 

 of 144 inches, or the cubic foot of 1728. 

 The calculations are performed by duo- 

 decimals — that is, the foot or inch, etc., 

 divided into 12 parts, thus: 



12 fourths make 1 third. 



12 thirds make...... ...... 1 second. 



12 seconds make..... 1 inch. 



12 inches make 1 foot. 



And the several values arising are : 

 Feet multiplied by feet give feet. 

 Feet multiplied by inches give inches. 

 Feet multiplied by seconds give seconds. 

 Inches multiplied by inches give seconds. 

 Inches multiplied by seconds give thirds, etc. 



This rule is commonly called cross mul- 

 tiplication, on account of commencing 

 with the left hand figure of the multiplier. 

 Example i. — Required the superficial 

 contents of a board of 12 feet 6 inches 

 long and 1 foot 3^ inches broad. 

 f. 1. 

 12.6 

 Multipled by 1.3.6 



12.6 



6-3 



Feet, 1 6. 1.9 



When the two ends of a board are of 

 different breadths, add the two breadths 

 together, and multiply the length by half 

 the same. 



Example 2. — A board that is 1 foot 3 

 inches broad at one end, n^ inches 

 broad at the other, and 18 feet 9 inches 

 long, what is the superficial contents ? 

 15 X 11^ = 26^ =13^ inches. 



2. 



F. I. 



Then 18.9 

 Multipled by 13^ = 1.1.3 



18.9 

 1.6.9 



4.8.3 



Feet, 20.8.5.3 



To find the contents 01 joists, beams, 

 etc. : 



Rule. — Multiply the depth, taken in 

 inches, by the thickness, and this product 

 by the length in feet, and the quotient is 

 the contents in feet. 



Example. — Required the cubic con- 

 tents of a joist 10 inches wide and 12 

 feet 6 inches long ? 



F. I. 

 12.6 



Multiplied by 1.8 



12.6 



8.4.0 



Feet, 20.10.0 

 To find the contents ot solid timber : 

 The solid contents of timber (accord 

 ing to custom) is found by multiplying 

 the length by the square of the }( girth. 



