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Table I.

Explanation. —At the head of this Table , over each verti-cal column, is the thickness of the wall in bricks and halfbricks, viz, from ^ a brick to 5 bricks ; the first verticalcolumn, or that on the left hand, contains the number ofrods, from £ to 21, and each succeeding column towards theright shows the number of rods, quarters, and feet, reducedto a brick and a half, according to the thickness expressed atthe top of the column, and to the number of rods to befound in the same horizontal line in the first column.

Use. —Suppose a wall, 2£ bricks thick, contained 8 rods,how many standard rods does the wall contain ? Look for 8rods in the first column, carry your eye horizontally to the2J brick column, in which you will find 13 1 22 ; that is,13 rods, 1 quarter, and 22 feet; and so proceed for any otherquantity and thickness.

Construction of the Table .—Multiply the number of super-ficial rods expressed in any number of the first column, bythe number of half bricks that the wall is in thickness,divide the product by 3, and the quotient will exhibit thenumber of reduced rods : multiply the remainder, if any, by272, and -t- of the product will be reduced feet; the inchesnot being noticed. Now, as 68 feet are the quarter of a rod,the quotient, if it equal or exceeds 68, must be dividedthereby, and the last quotient will give the quarters of a rod,and the remainder, if any, will be feet.

Example. —Let it be required to find the quantity of re-duced work in a wall 2ijf bricks thick, the superficial measurebeing 8 rods :

8

5 half bricks Then 68 ) 90 ( 1

- 68

3) 40 —

- 22

13 90

Rds. Ft. R. Qt. Ft.

That is 13 90 = 13 1 22

And thus for any other number of superficial rods. A Table,similar to the above, may be found in Leadbeater ’s Gentle-man’s and Tradesman’s Assistant, second edition ; and alsoin Crosby’s Builder's Price Book.

Table. II.

Explanation and Use. —The first column contains thenumber of superficial feet, from 1 to 10 inclusive, the com-mon difference being 1; from 10 to 100 inclusive, thecommon difference being 10; from 100 to 1000 inclusive,the common difference being 100 ; from 1000 to 10,000 in-clusive, the common difference being 1000 ; and from 10,000to 90,000 inclusive, the common difference being 10,000.The adjacent vertical columns, towards the right, show thenumber of bricks respectively required to build a wall at thethickness of 1, 1£, 2, 2^ bricks, according to the super-ficial feet expressed by the number in the first verticalcolumn, in the same horizontal line.

Let it be required to find the number of bricks necessaryto build a wall half a brick thick, containing an area of 4850feet : Divide the number into its component parts thus,4850 = 4000 + 800 + 50, then look for each of these partsseparately, and you will find, that

4000 will require 22058

800 „ „ 4411

50 „ „ 275

and the whole 4850 „ „ 26744

Again, let it be required to find the number of bricks thatwill build a wall two bricks thick, containing an area of35,864 feet: then say,35,864=30 000+5,000 + 800+60+4,and you will find that—

I add theset together,

30000

5000

800

60

4

35864

will require

661764

110294

17647

1323

88

791116

,, ,, jjjjO

Construction .—Reduce the standard rod of 272 r eet > ^the given area, into walls of half a brick thick ; then say>^ 8the number of feet in the standard, thus reduced, is t0 ^area reduced to the same thickness, so is 4,500 brick 3 ;quantity required to build the former, to the quantityquired to build the latter. . jjj

Enample I.—How many bricks will be required to d ?a wall containing an area of 35,864 feet, two bricks tbicThen 272 35864

3 4

816 : 143456 : : 4500

4500

71728000

573824

816) 645552000(791117 the answer.571274357344

912

816

960

816

1440

816

6240

5712

The answer is within one of what is obtained. ^ r °j 0 gt, i®Tables; the difference arises from the fractions beingadding the several parts together. . , jjoi^

Example II.—How many bricks will be required o>a partition wall, half a brick thick, containing an4850 feet ?

272 4850

3 1

Then 816 : 4850

4500

2425000

19400

816 ) 218250001632

5505

4896

6090

5712

3780

3264

5160

4896

264

: 4500

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