Εικόνες σελίδας
PDF
Ηλεκτρ. έκδοση

Art. 12. The length, breadth and depth of any square box being given, to find how many bushels it will contain.

RULE. Multiply the length by the breacith, and that product by the depth, divide the last product by 2150,425 the solid inches in a statute bushel, and the quotient will be the answer.

EXAMPLE.

There is a square box, the length of its bottom is 50 inches, breadth of ditto 40 inches, and its depth is 60.inches; how many bushels of coma will it hold?

50X40X60-2150,425=55,84+ or 55 buskels, three decles. Hus. ART. 13. The dimensions of the walls of a brick build

ing being given, to find how many bricks are neces

sary to build it.

RULE, From the whole circumference of the wall measured round on the outside, subtract four times its thickness, then multiply the remainder by the lieight, and that product by the thickness of the wall, gives the solid content of the whole wall; which multiplied by the number of bricks contained in a solid foot, gives the answer.

EXAMPLE. How

many bricks 8 inches long, 4 inches wide, and 24 inches thick, will it take to build a house 44 feet long, 40 feet wide, and 20 feet high, and the walls to be one foot thick ? 8x4x2,5=80 solid inches in a brick, then 1728-80 21,6 bricks in a solid foot. 44+40+.44+40=168 feet, whole length of wall.

4 four times the thickness."

164 remains. Multiply by 20 height.

3280 solid feet in the whole wall. Multiply by 21,6 bricks in a solid foot.

Product, 70848 bricks. Ans.

1

RULE. Multiply the length of the keel by the breadth of the beam, and that product by the depth of the hold, and divide the last product ty 95, and that quotient by the tonnage.

EXAMPLE.

EXAMPI E.

Suppose a ship 72 feet by the keel, and 24 feet by the beam, and 12 feet deep : what is the tonnage ?

72x24x12;-95=218,2+tons. Ans.

RULE II. Multiply the length of the kee! by the breadth of the beam, and that product by half the breadth of the beam, and divide by 95.

A ship 84 feet by the keel, 28 feet by the beam ; what is the tonnage ?

84x28x11--95=350,29 tons. Ans. Art. 15. From the proof of any cable, to find the

strength of another.

RULE.
The strength of cables, and consequently the weights
of their anchors, are as the cube of their peripheries.
Therefore; As the cube of the periphery of any cable,

Is to the scight of its anchor;
So is the cube of the periphery of any other cable,
To the weight of its anchor.

EXAMPLES.

1. If a cable 6 inches about, require an anchor of 21 cwt. of what weight inust un anchor be for a 12 inch cable ?

As 6x6x6:21cut. : : 12x12x12: 18cut. Ins.

2. If a 12 inch cable require an anchor of 18 cwt. what must the circumterence of a cable be, for an anchor of 2 cw.? cut.

cut.

in. As 18 : 12x12x12 : : 2,25 : 216 4216=6 Ans. Art. 16. Having the dimensions of two similar built

skips of a different capacity, with the burthen of one of them, to find the burthen of the other.

RULE. The burthens of similar built ships are to each other as the cubes of their like dimensions.

EXAMPLE.

If a ship of 300 tons burthen be 75 feet long in the keel I demand the burthen of another ship, whose keel is 100 feet long?

T.cut.qrs.lb. As 75 X75X75 : 300 : : 100X100X100 : 711 2 0 24 +

OR

DUODECIMALS,

CROSS MULTIPLICATION, IS a rule made use of by workinen and artificers in casting up the contents of their work.

RULE. 1. Under the multiplicand write the corresponding denominations of the multiplier.

2. Multiply each term into the multiplicand, beginning at the lowest, by the highest denomination in the multiplier, and write the result of each under its respective term; observing to carry an unit for cvery 12, from each lower denomination to its next superior.

3. In the same manner multiply all the multiplicand by the inches, or second denomination, in the multiplier, and set the result of each term one place removed to the right hand of those in the multiplicand.

4. Do the same with the seconds in the multiplier, set. ting the result of each term two places to the right hand of those in the multipiicard, &c.

EXAMPLES. F. 1. F. I. F. I. F. 1. Multiply 7 7 3

7 5

4 6 97 By

4 7
39

5 8 97

[merged small][merged small][merged small][merged small][ocr errors][merged small]
[blocks in formation]

TEST, KOHES AND SEPONDI.

F. 1. Multiply 9 8 6 By 79

[tiplier. 67 11 6

=prod. by the feet in the mu.. 7 3 4 6 "ditto by the inches.

% 5 1 6=ditto by the seconds.

[ocr errors][merged small][merged small][ocr errors]

Product, 55 % 93 9 48 11 2 8 10

How many square feet in a board 16 feet 9 inches long, and 2 feet 3 inches wide : By Duodecimals.

By Decimals.
F. I.

F. 1.
16 9

16 9=16,75 feet. 2 3

S 2,25

33 6
4 2 3

8375 · 3850 3350

F. I. u. 37,687587 8 9

Ans. 87 88

TO MEASURE LOADS OF WOOD.

RULE. Multiply the length by the breadth, and the product by the depth or height, which will give the content in solid feet; of which Ố4 make half a cord, and 128 a cord.

EXAMPLE.

How

many solid foet arr contained in a load of wood, 7 feet 6 inches long, 4 feet 2 inches wide, and 2 foet s inches high?

7 ft. 6 in.=7,5 and 4 ft. 2 in. 4,167 and 2 ft. 3 in= 2,25; then, 7,5 X4,167 31,2525 X 2,25-70,318125 solid feet, Ans.

But loads of wood are commonly estimated by the foot, allowing the load to be 8 feet long, 4 feet wide, and then 2 feet high will make half a cord, which is called 4 feet of wood; but if the breadth of the load be less than 4 feet, its height must be iacreased so as to make half a cord, which is still called 4 feet of wood.

By measuring the breadth and heighth of the load, the content may be found by the following

RULE. Multiply the breadth by the height, and half the product will be the content in feet and inches.

EXAMPLE.

Required the content of a load of wood which is 3 fe 9 inches wide and 2 feet 6 inches high, By Duodecimals. By Decimals. F. in.

F. 3 9

8,75 2 6

2,5

[blocks in formation]

9 4 6 9,375

K. in Ans. 4 8 3 4,687324 84, or half a cord anus

81 inches over. The forogoing method is concise and easy to those who are well : acquainted with Duodecimals, but the following Table will give the content of any loud of wood, by inspection only, sufficiently esett for common practice ; which will be found vory convonionta

« ΠροηγούμενηΣυνέχεια »