Εικόνες σελίδας
PDF
Ηλεκτρ. έκδοση

18 in.=1,5 ft.

X 1,5
Square 2,25 x,7854=1,76715 area of the base.

+20 length.

Ans. 35,34300 solid content,
Or, 18 inches.

18 inches.

324,7854=254,4696 inches, area of the base,

20 length in feet.

144)5089,3920(35,343 solid feet. Ans. ART. 10. To find how many solid feet a round stick of

timber, equally thick from end to end, will contain when hewn square.

RULE. Multiply twice the square of its semi-diameter in inches by the length in feet, then divide the product by 144, and the quotient will be the answer.

EXAMPLE. If the diameter of a round stick of timber be 22 inches and its length 20 feet, how many solid feet will it contain when hewn square ?

11x11 X2 20:144=33,6+ feet, the solidity when hewn square. Art. 11. To find how many feet of square edged boards of a given thickness, can be sawn from a log

of a given diameter.

RULE. Find the solid content of the log, when made square, by the last article--Then say, As the thickness of the board including the saw calf : is to the solid feet :: so is 12 (inches) to the number of feet of boards.

How many feet of square edged boards, 17 inch thick, including the saw calf, can be sawn from a log 20 feet long and 24 inches diameter ?

12x 12 x 2 x 20-144=40 feet, solid content.

As 1 : 40 : ; 12 : 384 feet, the Ans

EXAMPLE,

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 breadth, 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 an

Siyer.

EXAMPLE,

a

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 corn will it hold ?

50 x 40 x 60-2150,425=55,84+ or 55 bushels three pecks. Ans. ART. 13. The dimensions of the walls of a brick building

being given, to find how many bricks are necessary 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 height, 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 2 inches thick, will it take to build a house 44 feet long, 40 feet wide, and 20 feet high, and the walls to be 1 foot thick?

8x4x2,5=80 solid inches in a brick, then 1728-8021,6 bricks in a solid foot. 44+40+44 +40=168 feet, whole length of wall.

-4 times the thickness.

X

Multiply by

164 remains.

20 height.
3280 solid feet in the whole wall:

21,6 bricks in a solid foot.
70848. bricks. Ans.

Multiply by

Product,

Art. 14.-To find the tonnage of a ship. 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 by 95, and the quotient is the tonnage.

EXAMPLE.

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

72X24 x 12-95=218,2 + tons. Ans.

RÜLE II.

Multiply the length of the keel hy the breadth of the beam, and that product by half the breadth of the beam, and divide by 95.

EXAMPLE

A ship 84 feet by the keel, 28 feet by the beam ; what is the tonnage ? 84x 28 14:95–350,29 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 weight of its anchor;
So is the cube of the periphery of any other cablo,
To the weight of its anchor.

EXAMPLES.

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

As 6 x 6X6 : 21 cwt. : : 12 x 12 x 12 : 18 cwt. Ans.

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

cwt.

in. As 18 : 12 x 12 x 12 : : 2,25 : 216 216–6 Ans. Art. 16.—Having the dimensions of two similar built ships

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

RULE. The burthensrof similar built shijos 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.cwt. qrs. lb. As 75x75.X 75:300 :: 100 x 100 x 100:711 2 0 24+

DUODECIMALS,

OR

By

CROSS MULTIPLICATION, IS a rule made use of by workmen and artificers in cast ing up the contents of their work.

MU RULE. 1. Under the mulplicand 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; ob serving to carry an unit for every 12, from each lower denomination to its next superior.

3. In the same manner multiply all the multiplicand by Me the inches, or second denomination, in the multiplier, and

By set the result of each term one place removed to the righ: hand of those in the multiplicand.

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

EXAMPLES.
F. I. F.I. F.I. F. I,
Multiply 73 7 5

4 6 97
By 4 7

3 9

5 8 97

Pr

an

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

11

FEET, INCHES AND SECONDS.

F. I. Multiply 9 8 6 By 7 93

[tiplier. 67 11 6

=prod. by the feet in the mul7 3 4 6"

=ditto by the inches. 2 5 1 6 =ditto by the seconds.

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

Product, 55 2 9 3 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. 1.

F. I.
16 9

16 9=16,75 feet. 2 3

2 3=2,25

33 6
4 2 3

8375
3350
3350

F. I.
Ans. 37,6875–87 83

Ans. 37 8 3

T

« ΠροηγούμενηΣυνέχεια »