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Art. 14.-To find the tonnage of a ship. Rule.-Multiply the length of the keel by the breadth of the leam, and that product by the depth of the hold, and divide the last roduct 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 ?

72X24X 12-95=218,2 +-tons. Ans.

RULE II.

Multiply the length of the keel by the breadth of the beam, and bat 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 la: tonnage ? 84 x 28 x 14+95=350,29 tons. Ans. BIRT. 15.–From the proof of any cable, to find the strength

of another.

Rule.—The strength of cables, and consequently the weights of heir 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 cable,
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 6x6x6 : 21 cwt, : : 12 x 12 x 12 : 18 cut. Ans.

2. If a 12 inch cable require an anchor of 18 cwt. what nust the circumference of a cable be, for an anchor of 21 ewt. ? cut.

cut.

in. As 18 : 12 x 12 x 12 : : 2,25 : 216 21636 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.

3

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

EXAMPLE.

If a ship of 300 tons burthen bc 75 feet long in the kes I den and the burthen of another ship, whose keel is 1 feet long?

cwt.
qrs.

Ib. As 75 x 75 x 75:300 :: 100 x 100 x 100:711 2 0 21-1

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DUODECIMALS,

OR

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

RULE. 1. Under the nulplicand write the corresponding deno mivations 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 diz. nomination to its next superior.

3. In the same manner multiply all the multiplicand lig the inches, or second denomination, in the multiplier, and 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, «et. ting the result of each term two places to the right hand of those in the multiplicand, &c.

EXAMPLES.

F.I. F.I. F.I.
Multiply 7 3 75

46 97
By 47

3 9

58 97

F. I.

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F. I.

Multiply 9 8 6
Ву 7 9 3

tiplier. 67 11 6 sprod. by the feet in the mul7 3 4 6 "I

ditto by the inches. 2 5 1 6 =ditto by the seconds. 75 5 3 7 6 Ans.

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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. 1.
16 9

9=16,75 feet. 2 3

2 3=2,25

16

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TO MEASURE LOADS OF WO01). RULE.-Multiply the length by the breadth, and the product by the depth or height, which will give the content in solid feet; of wk ch 6 make half a cord, and 128 a cord.

EXAMPLE Ilow many solid feet are contained in a load of wood. 7 feet 6 inches long, 4 feet 2 inches wide, and 2 feet 3 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 x 4,167–31,2525 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, wbich is called 4 feet of wood; but if the breadth of the load be less than 4 feet, its height must be increased so as to make half a cord, wnich is still called 4 feet of wood.

By measuring the breadth and height 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 feet 9
inches wide and 2 feet 6 inches high.
By Duodecimals. By Decimals.

F. in.
3 9

3,75
2 6

2,5

F.

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9,375

re

9 4 6

F.in.
Ans 4 8. 3 4,6875=4 87 or half a cord and er

inches over. The foregoing method is concise and easy to those who aro woli acquainted with Duodea.nals, but the following table will give ho sontent of any load of wood, by inspection only, sufficiently exant for common practico; which will bo found ver ennvenient.

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A TABLE of Breadth, Height, and Conte». 2011, e prodaella Breadth. Fleight in feet.

Inches. et; id ft. in. 1 !2134 1 2 3 4 5 6 7 8 9 10 11

2 6
153045 60

4 5 6 7 9 10 11 12 14 16,31 47162 oad of

1 3 4 5 8 9 10 12 13 14 8 16:32' 18'64 1 3 4 5 7 8 911121315

9 1117133:3,19 661 1 3 4 6 7 8 91111214,15 9131

10 11733 15168 2 3 4 6 7 9 10 11 13!14/16

11 31135

1035 53 70,1 2 3 4 6 7 9 10 12 13|15 16 3 0 1236 54 72 2 3 5 6 8! 911 12 14 15017

1937 56 74 2 33 6 8911 12 14 16 17 19'38 5776

10/11/13 14 16 17 3 !!19: 39 59 78

7 8110111 13 15 16 18 4 20.4060801 2 3 71 8 10 12 13 15 17 18 5 1214162821 2 3 71 8 10 12 14 16 17 19 6 121 1263 841 2 4 5 7 9 11 12 14 16 18 19 7 ||:22 4:3 6486) 2 41 5 7 9 11 13 14 16 18 20 8 122.4-166,88

9 11 13 15 17 18 20 i the proku

9 |23,456890 2 4 6 7 9 11 13 15 17 19 21 10 12:3 16'69'92 1 2 6 7 912113.1511711921 11 12:3 17:70 944 2 4 6 8 10 12 14 16 18 20 22 0 124/48 7296 2 4 6 8 10 12 14 16 18/2022

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TO USE THE FOREGOING TABLE. First measure the breadth and height of your load to the nearest average inch; then find the breadth in the left hand column of the table, ihen move co the right on the same line till you come under the height in feet, and you will have the content in inches, answering the feet, to which add the content of the inches on the rig and divide the sum by 12, and you will have the true content of the load in feet and inches.

Note.-The contents answering the inches being always small, may se added by inspection.

EXAMPLES 1. Admit a load of wood is 3 feet 4 inches wide, and 2 feet 10 inches nlges required the content.

Thus, agumst 3 feet 4 inches, and under 2 feet, stands 40 inches; and un der 10 inches at lop, stands 17 inches: then 40+17557, true content in inches, which divide by 12, gives 4 feet 9 inches, the answer.

2. The leadth being 3 fet, and height 2 feet 8 inches; required the con

ord and es 00. ho are wel

will give de

lent

y estrella

Thus, with breadih 3 feet 0 inches, and under 2 feet ator, stando $6

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