Art. 6.- To measure a Cube. Definition.--A cube is a solid of six equal sides, each of which is an exact square. Rule.—Multiply the side by itself, and that product by the saine side, and this last product will be the solid content of the cube. EXAMPLES. 1. The side of a cubic block being 18 inches, or 1 foot and 6 inches, how many solid inches doth it contain ? ft. in ft. 1 6=1,5 and 1,5X1,5X1,5–3,375 solid feet. Ans. Or, 18 x 18 x 18-=5832 solid inches, and 1923–3,375. 2. Suppose a cellar to be dug that shall contain 12 feet every way, in length, breadth and depth ; how many solid feet of earth must be taken out to complete the same ? 12 x 12 x 12=1728 sold feet, the Ans. Art. 7.–To find the content of any regular solid of three dimensions, length, breadth and thickness, as a piece of timber squared, whose length is more than the breadth. and depth. Rule.-Multiply the breadth by the depth, or thickness, and that product by the length, which gives the solid content. EXAMPLES. 1. A square piece of timber, being one foot 6 inches, or 18 inches broad, 9 inches thick, and 9 feet or 108 inches. long; how many solid feet doth it contain ? 1 ft. 6 in.=1,5 foot 9 inches ,75 foot. Prod. 1,125 X 9=10,125 solid fect, the Ans. in. in. in solid in. Or 18 x 9 x 108=17496 - 1728=10,125 feet. But, in measuring timber, you may multiply the bread: 1 in inches, and the depth in inches, and thut product by the length in fect, and divide the ast product by 144, which will give the solid content in [cet, &c. 2. A piece of timber being 16 inches broad, 11 inches thick, and 20 feet long, to find the content ? Breadth 16 inches. Prod. 176 x 20=3520 then, 3520-144-24,4 feet. Ans. 3. A piece of timber 15 inches broad, 8 inches thick, and 25 feet long; how many solid feet doth it contain ? Ans. 20,8+feet. Art. 8.—When the breadth and thickness of a piece of timber are given in inches, to find how much in length will make a solid foot. Rule.-Divide 1728 by the product of the breadth and depth, and the quotient will be the length making a solid foot. EXAMPLES, 1. If a piece of timber be 11 inches broad and 8 inches deep, how many inches in length will make a solid foot ? 11x8=88)1728(19,6 inches. Ans. 2. If a piece of timber be 18 inches broad and 14 incher deep, how many inches in length will make a solid foor? 18 x 14=252 divisor, then, 252)1728(6,8 inches. Ans. ART. 9.–To measure a Cylinder. Definition.—A Cylinder is a round body whose bases are circles, like a round column or stick of timber, of equal big. ness from end to end. Role.-Multiply the square of the diameter of the end by ,7854 which gives the area of the base ; then multiply the area of the base by the length, and the product will be the solid content, EXAMPLE. What is the solid content of a round stick of timber of equal bigness from end to end, whose diameter is 18 inches, and length 20 fect? 18 in.=1,5 ft. X1,5 Square 2,25 x,7854-1,76715 area of the base. +20 length. Ans. 35,34300 solid content. Or, 18 inches. 18 inches. 324x,7854=254,4696 inches, area of the base. 20 length in feet. 144)5089,3920(35,313 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 ? 11x11x2x20=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. EXAMPLE. How many feet of square edged boards, l. inch thick, including the saw calf, can be sawn from a log 20 feet long and 24 inches diameter ? 12 x 12 x 2 x 20-144240 feet, solid content. As 1 : 40 : : 12 : 334 feet, the Ans. Art. 12. The length, breadth and depth of any square brit 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 swer. 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 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 bricka 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 1728-80.21,6 bricks in a solid foot. 44+40+44+40=168 feet, whole length of wall. -4 times the thickness. 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 lastproduct 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. 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: h2 tonnage ? 84 x 28 x 14:95=350,29 tons. Ans. ! Rt. 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; 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 6X6 X6 : 24 cut. : : 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 21, ewt. ? cut. cut. in. As 18 : 12x12x 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. |