TABLE G. Table of the weight of cast iron Pipes, 1 foot long, and of differens thicknesses. 1 3.06 5.06 14 3.68 5.98 2 3 2222 00 00 00 4455 7.36 9.97 12.89 16.11 19.63 8.59 11.51 14.73 18:25 22.09| 4.29 6.9 9.82 13.04 16.56 20.4 24.54 4.91 7.83 11.05 14:57 18:41 22.55 27. 5.53 8.75 12.27 16.11 20-25 24.7 29.45 6.14 9.66 13.5 17.64 22.09 26.84 31.85 6.74 10.58 14.72 19:17 23.92 28.93 34.36 7.36 11.5 15.95 20.7 25.71 31.14 36.81 7.98 12.43 17.18 22:19 27.62 33.29 39.28 8.59 13.34 18.35 23.78 29.45 35.44 41.72 9.2 14.21 19.64 25.31 31.3 37.58 44.18 9.76 15.19 20.86 26.85 33.13 39.73 46.63 10.44 16.11 22.1 28.38 34.98 41.88 49.1 11.1 17.08 23.37 29.97 36.87 44.0851.6 11.66 17.94 24.54 31.44 38.65 46.17 54. 12.27 18.87 25.77 32.98 40.5 48.32 56 45 12.80 19.78 26.99 34.51 42:33 50.46 59. 51 13.5 20.71 28.23 36.05 44.18 52.62 61.36 14.11 21.63 29.45 37.58 46.02 54.76 63.81; 14.73 22.55 30.68 39.12 47-86 56.91 66-27 | 15.34 23.47 31.91 40.65 49.7 59.06 68.73 61 15.95 24.39 33.13 42.18 51.54 61.21 72. 61 16.57 25.31 34.36 43.72 53.39 63.36 73.41 63 17.18 26.23 35.59 45.26 55.23 65.28 76.1 4 7 7 8 7 17.79 27.15 36.82 46.79 56.84 67.65 78.53 18.41 28.08 38.05 48.1 58.91 69.79 81. 19.03 29. 39.05 49.86 60.74 71.95 83.45 19.64 29.69 40.5 51.38 62.59 74.09 86. 20.02 30.83 41.71 52.92 64.42 76.23 88.35 20.86 31.74 42.95 54.45 66.26 78.38 90.81 8 21.69 32.9 44.4 56.21 68.33 80.76 93.49 8 22.09 33.59 45.4 57.52 69.95 82.68 95.72 9 22.71 34.52 46.64 59.07 71.8 84.84 98.18' The following TABLE of the weight of different substances used in building and engineering requires no ex planation. pounds. 8788 8915 557 18 8396 524.75 4.852 Names of Bodies. Copper, cast.. Weight of a Weight of a Weight of a Weight of a Number of cubic foot in cubic foot in cubic inch in cubic inch in cubic inches in pounds. a pound. Iron, cast.. 7271 454 43 4.203 .263 3.802 Iron, bar.. 7631 476.93 4.410 •276 3.623 The foregoing tables and rules will be found of the ut most service, in the ready calculation of the weight of materials commonly used in engineering. What is the weight of a bar of Swedish iron 16 feet long. 3 inches broad, and 1.1 inch thick? = By table B, 3.38 is the weight of a piece of Swedish iron, of one foot long and one inch square, wherefore, 3.38 x 16 x 3 162.24; and then for the fraction 1, in table A, we have for the weight of 1 foot by ·1 of an inch square = 034; hence, 034 × 3 × 16 = 16.32; wherefore the sum of the two = 162.24 + 16·32 = 178-56 lbs., the weight. If we wish the weight of an equal bar of cast iron, we must employ the multipliers in table D; hence, 178.56 x 925 = 165.168. If we wished it for lead, the multiplier from the same table being 1.457, we have, 178.56 x 1.457 = 260 1619 lbs., &c., &c. Then if lead were 1 penny per pound, the price of such a bar would be The following practical rules are often useful and may be easily remembered. For round bars of iron, diameter (m) x length in ft. × 2·6 wrought iron in lbs. diameter (m) × length in ft. × 2.48 cast iron bars in lbs. A cylindrical bar is 2 inches diameter and 29 inches long, therefore, 22 × 2·5 × 2·6 = 26 lbs. if it be wrought iron, but if cast, 22 × 2.5 × 2.48 24.8 lbs. = Multiply the sum of the exterior and interior diameters of a cast iron ring by the breadth and thickness of the rim, and also by 0 0074, he results will be the weight in cwts. HYDRODYNAMICS. As hydrostatics embraces the consideration of fluids at rest, so hydrodynamics or hydraulics comprehends the circumstances of fluids in motion. Of this science, little, comparatively speaking, is yet known; but as it is of the utmost importance to man, we will endeavour to lay before our readers a statement of the more important results of recent inquiry into it. If a fluid move through a pipe, canal, or river, of various breadths, always filling it, the velocity of the fluid at different parts will be inversely as the transverse sections of these parts. a с d B Thus let there be a canal, AB, of various breadths at different places, then will the velocity in the portion ab be to that of the velocity in cd, as the area of the cross section at cd is to that at ab, and the velocity at ef will be to that at cd as the area at cd is to the area at ef, being always in inverse proportion. : Suppose the velocity at ab 10 feet per second, and the area there 100 feet, then if the area at cd be 25 feet, we have 25 100 :: 10 40 feet, the velocity of the water at cd; and if the area at ef be 50 feet, then 50: 25:: 40 : 20 feet, the velocity at ef, the canal being kept continually full. The quantity of water that flows through a pipe, or in a canal or river, at any part, is in proportion to the area multiplied by the velocity at that part. The calculation of the motion of rivers is often of the highest utility to the engineer. This is sometimes done by the employment of very intricate formulas, but such methods, if easier could be found. would evidently be in 195 |