. A manual of the principles and practice of road-making : comprising the location, consruction, and improvement of roads (common, macadam, paved, plank, etc.) and railroads . with area 0, at the preceding intermediate station, and at this sta- 10. „ . 10 X 2 tion Its area, r ig. 153, is —-— At station 0, the cross-section resembles that at station 3, in-Fig. X verted, and is calculated in the same manner by division intotriangles, as is shown in Fig. 154. 10 X 3 Left-hand triangleRijrht-hand triangle - = 210 X 6 = 30. rp ■ • . • 1 4X (6+10+10 + 12) 1 wo remaming triangles = =
. A manual of the principles and practice of road-making : comprising the location, consruction, and improvement of roads (common, macadam, paved, plank, etc.) and railroads . with area 0, at the preceding intermediate station, and at this sta- 10. „ . 10 X 2 tion Its area, r ig. 153, is —-— At station 0, the cross-section resembles that at station 3, in-Fig. X verted, and is calculated in the same manner by division intotriangles, as is shown in Fig. 154. 10 X 3 Left-hand triangleRijrht-hand triangle - = 210 X 6 = 30. rp ■ • . • 1 4X (6+10+10 + 12) 1 wo remaming triangles = = 7d. Entire area, . . - = 121. At station 7, the embankment runs out, and the area = 0. MEAN HEIGHTS. To apply the prismoidal formula to cases of irregular cross-sec-tions, it is necessary to calculate the mean heights of these cross-sections, to be subsequently averaged together to find the middleheight; which produces the middle area. The following problem istherefore to be solved : Given the area of any irregular section, re-quired the mean height which would produce the same area, thebase and slopes remaining the same. 368 APPENDIX. Fig.
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectrailroa, bookyear1853
