. A manual of the principles and practice of road-making: comprising the location, consruction, and improvement of roads (common, macadam, paved, plank, etc.) and rail-roads . When the route follows the valley of a stream, it mayconform to its sinuosities, if the turns are not too abrupt,and if the cuttings and fillings on a straighter line wouldbe too expensive, but should approximate to the latterplan, if the importance of the road and the funds at com-mand will justify the increased cost. The former pl?.n,however, generally gives the cheapest and most levelroute ; and guided by this princip
. A manual of the principles and practice of road-making: comprising the location, consruction, and improvement of roads (common, macadam, paved, plank, etc.) and rail-roads . When the route follows the valley of a stream, it mayconform to its sinuosities, if the turns are not too abrupt,and if the cuttings and fillings on a straighter line wouldbe too expensive, but should approximate to the latterplan, if the importance of the road and the funds at com-mand will justify the increased cost. The former pl?.n,however, generally gives the cheapest and most levelroute ; and guided by this principle a blind man was for along time the very best layer out of roads in the hilly re-gions of Yorkshire and Derbyshire. He followed thestreams closely, and when they made too sharp bends,he sought in these arcs the straightest chords whichpassed over practicable ground. When a valley is to be crossed, the route should gen-erally deviate from the straight line ACB, (Fig. 28) andcurve towards the head of the valley ADB, which there isusually shallower and narrower. If it deviated in the other 84 THE LOCATION OF direction, as AEB, itwould Fig. 28. increase the depth andwidth to be filled up, as isshown by the correspond-ing profiles. But sometimes the twosides of the valley ap-proach each other at somepoint lower down, so asto render the space be-tween their banks narrow-er though deeper; and ifon measurement this areais found on the whole to be lessened, so as to require lessembankment, the road should cross at that point insteadof higher up. Another case in Fig. 29. which a valley may,with advantage, becrossed down stream,is when in that partof the valley are founddetached or isolatedhills and ridges, as Eand F, which maycause a great savingof embankment, onthe hue AEFB, com-pared with either thestraight route ACB, or the up-stream one ADB, as isshown in the accompanying plan and profile, in which thesame letters refer to corresponding lines. When a road is to join two pla
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectrailroa, bookyear1853
