. Agriculture; a text for the school and the farm . -ers are coming to demand improved roads for teaming andautomobiles. 2. Types of Roads Roads are generally considered under the followingtypes: (1) earth roads, (2) sand clay roads, (3) gravelroads, (4) macadam roads, (5) bituminous macadam roads,(6) brick roads, and (7) concrete roads. The discussionin this chapter will be confined to the earth roads, sincethese are the most necessary and practical study for thepublic schools. Earth roads.—A chain is no stronger than its weak-est link; so, also, a road is no better than its poorest
. Agriculture; a text for the school and the farm . -ers are coming to demand improved roads for teaming andautomobiles. 2. Types of Roads Roads are generally considered under the followingtypes: (1) earth roads, (2) sand clay roads, (3) gravelroads, (4) macadam roads, (5) bituminous macadam roads,(6) brick roads, and (7) concrete roads. The discussionin this chapter will be confined to the earth roads, sincethese are the most necessary and practical study for thepublic schools. Earth roads.—A chain is no stronger than its weak-est link; so, also, a road is no better than its poorest means that the heaviest load that can be drawn overa public highway is the load that can be drawn up thesteepest hill, through the worst ruts or mud-holes, or overthe deepest stretch of sand. Hence the importance of low-ering or going around the hill, and eliminating the mud-holes, ruts and stretches of sand. 3. The Location of a Road Public roads should, as far as possible, be located instraight lines. In hilly or mountainous regions, however,. Cross Sec+ion French Roacf(Roman Meihod),previous to mimimmmikij Cross Section of7resao0Kj&f Road^ mS. • Cro&s. SectiQn Telford Road 1820 Cross Section Macadam Road, IBIG, CroiS Section of Modern Macadam fi4cissachusefts) Rbcdwith l^sf>oped foundatior}. Cross Section of Modern Mocodom Rood. Cross-sections of different types of roads. 424 AGRICULTURE this rule must often give way to avoid the climbing of tooheavy grades. Straightness and grade.—To lift a ton one foot highrequires two thousand foot-tons of energy. On a road sur-face requiring one hundred pounds traction per ton, thesame energy would roll the ton a horizontal distance oftwenty feet. As far as the actual amount of energy used isconcerned, therefore, to save one foot of grade, or up-hill
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectagriculture, bookyear
