ROADS AND BRIDGES 



the top soil, this can be placed on the surface by carrying 

 the subsoil forward and placing it in the bottom of the 

 grade and carrying the surface soil backward and plac- 

 ing it on top of the new grade. In rare cases the dif- 

 ference in the quality of the material for the surface will 

 make it economy to use the slush, wheel or Fresno 

 scraper rather than the reversible machine, that the earth 

 may be assorted and the best placed above, where it is 



Figure 204. Elevating grader starting to plow out two roadside ditches and elevate 

 the earth to the middle of the roadway. 



utilized in making a better surface. In such cases the 

 road can be finished by passing over several times with 

 the reversible machine, thus shaving the grade down to a 

 uniform line. When the road has been used for some time 

 and the uneven packing has resulted in an uneven grade 

 line, this can be remedied by the reversible machine. By 

 setting the blade nearly at right angles to the line of 

 draft, earth is carried from the high places in the road 

 and left in the low places, thus making a smooth and 

 uniform surface. The expert operator, with a good re- 

 versible machine, can remodel or repair the surface of 

 very rough earth roads to a nicety. (See Slush and 

 Fresno Scrapers, Figures 115 and H5a. 



Excavating cuts and building grades. Where the 

 earth is to be moved not more than five rods the slush 



