EARTH, SAND-CLAY, AND GRAVEL ROADS. 



29 



inches up to 12 inches and this better distribution of the material 

 in the embankment tends to prevent inequalities from developing 

 in the finished road surface. 



Wheeled scrapers (fig. 17) are used to a greater extent in road 

 grading than either drag scrapers or wagons. The reason for this 

 is that in road work the haul length falls, more frequently than 

 otherwise, within the limits for which wheeled scrapers are economi- 

 cal. Several different sizes of such scrapers are in ordinary use, but 

 the size employed most commonly has an actual load capacity of 

 from 11 to 15 cubic feet, according to how heavily the load is heaped. 

 Scrapers of this size ordinarily sell for from $35 to $50 f . o. b. factory. 



In operating wheeled scrapers the material is loosened by plowing, 

 in the manner already described, and is loaded by the scooping 

 action of the scraper. 

 Two horses usually 

 are sufficient to draw 

 the scraper after it is 

 loaded, but a second 

 team, called a snatch 

 team, is hitched in at 

 the front of the tongue 

 to assist in loading. 

 The snatch team 

 should consist of either 

 two or three horses, 

 according to the char- 

 acter of the material, 

 and one snatch team 

 should serve several 

 scrapers. The loading and dumping of the scrapers are done by 

 laborers provided for that purpose and not by the drivers. 



A small organization for carrying on grading work with wheeled 

 scrapers may be made up about as given below : 



Fig. 17. — Wheeled scraper. 



Force : 



1 foreman. 



6 to 11 drivers. 



1 laborer for plowing. 



2 laborers for loading scrapers. 



2 laborers for dumping and 

 spreading. 



1 laborer to trim slopes, etc. 



1 two-horse team for plow. 



4 to 8 two-horse teams for scrap- 

 ers. 



1 or 2 two-horse snatch teams. 



Total : 1 foreman, 17 laborers, 11 

 teams. 



Tools 







8 



wheeled 



scrapers 





to 15 cu. 



ft). 



1 



road plow. 



2 



picks. 





2 



mattocks. 





2 



axes. 





3 



shovels. 





(capacity 11 



