EARTH, SAND-CLAY, AND GRAVEL ROADS. 
27 
haul. In general, where the material consists of earth it is loosened 
with plows and the economical method of hauling is fixed by the 
haul length about as follows: 
For lengths of haul not exceeding 150 feet, drag scrapers; for 
lengths of haul between 150 feet and 600 feet, wheeled scrapers; 
for lengths of haul above 600 feet, wagons. Where the material con- 
sists of solid rock it must be loosened by drilling and blasting and 
practically always is hauled in wagons or carts, regardless of the 
haul length. 
The two types of plows commonly used in road grading are shown 
in Plate III, figures 1 and 2. The former is the type generally used 
for loosening ordinary soils, while the latter is used for breaking up 
hardpan, old road 
surfaces and other 
earth unusually diffi- 
cult to loosen. Either 
type is draAvn by 
four horses, or in 
some cases by a trac- 
tion engine, and is 
operated by three 
men, including the 
driver. Plows of the 
type shown in figure 
1 of Plate III aver- 
age about 150 pounds 
in weight and sell at 
an average price of 
from $12 to $18, but 
heavier plows of this type range in cost up to about $30. With aver- 
age soil conditions they may be made to turn a furrow about 7 or 8 
inches deep and from 8 to 10 inches wide. The hardpan plows of the 
type illustrated in figure 2 of Plate III vary considerably in weight 
and selling price but cost more than the turn plows. One reason for 
the higher cost is that the points must be made of a very high grade 
of sjteel in order to be durable. 
A drag scraper of the common type is illustrated in figure 16. 
Such scrapers are made in 1-horse, lj-horse, and 2-horse sizes, which 
have respective rated capacities of 3, 5, and 7 cubic feet. Drag 
scrapers have an average weight, when empty, of from 75 to 100 
pounds, and an actual capacity of about three- fourths the rated 
capacity. The price, f. o. b. factory, averages about from $4 to $6 
per scraper. 
In operating drag scrapers the drivers also may load and empty 
the scraper, but frequently it is economical to provide additional 
Pig. 16. — Drag scrapers at work. 
