460 Farm Mechanics. 



In the rolling it will be important to firm the outer edges 

 of the gravel first in order that the rolling may not force it 

 outward and destroy the slope. Should the gravel be too 

 dry to pack it must be moistened or the work be suspended 

 to take advantage of the rains. 



To make a good road there should be not less than three 

 3-inch layers, and usually four will be better. Of course 

 a road 6 inches thick will be a great improvement, and 

 often where the travel is light and the road-bed thoroughly 

 made, three inches of good gravel, well placed, will make a 

 great improvement in the road, serving as a wearing sur- 

 face. 



Where the gravel must be crushed and screened to secure 

 the proper sizes the revolving screen represented in Fig. 

 216 should be used and should have two sizes of holes 1.5 to 

 2 inch and 3 to 4 inch in diameter. The coarser size of 

 gravel will form the body of the road while the finer will 

 have to be discarded unless it happens to be of the right 

 quality to use as a binding material or in making a bicycle 

 path along one side of the road. 



574. Roads in Swampy Places. It occasionally happens 

 that roads must be built in places which cannot be drained 

 and which are too soft to permit of the construction of a 

 solid earth foundation. A common way to meet this type 

 of conditions is to lay a foundation of logs, poles or even 

 brush, having the desired width of the road and of suffi- 

 cient body to enable an earth or gravel road to be built upon 

 it. When such roads are built in situations where the wood 

 is kept constantly beneath the water it does not decay and 

 a road of considerable permanence and solidity is secured. 



Where logs are used care is taken to arrange them at 

 right angles to the direction of the road, parallel with one 

 another and like sizes side by side. The depressions be- 

 tween the logs are filled with smaller lo^s or poles, whole 

 or split, while these in turn may be covered with twie^s and 

 limbs forming a mat upon which the earth or gravel road 

 is built. Upon this mat of wood is usually first thrown 



