ROAD-DRAGS. WATER FIGURES 



489 



a brace two inches thick and four inches wide should be placed diagon- 

 ally to thorn at the ditch end. The brace should be dropped on the 

 front slab, so that its lower edge shall lie within an inch of the ground, 

 while the other end should rest in the angle Vjetween the slab and the 

 end stake. 



A strip of iron about 3^ feet long, 3 or 4 inches wide, and \ of 

 an inch thick nriay be used for the blade. This should be attached to 

 the front slab, so that it will be \ inch below the lower edge of the 

 slab at the ditcli end, while the end of the iron toward the middle of 

 the road should be flush with the edge of the slab. The bolts holding 

 the blade in place should have flat heads, and the holes to receive them 

 iihould be countersunk. 



If the face of the log stands plumb, it is well to wedge out the lower 

 edge of the blade with a three-cornered strip of wood to give it a set 

 like the bit of a plane. 



A platform of inch boards held together by three cleats should be 

 plac(;d on the stakes betwe(.'n the slabs. These boards should be 

 spaced at least an inch aparf. to allow any earth that may heap up and 

 fall over the front slab to sift through upon the road again. 



Data on Water 



1 U.S. j?allon 

 1 U.S. gallon 



1 cu. ft. wator 

 1 cu. ft. water 



2.31 cu, in. 

 8i lb. 



62.5 lb. 

 7.48 j?al. 



Feet-head of water, and equivalent pressure 



