PREPARATION OF THE DESIGN 89 

 AB+IJ ._ 575 + 4-25 _ 



2 2 



CD +EF+GH+5 = 575 +6+5 +5 = 

 2175; 2175-1- (5 -i)=5'4375, which is the mean 



^> 



6>-B 



- 



o 



o 



r 



DIAGRAM 26. 



level for the whole. The truth of this can be 

 checked by working the sections the other way, 

 i.e. A I and so on. A " hanging " level, i.e. one 

 which runs on a uniform slope, can be made 

 from this by raising and lowering the corners, still 

 keeping the average 5*4375. 



