86 OVERHAUL. 



be made on the same sheet of paper; but for the vertical part 

 instead of elevations being referred to a datum plane, at or be- 

 low the lower edge of the profile paper, we have an initial line 

 or axis of abscissas, located somewhere on the profile, from 

 which the ordinates are measured above for plus and below 

 for minus. Connecting the ends of these ordinates, we have a 

 broken line, which in mathematical language may be called a 

 curve, resembling somewhat an ordinary profile, but wholly 

 different therefrom, composed of the elements between the suc- 

 cessive stations. 



If the increment, by the use of which any ordinate is formed 

 from the previous one, is positive, this element of the curve 



BOP 



215 



220 



230 



225 



Stations. 

 Profile of QuarrfitMes. 



235 



FIG. 3. 



will incline upward, will indicate excavation and be shown by 

 a dotted or blue line. If the increment is negative the element 

 of the curve will incline downward, will indicate embankment 

 and be shown in red or by a solid line. So that excavation on 

 the profile of quantities is always shown by an ascending 

 dotted or blue line, and embankment by a descending solid or 

 red line. 



We now consider the balancing line. Some points of this 

 line are always fixed by the patent conditions of the work, and 

 occasionally all points are so fixed, but very often some points 

 on it are indeterminate at first, so that each section is very 



