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ENGINEERING FOR LAND DRAINAGE. 



The P7'ofile, 



A profile represents a vertical section of the line of 

 survey. The level notes are platted on profile paper 

 on which the vertical and horizontal scales are different 

 to render irregularities of surface more distinct through 

 exaggeration. The method of profiling the level notes 

 is shown in Fig. 15. In this diagram, one space, hori- 



po f t^ 



23466789 10 

 Fig, 15. — Profile of Main A. (See Notes.) 



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zontal scale, equals 50 feet, and one small space, ver- 

 tical scale, equals .2 foot of elevation, which are con- 

 venient scales in making profiles for drainage work. A 

 profile represents the surface line correctly and should 

 be employed in fixing upon a grade line when the work 

 to be done is of any considerable magnitude. 



To determine a grade, draw a thread over the profile, 

 adjusting it to certain points of maximum and minimum 

 grade, until a desirable grade line is represented by the 

 thread. Transfer the elevation of points where changes 

 of grade occur to the corresponding points on the 

 notes, and compute the cuts for each station • The 



