LEVELLING AND TOPOGRAPHY. 



69 



figures need not be retained after the contours are 

 sketched in and numbered. 



13 5 13 2 13 12 7 12 6 18,5 ^lUi 12 2 12.0 11.9 12.0 



Fig. 13. — Topography by Contours. Squares loo feet, Level Datum 

 10 feet. Interval between Contour Lines -^ foot. 



This method of representing topography is so com- 

 plete that a plan for drainage may be accurately laid 



