MAIN DRAINS. 33 



or too few are opened, which leads to waste on the 

 one hand, and inefficacy on the other. Returning to 

 our level area, we find it necessary to determine the 

 outfall by instrument, and we prefer to any other the 

 improved dumpy level for this purpose. The method 

 is to place the level in a suitable position near the 

 centre of the piece to be drained, and having adjusted 

 it, send a man round the boundary with the levelling 

 staff. He will hold this up, as directed, at the points 

 judged to be the lowest, and the forester will take 

 the levels, entering each reading upon his note-book, 

 and striking out with his pencil each entry when 

 cancelled by the next or some future higher reading. 

 For instance, let the reading at a certain spot be 7*85, 

 and let the next be 8*32 ; the 7*85 being no longer 

 required, a lower spot having been found, is struck 

 out, and so on. Having, by taking readings all round 

 the area (if necessary), determined the exact spot for 

 the outlet, it is marked by a twig or a cut in the turf; 

 and the work of determining the direction of the main 

 drain will follow. 



It is, of course, a foregone conclusion that the 

 forester has, before taking these levels, made himself 

 acquainted with the best means of disposal of the 

 water. He has ascertained the presence or absence 

 of streams, brooks, burns, rivulets, and so on ; or of 

 ditches, road-side water courses, or even of main 

 agricultural drains (the discharge of surface drains into 

 closed drains we will allude to hereafter). Into such 

 a means of discharge he will cut his main drain, 

 commencing, of course, at the lowest end, so that the 

 water may flow from the workers. The direction 



C 



