82 - GARDEN DESIGN 



need a dumpy it "pays to employ a surveyor to do 

 the work rather than hire the instruments. But its 

 working should be understood as it is often brought 

 into requisition while the plan is being carried out, 

 and the garden designer should be able to check 

 and follow its use. 



Diagram 24 is supposed to represent a section of 

 undulating ground where levels are to be taken at 



DIAGRAM 24. 



every 50 ft., unless it seems advisable to take 

 others in addition. The level is shown by a tripod 

 and a dotted line shows the line of vision from it to 

 the various positions of the staff the vertical 

 lines. The first position of the level is marked 

 I. Looking to the staff at A 5-2 is read. Revolve 

 the telescope, carry staff to B and 2-35 is read. A 

 is a backsight and B a foresight. Leave the staff 

 at B and carry the level forward to position 2, 

 which in this case is taken past C and set up be- 

 tween that point and D. Read B, which as the 

 dumpy level is now on lower ground shows only -5. 

 This is a backsight. Take the staff to C and read 

 4-7. As only one reading is to be taken from C 

 it counts as an intermediate, but is entered in the 



