66 



CBAinSBEET CULTUBB. 



meadow that may be depended upon, is one constructed 

 of clean sand, free from roots, or pieces of turf, and 

 built upon the solid sand or loam, as the case may be. 



If it be desired to build a dam across a meadow con- 

 taining muck six feet in depth, dig a road entirely through 

 the muck, and lay the dam upon a sure foundation, or it 

 will not stand the test. 



Before commencing the dam, learn where you want it, 

 and then how large the flood will require it to be. Its 

 locality must depend upon circumstances ; its dimensions 

 upon the height of water required to flood the meadow. 

 To determine this last point, level the ground with a 

 theodolite, if one is at hand ; if not, take an ordinary 

 A 1 ^_ B 



Fig. 86. — LEVELLINO. 



spirit-level and two boards, and proceed to the lowest 

 spot along the line of the proposed dam ; there drive the 

 boards perpendicularly into the earth, eighteen inches 

 apart, and rest the spirit-level on top of them, pointing to 

 the highest knoll you intend covering with water. Bring 

 it to a level by tapping on top of the highest board. 



Then send your assistant to the knoll, with instructions 

 to erect a pole, and move a white target up or down it, 

 as you direct him, by the motion of your hand. 



By sighting along the top of the spirit-level you will 

 be enabled to judge when the target is level with your 

 eye. 



Having established this point on the pole — ^by a pencil 

 mark — the difference in the height of the two positions 

 may be ascertained by subtracting the height of the mark 



