68 ELEMENTARY AGRICULTURE 



for the open ditch? For the 4 in. tile system? For 

 the 6 in. tile system? 



12. Suppose the open ditch costs 5 cents per rod 

 annually for repairs. In how many years will the open 

 ditch cost as much as the tile drain ? 



13. 'If the above is a true example of the cost and 

 value of drainage, does it pay ? 



14. What would it cost to dig an open ditch on 

 each side of a slough 10 rods wide and 100 rods long 

 at $0.25 per rod? 



15. Is there a place on your farm that needs drain- 

 ing? Measure it. Draw a plan for ditches and esti- 

 mate the cost of both systems. 



