DRAINAGE 95 



9. What relation does the line of targets or sights in the target 

 method of digging ditches to grade, bear to the grade line? 



10. What points should be observed in selecting drain tile? 



11. Explain in detail how the targets are located. The line. 



12. Describe the use of the tile hook. 



13. How should tile be fitted? 



14. How may tile be laid through quicksand? 



15. What is meant by "blinding" the tile? 



16. WTiy should tile lines be inspected? 



17. Describe the work of inspection of tile drains. 



