26 



FARM AND SCHOOL PROBLEMS. 



The following table gives the approximate number of feet 

 of tile which will be required per acre, when laid in parallel lines : 



20 feet apart 2,205 feet 



30 feet apart :.... 1,470 feet 



40 feet apart 1,102 feet 



50 feet apart 880 feet 



100 feet apart 440 feet 



This does not include the intercepting drain which may be 

 necessary in some cases to complete the system. 



The following cuts will illustrate the different systems of 

 laying tile : 



FIG. 3. One system of laying tile] FIG. 4. A common system of 

 laying tile. 



FIG. 5. In which the laterals are laid at right angles to the main. 



