THE DRAINAGE OF A GARDEN 389 



to your dry well or your point of discharge, and your plan is made. 

 If your garden has no slope, make a similar plan leading to the most 

 convenient outlet. 



All this must be, of course, drawn exactly to the proper scale, 

 on which inches or half inches shall represent feet. Now take the 

 map to the garden, and carefully lay it out, using compasses and 

 measuring lines. Then carefully dig your ditches to the right 

 depth. They should be at least two feet deep, since no water should 

 stand higher than that in the soil. But tile drains are likely to be 

 thrown out of line by the thawing and heaving of the frozen ground, 

 so that they should be set below frost, which may be three feet or 

 more. Old gardeners or stone-masons in your town can tell how 

 deep the frost usually strikes into the soil in winter. The bottoms 

 of the ditches should be carefully graded, preserving a regular slope 

 all the way, with no pockets or cups in them. If possible, the lower 

 part of the grade should be quicker than the first. The outlet 

 ought to be above the level of standing water. To do all this is a 

 delicate task ; you must have a mason's level, and if you can work 

 with a surveyor's, so much the better. 



The tile should be carefully set in the ditches, and held in place 

 by little stones. See that the ends fit exactly. For this purpose, 

 the larger the tiles, the better. Three-inch tile is the smallest that 

 it is wise to use in drains of any length, though for short runs you 

 may use smaller. Where the branches of the drains join, use Y's 

 rather than T's (that is, acute- rather than right-angle pieces). 

 Cover each joint with tar-paper, sod (upside down !), or hay ; and 

 stop the end of the drain, if it is not to be covered, with galvanized 

 netting. Then shovel in the earth all along the line, the subsoil 

 first, the loam last. 



If your soil abounds in large, flat stones, and you are clever in 

 constructing a tunnel with them, you can get rid of the stones, and 

 at the same time drain your land, without the cost of tile. 



