90 MANUAL OF GARDENING 
method shown at A, he is obliged to break both edges at every 
thrust of the tool; but when he cuts the slice diagonally, first 
throwing his spade to the right and then to the left, as shown 
at B, he cuts only one side and is able to make progress without 
the expenditure of useless effort. These remarks will apply to 
any spading of the land. 
In large areas, horses may be used to facilitate the work of 
ditching. There are ditching plows and machines, which, 
however, need not be discussed here; but three or four furrows 
may be thrown out in either direction with a strong plow, and 
a subsoil plow be run behind to break up the hard-pan, and 
this may reduce the labor of digging as much as one-half. 
When the excavating is completed, the bottom of the ditch is 
evened up by means of a line or level, and the bed for the 
tiles is prepared by the use of a goose-neck scoop, shown in 
Fig. 79. Itis very important that the outlets of drains be kept 
free of weeds and litter. If the outlet is built up with mason 
work, to hold the end of the tile intact, very much will be added 
to the permanency of the drain. 
Trenching and subsoiling. 
Although underdraining is the most important means of 
increasing the depth of the soil, it is not always practicable 
81. Trenching with a spade. 
to lay drains through garden lands. In such cases, recourse 
is had to very deep preparation of the land, either every year 
or every two or three years. 
