DRAINAGE 
land is to get the water into the tile, 
as it does not draw well, so some 
times gravel is put in. This will help 
for several years, but in a volcanic ash 
soil or in heavy soils it will become silty. 
Junctions 
Laterals should enter the main at an 
angle of 45 degrees, and with a slight fall. 
It is then less likely to clog up, and is not 
so likely to back up and become silty. 
Sometimes the drop will only be one- 
tenth of a foot, sometimes more. 
Sinks 
They are useful in ponds where there 
is a layer of hard clay underlaid with 
sand. They are made by simply digging 
a small well (probably three feet in di- 
ameter and 12 feet deep) down through 
the clay to the sand to let the water 
through. Sometimes this is all the drain- 
age that is necessary. 
Surface Vents 
They may be on the order of silt basins 
or catch basins. Surface vents are used 
to catch surface water. Surface vents are 
also used to afford ventilation in close 
soils. 
Outlets 
Outlets are very important. It is neces- 
sary to have a good outlet. Where the 
outlet is submerged and the velocity of 
the outflow is checked, sediment is apt 
to collect and clog the drain The water 
should have a free spillway at the out- 
let. Vitrified tile, wood or masonry 
should be used at the outlet where the 
drain is exposed to frost. 
Obstructions 
The principal obstructions to tile are: 
1, Small animals. 2, Roots. 3, Silt. 
The outlets should be protected with 
screens to keep out small animals. A good 
screen is made by a %4-inch iron rod set 
one inch apart. The roots of such trees 
as willow, elm, larch, tamarack and soft 
maple are troublesome. Also alfalfa and 
grapevine roots. Trees within 15 or 20 
feet of the drain should be girdled or cut 
down. Silt will be less troublesome in 
large tile. Small tile must be laid true to 
grade to prevent trouble. To locate ob- 
structions dig holes in several places over 
905 
the tile. When below the obstruction we 
find the water will fall away into the 
tile, above the obstruction it will stand 
in the hole. 
Digging, Laying to Grade and Covering 
Ditching Tools—Their Uses 
Tile spading for removing the first 
spading 1s 18 inches long, concave, with a 
square cutting end. It is important that 
the ditch be started properly, so that the 
sides are plumb and smooth. The begin- 
mer makes harder work and less progress 
by cutting the spadeful too thick. Cut 
one inch and dovetail at center. A three- 
foot ditch should be started about nine 
inches wide. The common round-pointed 
shovel may be used to remove crumbs 
from the bottom of first spading. Leave 
crumbs till last in dry weather. The 
second spading is removed by use of a 
spade about 16 inches or less in length, 
concave with rounded cutting edge. The 
second spading should go to within one 
inch of the grade line. Crumbers are 
used to remove crumbs from the last 
spading and bring the ditch to grade. 
They are concave, semi-cylindrical, with 
rounded cutting blade at either end. The 
handle may be set at any angle. Can get 
38-inch or 6-inch size. Man with crumber 
should keep near the one who is laying 
the tile. 
Tile Hooks 
Tile hooks are used for smaller sizes 
of tile, and are a great aid to rapid work 
where the tiles are cylindrical and the 
ditch is carefully prepared. A good hook 
should be less than a right angle, and 
may be made by running a 10-inch bolt 
through the pole about two inches from 
the larger end. The pole should be a 
little larger than a rake handle, and the 
end may be used to tap the tile firmly 
into place 
Laying to Grade 
This may be done by use of a line, by 
use of targets, or by use of line and fre- 
quent cross lines. 
Difficulties 
Quicksand—caving in. 
Laying Tile 
In laying tile take advantage of imper- 
fections in tile and make them fit the 
