eling the Bottom.--Where to
begin to lay Pipes.--Mode of Procedure.--Covering Pipes.--Securing
Joints.--Filling.--Securing Outlets.--Plans.

CHAPTER XIII.

EFFECTS OF DRAINAGE UPON THE CONDITION OF THE SOIL.

Drainage deepens the Soil, and gives the roots a larger
pasture.--Cobbett's Lucerne 30 feet deep.--Mechi's Parsnips 13 feet
long!--Drainage promotes Pulverization.--Prevents
Surface-Washing.--Lengthens the Season.--Prevents Freezing
out.--Dispenses with Open Ditches.--Saves 25 per cent. of
Labor.--Promotes absorption of Fertilizing Substances from the
Air.--Supplies Air to the Roots.--Drains run before Rain; so do
some Springs.--Drainage warms the Soil.--Corn sprouts at 55 deg.; Rye
on Ice.--Cold from Evaporation.--Heat will not pass downward in
Water.--Count Rumford's Experiments with Hot Water on
Ice.--Aeration of Soil by Drains.

CHAPTER XIV.

DRAINAGE ADAPTS THE SOIL TO GERMINATION AND VEGETATION.

Process of Germination.--Two Classes of Pores in Soils, illustrated
by cuts.--Too much Water excludes Air, reduces Temperature.--How
much Air the Soil Contains.--Drainage Improves the Quality of
Crops.--Drainage prevents Drought.--Drained Soils hold most
Water.--Allow Roots to go Deep.--Various Facts.

CHAPTER XV.

TEMPERATURE AS AFFECTED BY DRAINAGE.

Drainage Warms the Soil in Spring.--Heat cannot go down in Wet
Land.--Drainage causes greater Deposit of Dew in Summer.--Dew warms
Plants in Night, Cools them in the Morning Sun.--Drainage varies
Temperature by Lessening Evaporation.--What is Evaporation.--How it
produces Cold.--Drained Land Freezes Deepest, but Thaws Soonest,
and the Reasons.

CHAPTER XVI.

POWER OF SOILS TO ABSORB AND RETAIN MOISTURE.

Why does not Drainage make the Land too Dry?--Adhesive
Attraction.--The Finest Soils exert most Attraction.--How much
Water different Soils hold by Attraction.--Capillary Attraction,
illustrated.--Power to Imbibe Moisture from the Air.--Weight
Absorbed by 1,000 lbs. in 12 Hours.--Dew, Cause of.--Dew
Point.--Cause of Frost.--Why Covering Plants Protects from
Frost.--Dew Imparts Warmth.--Idea that the Moon Promotes
Putrefaction.--Quantity of Dew.

CHAPTER XVII.

INJURY OF LAND BY DRAINAGE.

Most Land cannot be Over-drained.--Natu