Wind Mills
Windmills have not always been the landmark of
Holland.
In fact they were not even invented in Holland.
The first mills were floating mills, which is convenient
in this land of highly variable wind conditions.
They could easily be turned when the wind direction changed.
Wind power contributed greatly to the might and whealth of Holland in the 17th
century; wind power was used to saw wood, for grinding wheat, linseed etc.
The Dutch could build ships faster than anyone else in this period
which resulted in a great naval power challenging even the British.
A century later the British catched up, started the industrial revolution
and became the world power
that they remained until the 20th century.
The first industrial area in Holland was located along the banks of
the river Zaan, a few km North of Amsterdam.
Windmills lined up along this river where sea ships would unload their cargoes from
all over the world.
The Russian emperor Peter the Great visited this area to learn the art of shipbuilding.
The little house in which he lived for a short time, can still be seen in Zaandam.
And although the vast majority of the windmills have disappeared,
there are still several hundreds remaining.
Most of the remaining windmills have been used to
pump water. The one shown here stands along the river Rotte.
It used to carry water from the lower-lying lake (Bergse Voorplas,
to be seen on the right behind the trees) to the Rotte.
The mill's sails drive a water-wheel through a system of (wooden)
cog wheels.
Windmills powering water pumps were invented in the 15th century.
The windmill has a shaft connecting the sails with a water pump.
The traditional pump is a water wheel.
In most countries the wheel in a water mill is used
to convert the power of flowing water into mechanical power.
Here the power of the wind is used to force the water flow from
lower to higher level.
This system does not depend on the presence of tidal motion,
so it can be used in more locations.
The difference in water level against which the
windmill can pump the water is limited to at most 1.5 m,
so for deep polders a single windmill was insufficient.
This problem was solved by putting a number of mills (usually 3 or 4) in series.
This way a water level difference 3 or 4 times larger can be handled.
The system can still be seen in a number of places in Holland.
The photo shows three of the four mills at Zevenhuizen. Each mill pumps the water up
over 1.20 m. Between two mills there is a canal, as can only just be seen in the photo.
Later on screw pumps were widely used with electrical pumping stations
(see the section on the drainage system in Holland).
These pumps can handle much larger level differences.
Traditionally a considerable number of mills were built on the city walls,
like here in Gorinchem. This location was favoured because it was higher
so that the mills could catch more wind.
The mills in the city were not used for pumping water. They were corn-mills
that worked for bakeries or for the brandy industry. There are only a few left that
can be seen in their original setting.
The largest corn-mills are found in Schiedam where they delivered to the brandy
industry which was very important in that city.
These mills were also built on the city walls but since the walls are torn down
they are now standing along an ordinary canal.