Windmills are an imposing, elegant and historic feature of the Norfolk landscape, having been present for more than 800 years. Throughout the county, many windmills have been restored and are regularly open to visitors. A handful once again produce flour in the traditional way, demonstrating a traditional rural craft which was almost lost forever.

Windmills do not consume any fossil fuels when they are working, nor emit any greenhouse gases. In our ongoing quest to reduce our personal carbon footprint, the windmill is an awe-inspiring example of 'green' technology. Prior to the 19th century, the only sources of power available to our ancestors - other than those provided by the muscles of their animals - were natural ones.

The force of flowing water to drive waterwheels was widely used throughout Britain, but less so in Norfolk which does not have very many fast-flowing streams or rivers. It does, however, have a relatively open and unrestricted landscape. Its proximity to the north sea helps to generate comparatively high and constant wind speeds, making it an ideal location for windmills.

At one time, almost every other parish in the county had its own windmill, and more than 900 windmill sites in Norfolk have been positively identified. Even today, the remains of more than 120 windmills can be found in the county, although only a quarter of these are almost complete and have been restored.

Most windmills in the county were corn mills. They used millstones, arranged in pairs, to convert wheat grain and other cereals into flour for baking. Some of the restored windmills in Norfolk are now back in working order, so visitors can see at first hand how this was done.

Denver Mill, not far from Kings Lynn in the west of the county, is the tallest working windmill in the county and is open all year round. At Great Bircham Mill, which is open during the summer months, the mill is surrounded by open fields and has its own bakery containing the original coal-fired bake ovens. Here, the farming, milling and baking trades were all close at hand. One of the largest mills ever constructed is Old Buckenham Mill in south east Norfolk, where visitors can find five pairs of millstones all situated on one floor.

Wind power could be put to other uses, however. In the Broadland area of Norfolk, many of the windmills standing by the rivers are actually wind-powered water pumps. These "drainage mills" used scoop wheels and other devices to lift water from the low-lying marshland into the rivers, in order that the dried-out land could be used for grazing and crop-growing.

Wind power was also used in small-scale industry. One of the two mills that used to stand at Cawston drove timber-sawing machinery. The large windmill at Berney Arms, to the west of Breydon Water near Great Yarmouth, was built to grind cement clinker - a kind of chalky mud, dredged from the river - for the adjacent cement works. The old brick tower that was built into the remains of the gatehouse of St Benet's Abbey, near Horning on the River Bure, began life in 1740 as a windmill for grinding colza oil seed. There are also several 19th-century references to industrial windmills in Norwich engaged in snuff grinding, oak bark processing and textile spinning.

The earliest type of windmill to be introduced to Norfolk was the post mill, built completely of wood, and so-named because the whole mill was designed to balance and turn around upon a central wooden post. A long lever, protruding from the rear of a post mill, allowed the miller to push the mill around until the sails, which provided the power, to face into the wind. Post mills began to appear in Norfolk in the thirteenth century and the design proved so popular that they continued to be built until the nineteenth century. In fact, two of Norfolk's three surviving post mills are authentic replicas, built by enthusiasts in the 20th century on, or near, the sites of old mills.

Most of the county's surviving windmills are tower mills. The principal element of this type of windmill is the tower, usually built of brick and circular in plan. The sails are attached to the roof, or cap, of a tower mill, which sits on a circular track above the brickwork and has the ability to turn through 360 degrees, enabling the sails to face the wind.

Tower mills need not necessarily be built of brick; stone was sometimes used. A cheaper alternative was a wooden tower, with eight or ten corner posts braced together and clad in painted weatherboarding. Mills of this type were known as smock mills. Although a cheaper alternative to a brick-built tower, these mills were far more vulnerable to damage from the weather, or to accidental destruction by fire. As a consequence, no complete smock mills survive in Norfolk today. In Broadland, the only smock drainage mill to survive stands at Herringfleet on the River Waveney - just over the Suffolk border.

Windmills, by their nature, were invariably built in exposed positions, and so remained at the mercy of the elements. The present windmill at Billingford, near Diss in the south of the county, was built in 1860 to replace an earlier mill on the site, a wooden post mill. Early photographs, taken in October 1859, show the remains of the post mill after it had been blown over in a strong wind. Remarkably, the miller - who was inside the mill at the time - survived this incident without injury, being sheltered from falling debris by the mill's stout main timbers.

The study of windmills is fascinating, not least because no two examples are exactly the same. Visitors to Norfolk can trace visual differences between the windmills in different areas of the county. Some differences are immediately apparent, although others are more subtle.

The most obvious characteristic is the shape of a windmill's cap, which varied from the north of the county to the west and south. The style most commonly associated with Norfolk is the 'boat-shaped cap', which is rather like the upturned hull of a sailing boat in construction and profile.

Another prominent feature is the fantail, a set of small sails set behind the main ones, which acted automatically to turn the cap of the mill (or the mill body, in the case of a post mill) around to face the sails into the wind. Most fantails have six or eight blades, although some mills had fantails with seven or as many as ten blades. The decoration to mills, such as painting fantails with a red stripe or giving the sails a particular shape, could also indicate that a particular mill builder - or millwright - had been involved in its construction.

Visitors to Norfolk will find mill-hunting an enjoyable (and possibly addictive!) pastime, and can be assured of a warm welcome at many of the corn- and drainage windmills which open their doors during the summer months. The Norfolk Windmills Trust (www.norfolkwindmills.co.uk), an organization dedicated to preserving the county's unique heritage of mills, publishes a leaflet of current opening times. For people wishing to find out more about the background to individual mills, a new book is now available from www.bonwick.co.uk.

References:

Apling, H. 1984. Norfolk Corn Windmills. The Norfolk Windmills Trust.
Detailed study of the county's surviving corn mills, with historical photographs.

Gregory, R. 2005. The Industrial Windmill in Britain. Phillimore & Co. Ltd.
An account of the various uses of wind power which have been noted in Britain.

Smith, A. C. 1982. Corn Windmills in Norfolk. Stevenage Museum Publications.
Location information for all visible corn windmill remains within the county.