Harnessing the power of ideas

IT READS like a who’s who of great Victorian engineers; from industrialist James Watt to the railway pioneer George Stephenson. All with one thing in common; some of their greatest inventions helped to revolutionise how windmills grind corn.

In York we have one of Britain’s finest surviving examples; the newly restored mill at Holgate, so it is only fitting that an exhibition charting inspirational ideas that changed the industry is being held there as part of York’s Festival Of Ideas.

Jen Hay, one of the mill’s preservation society members, is collating material ahead of the event and she says by using stories about the Industrial Revolution’s finest minds, the exhibition will not only explore how they helped to improve windmills, people can also see their inventions at first hand.

“As soon as I saw the heading The Concept of Development in the Milling Industry, I thought this is the story of Holgate and all the snippets we’ve learned as we’ve gone along,” says Jen.

“It’s about giving a taster, about this man invented; this man pushed; this man saved hundreds of lives. Inventors that have changed the world and whose work features in our mill.”

People like Edmund Lee. You might not have heard of him, but his inspired invention turned a slow laborious process into one of near consummate ease.

Lee developed the fantail and it put milling into another league. Previously windmills rested on a huge upright post. To keep the sails into the wind, millers swung the whole building round the central post by pushing it on a large beam.

It wasn’t very efficient because each time the wind veered, the mill had to be stopped until it faced the right direction.

An automatic method was needed and in 1745, Lee had the bright idea of mounting the sails and wind shaft in a cap at the top of the mill and adding a fantail at the rear. It was like a small windmill, fixed at a right-angle to the main sails.

When the wind changed direction, it blew the sails of the fantail round and the shaft automatically drove the cap into wind.

But it was only half the solution.

“Sails started off as a framework with canvas over the top which you could furl back,” says Jen. “But you had to stop every time you wanted to change them.”

Again, that meant halting production, which also meant lost money. So Lee came up with a chain which pulled a rod connected to the shutters; it opened or closed them as they turned.

“The fantail must have been as much of a leap as men going to the moon,” says Jen. “Having a top that turned because of the fantail and shutters you could open and shut by hand must have been unimaginable at the time. It was inspirational.”

The first English windmills date back to the 12th century, when Crusaders brought the technology back from the Middle East. But always the biggest headache was how many sails to use. The answer seems simple; as many as possible. However, four was considered best because if one broke, the opposite sail could be removed to maintain the windshaft’s balance.

John Smeaton wasn’t convinced, and in 1759 he experimented with a fifth sail. Smeaton knew it would produce more power but more turbulence as well and that would negate how fast the sails could rotate.

But Smeaton, designer of the Eddystone Lighthouse, was one of the country’s first civil engineers and he had the skills to explore the sails optimum angle into wind. He finally discovered it was fifteen degrees, which solved the turbulence problem and allowed five sails to be fitted. By the mid-eighteenth century, mills were not only automatic, they were more powerful and that meant more flour could be made. There was still a major problem though. Millers had long battled to grind corn at a constant speed, the only way to ensure a consistent grade of flour.

But varying wind velocities made that impossible until James Watt came up with the solution; an improved speed governor. Watt added weighted balls on a shaft and as the sail speed increased they rotated faster. Centrifugal force made them fly further outwards but, just as importantly, as the wind dropped so the weights slowed and flew back in.

“Windmills work according to the speed of the wind, which turns the grindstones faster or slower,” says Jen. “As soon as the balls spin out, a collar is pulled up which acts as a pivot to the top stone and keeps a paper width gap between the stones.”

With a constant rpm, consistently fine flour was achieved at last.

Mills only work between wind speeds of 13mph and 31mph and millers required the understanding of a sea-captain to judge it. But they couldn’t precisely assess the speed and many mills were operated in way too windy conditions. Indeed some went so fast that they caught fire.

Smeaton had already designed an early anemometer and Daniel Defoe published A Table Of Degrees after a dreadful tempest in 1703, but it wasn’t until Sir Francis Beaufort invented his wind scale in 1806 that millers could accurately trim their sails.

And that earned him a place in the exhibition.

“We had a young group visit the mill; they were studying wind so I wrote out the Beaufort scale,” says Jen. “I began to think who was this chap, so I did some investigations. He was a naval officer who took a delight in charting. He also sailed with Darwin, worked until he was 72 and was injured in the Napoleonic wars. A quite remarkable man.”

The last major change in milling came in 1807 when Sir William Cubitt patented the standard design for self-regulating sails. All these innovations can be seen at Holgate, which Jen says was a state of the art mill. And being in York there are some unique features which use technology from the city’s railway engineering works.

“George Hudson pushed the railway to come to York and it seems that engineering came into the mill. One of the features is the curb ring at the top; the jointing is not seen anywhere else and it’s thought to be a crossover from railway technology.”

Less technically-minded volunteers have followed in the illustrious footsteps of the country’s finest engineers and they have produced a mini-revolution of their own. Holgate is once again in working order; one of only three mills remaining to sport Smeaton’s five sail technology.

The original sails were fitted with the splendidly named Captain Hooper’s Patent Roller Reefing Sails, which were made of short lengths of canvas on individual rollers.

The shutters were linked by bars which ran the length of each sail and joined in the centre of the assembly, called the spider.

The new ones fitted last year pivot to 90 degrees and professional millwright Tom Davies says the best way to describe the difference is that Hooper’s were like a roller blind, these are more like a Venetian blind.

Tom also figures in the exhibition; without his skills, the mill wouldn’t have come back to life. And for him working on it was a poignant task. His father restored Holgate Mill half a century ago.

“It’s quite something to be stood where he was all those years ago,” says Tom.

“It’s a moving feeling really; one that provokes thoughts beyond belief.”

They may not have been inventors, but the exhibition will also tell the story of George Waud, Holgate Mill’s original owner. and Eliza Gutch the last.

Mrs Gutch had the foresight to offer the mill to York Corporation for £100, on the understanding that it would be preserved.

Sadly, plans for restoration stalled and The Yorkshire Evening Press spoke of the mill being “doomed to dust and scuttling mice”.

It wasn’t until the preservation society came along that those days of dust and scuttling mice finally came to an end.

Now York’s only windmill is back; a testimony not only to the trust’s volunteers but some of the Industrial Revolution’s finest minds.

“Holgate Mill is the perfect location for this exhibition,” says Jen.

“This is a place of learning that is painless and I hope it will bring these incredible people to life; it certainly has for me.”

•The original concept of development in the milling industry will go on display on Saturday and Sunday at Holgate Mill between 11am and 4pm, as part of the York Festival Of Ideas. Tickets are £3 for adults, children under 16 free.

Festival highlights

A host of big-name writers, thinkers, scientists and artists will be in York for the two-week Festival of Ideas, which starts tomorrow. Here are a few early highlights:

• Astronomer Carlos Frenk recreates the beginning of the universe – Ron Cooke Hub, University of York, 6pm tomorrow

• Author and screenwriter Anthony Horowitz in conversation, University of York Central Hall, 2.15pm on Saturday

• Historian and novelist Alison Weir talks about the background to her latest novel A Dangerous Inheritance, about the younger sister of Lady Jane Grey. Sunday, 2.30pm, Berrick Saul Building, University of York

• Celebrate the music of Bolivia, National Centre for Early Music, 6pm, Monday

• Jung Chang, bestselling author of Wild Swans, in conversation. York Theatre Royal, 7.30pm, Thursday June 21

For more information about all festival events, or to book tickets, visit yorkfestivalofideas.com or phone 01904 324466.