Ancient industry that changed the rural landscape

The fields of the northern uplands were once littered with thousands of mini industrial sites, turning the rocks from the landscape into a material vital to farming, construction and almost every other aspect of everyday life.

Lime kilns were used by earlier generations to turn the limestone from which this landscape is formed into quick-lime, which even just half a century ago was vital to a myriad of industrial processes.

In the Yorkshire Dales National Park there are more than 1,000 sites, but unlike lead mining, this bygone industry has largely passed into history unnoticed.

One man from the Ribble Valley has made his life's work recording this process and the impact which it had on the landscape.

David Johnson trained as a geographer, but sees himself as a landscape historian.

"Everything we walked on, sat on, dressed in, slept under, ate or looked at had lime in it somewhere," says David.

"It was obviously used in mortar, whitewash, lime-wash and render."

Farmers used it to improve land and because of its disinfectant qualities it was also used to treat a range of stock diseases.

Until as recently as 2001 it was used as a part of the cleansing of farm buildings hit by the devastating foot and mouth disease.

David Johnson reveals a method from 1759 for treating livestock. "You mixed burnt lime with garlic and marjoram, and then put that on to a fire and put bracken on top to get it really smokey.

"Then drove the cattle through it. That was their way of curing cattle of foot and mouth disease. I was telling this story at a talk and somebody in the audience put her hand up and said 'ah this was Need Fire – that's what they called it in Westmorland'."

We meet at the Penyghent cafe in Horton-in- Ribblesdale, at the heart of a limestone area. From the train window on the nearby Settle to Carlisle Railway you can see some of the finest limestone pavement in the country, the hills are grey from it, massive chunks have been gouged out by quarrying.

We visit the remains of one of several field lime kilns, close to the Salt Lake Cottages between Selside and Ribblehead. "The purpose of the lime kiln was to turn limestone into quicklime, burnt lime, pure and simple," says David Johnson.

"You're basically roasting it. Limestone is calcium carbonate, so you're burning off the carbon and also removing all the moisture. What you're left with is just the calcium.

"There are a lot of misconceptions, and some people think it comes out as a powder, but it doesn't. It comes out in the same form that it went in, except that it would be a lot lighter. It would have lost about half its weight."

This kiln is one of the best surviving examples of the type used in the 18th and 19th centuries to produce lime for fields. On the land it reduced the acidity of the soil.

"But apart from that, if you have a rather heavy soil, a clay soil and you plough it in, the lime acts as a flocculant, which is a delightful word. It broke down the clods of clay, allowing more rainwater to freely drain through it.

"Lime also allowed more air to get into the soil and more heat. So you had a warmer, drier soil, which allowed more worms and bacteria and more nutrient cycling."

The lime from these kilns brought previously unused land in parts of the uplands into production for grazing sheep and cattle.

"In the 18th and 19th century enclosures, they would very often build a lime kiln, just to reclaim that pasture. They'd wall the area, strip the vegetation, drain it, then lime it. Some of the kilns up there were only in use just to reclaim the land and maybe never again."

On some fields lime would be spread as a top-dressing when needed.

The design of the kiln at Salt Lake Cottages is typical of many. Above that arch is a cylindrical stone-built structure housing the kiln. The fire was within this cylinder. The arch underneath was to protect the processed lime coming out at the bottom of the kiln from the weather.

"You've got to see this divided into three sections. It's the middle section where you're basically burning or firing it.

"As you're firing it there the processed stone will drop down to the bottom and cool down ready to be drawn out. Also as you are burning it in the middle, the heat is rising to dry out fresh stone at the top, so by the time this fresh stone gets down to the middle it will spontaneously combust, because of the carbon in the stone and the heat. It will actually burn."

In the middle of the wall at the back of the arch under the kiln is a small "eye-hole" through which the finished quicklime emerged. Above it would have been a small grate for the kindling.

The layers of unburnt limestone above would have had layers of more fuel between them. The kilns would be kept going for a month or so, and then left idle perhaps for 10 years, until they were needed again.

Keith Emerick, an Inspector of Ancient Monuments with English Heritage, says during the Reformation Henry VIII didn't so much destroy the monasteries as recycle them.

"As the monasteries were being dissolved, the people doing that would build a limekiln in the monastery as they're taking it apart. They would then reduce the limestone to produce the lime there and then. One has been discovered in Ripon, several have been discovered in York."

One was discovered in the Redfearn Glassworks excavation at York in the 1980s.

The glassworks was built on the site of old religious buildings and a limekiln was found in the former cloisters.

The idea is thought to have been brought to this country by the Romans, but it goes back even further. "You'd be going back to the Fertile Crescent, back to ancient Babylon, so you'd be going back about 10,000 years," says David Johnson.

By the early part of the 19th century there were thousands of these kilns across the North of England. There were also a small number of the earlier variation, the clamp kiln, based on a pit and similar to those used to burn charcoal. David Johnson has recorded more than 1,100 in the Yorkshire Dales National Park.

"In their complete state about 10 per cent have survived," he says. "There's probably less than 50 per cent where you can go and still see something."

The rest are known about because they were on the first six-inch Ordnance Survey maps from the 1850s.

Only a very small number are protected, either as scheduled monuments or listed buildings. David Johnson hopes that the new Higher Level Stewardship scheme will lead to the kilns which remain surviving longer thanks to payments which encourage farmers to take care of more than just the land.

"They can get grant aid to consolidate a kiln which is worth it. The problem is that to some in the past they were just free quarries.

"The majority of farmers like having them on their land. And I've found very few over the years who've not given a damn."

CW 22/5/10