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Newcomen Atmospheric Engine 1712

In 1712 Thomas Newcomen invented the atmospheric engine, see Wikipedia Newcomen Atmospheric Engine for a description.  It was not very efficient, so its biggest use was at coal mines to pump out water, as pit head coal was cheap. Read more about Thomas Newcomen
It is believed that by the 1720s there were five Newcomen engines in Swannington.

Califat Newcomen Boiler

Some visitors to Hough Mill provide very interesting remenisences of their lives in Swannington during the 1930’s, 1940’s and 1950’s.  A few have mentioned the boiler  in the Califat, although they did not know what it was.  It seems that it was rediscovered by each new generation of children exploring the spinney.

The Home Guard

The Trust has also been told a story that explains the holes in the boiler.  An army explosives expert came to Swannington to train the Home Guard in the use of explosives.  The boiler was selected as a suitable item to be used during the demonstration.  Small charges were applied and this explained the holes with the edges pressed inside.

We were also informed that during WWII the Home Guard used the tunnel under St George’s Hill (built 1833 for the Coleorton Railway) for machine gun practice.  If you know more about these stories please share your information with us.


In 1969 the Califat Newcomen Boiler was rediscovered in the Califat Spinney by the Baker family while on a walk exploring the former coal mining sites of Swannington.

Historian and industrial archaeologist Denis Baker was a member of the newly formed Leicestershire Industrial History Society.  He knew he had found something of interest, but it was so overgrown.

LIHS contacted the land owner, Wyggeston Hospital Trust and obtained their permission to excavate the object.  An early 1970’s account written by LIHS members Denis Baker and Dick Thomson describes their findings: download LIHS article.

New – For a synopsis of the history of the boiler see the Califat Newcomen Boiler slideshow on our Hough Mill YouTube Channel

Newcomen boiler in-situ in Califat Spinney 1972
Four of the LIHS diggers
Newcomen Boiler outside Abbey Pumping Station - before conservation
Newcomen Boiler outside Abbey Pumping Station - after conservation

The Boiler’s Journey

LIHS obtained Wyggeston Hospital Trust’s permission to transfer the boiler to Abbey Pumping Station in 1972.  It remained there for about 20 years.  Conservation treatment comprised infilling the holes with fibreglass and painting the whole of the exterior with a protective compound.

During the 1990’s LMS decided that the boiler should be transferred to Snibston Discovery Park as that was the home of the coal mining collection.

On the 29th February 2012 the boiler was moved from Snibston Discovery Park to the Califat Spinney.  Denis Baker, who had been involved in the 1972 excavation of the boiler and transfer to Abbey Pumping Station was present to greet the return of his old friend.

Newcomen Boiler at Snibston Discovery Park
Newcomen Boiler arriving at Califat Spinney car park
Newcomen Boiler with Denis Baker, a member of the 1972 excavation team

Cuckoo Gap very kindly brought a manitou machine to move the boiler from the Califat car park to its position at the Alabama pumping engine house complex.  Tree planting and growth since the boiler’s removal in 1972, plus the condition of the archaeological site, meant that it was impractical to return the boiler to its excavation site.   It was thus placed in its 2012 position.

Newcomen Boiler on plinth near Alabama engine house

The loan agreement required the Trust to place a roof over the boiler so work commenced.  Work on the boiler roof had to fit around other Land Management tasks, such as cutting the grass on the Trust’s 14 acres of former coal mine and railway sites.  It therefore took nine months to complete the task.  Leicestershire and Rutland Heritage Forum run the county heritage award every two years and in 2014 this project won the award for Best Project Under £750.

Recycled poles were used for the shelter's uprights
It was only safe to work on the roof when it was dry
The completed shelter

Future Of The Califat Boiler

The boiler is an important 250 year old artefact, one of only seven in the world.  The provision of a roof was an important step in protecting the boiler from further deterioration, as it prevents rain water entering through the hole for the steam pipe at the top of the boiler.  However, the size of the roof means that the bottom part of the boiler is unprotected; humidity and temperature are not controlled.

Swannington Heritage Trust has been working with Leicestershire Museum Service and Leicestershire Industrial History Society to secure the future of the boiler.  LMS employed a specialist conservator to provide a report in 2018.   In March 2020 the boiler was moved to a temporary site.

Phase one conservation treatment was applied by the Historic Metalwork Conservation Company, specialist conservators from Shropshire.  They removed the remains of the 1970s bitumen and cleaned the external surfaces, revealing the bronze sheen of the wrought iron.  The boiler was treated with a rust converter and a specialist primer paint.  The numerous holes filled with black fibreglass patches are now clearly visible.

During August and September 2002 Trust volunteers built a new permanent base for the Newcomen boiler at a prominent site in the Califat Spinney.  On the 19th November 2022 the boiler was very carefully moved and lowered onto the new base.  A roof will be erected shortly.

Newcomen boiler lifted off temporary base
Newcomen boiler moved along the track next to the Califat Spinney
Adjusting the straps to ensure that the boiler is held evenly.
Lowering the boiler onto the bricks took a bit of pushing and shoving
The boiler on the new base.