The Aeolus Waterwheel – Merthyr’s Great Wonder

When Rev Sir Thomas Cullum (8th Baronet Cullum) visited Merthyr Tydfil in 1811, one of the sights he was most taken with was the mighty Aeolus Waterwheel at the Cyfarthfa Ironworks, and he even called it ‘the wonder of the place’. Some contemporary accounts actually refer to it as ‘the Eighth Wonder of the World‘. I wonder how many people in Merthyr have actually heard of it nowadays?

‘Cyfarthfa Works and Waterwheel’ by William Pamplin. The Aeolus Waterwheel can clearly be seen at the centre of the illustration. Photo courtesy of Cyfarthfa Castle Museum & Art Gallery

When Richard Crawshay became sole owner of the Cyfarthfa Works in 1791, he began making plans to extend the works and come up with innovative ways to increase iron production. In 1792, he made the engineer Watkin George a partner in the firm, and the latter began making significant progress in maximising the potential of the works.

His major contribution was the construction between 1793 and 1797 of a huge overshot waterwheel to provide the air for the four blast furnaces.

According to volume 5 of Rees’s Manufacturing Industry (1819-20):

“…..the water-wheel is 50 feet in diameter and six feet wide: it is chiefly made of cast iron, and has 156 buckets. The axle is a hollow tube, and is strengthened by twenty-four pieces of timber applied around it. On each end of the axis is a cog-wheel of twenty-three feet diameter, which turns a pinion. On the axis of these are two cranks, and fly-wheel twenty-two feet diameter, and twelve tons weight; each of the cranks gives motion to a lever, like that of a large steam-engine, and works the piston of a blowing cylinder or air-pump 52½ inches in diameter, and five feet stroke, which blows air into the furnace, both when the piston goes up and down. The work on the other side being the same, it actuates in the whole four of these double cylinders; the wheel makes about two and a half turns per minute, and each cylinder makes ten strokes.”

At the time, it was the largest waterwheel of its kind in the world and was named Aeolus after a character in Greek Mythology. Aeolus, as mentioned in the Odyssey and the Aeneid,  was the keeper of the winds and king of the island of Aeolia, one of the abrupt rocky Lipara islands close to Sicily. Later classical writers regarded him as a god.

The wheel was operated by water fed from streams across the river and transported by a massive iron and wood double aqueduct mounted on stone piers between 60 and 70 feet high. This was the famous Gwynne Aqueduct. Sir Charles Manby (later Secretary of the Institution of Civil Engineers) visited Merthyr and commented that the aqueduct:

“…..maintained an apparent lightness of the whole that contrasted with the massy [sic] boundary of the river, has not only a singular, but also a very interesting and pleasing appearance.”

Gwynne Aqueduct from a painting by Penry Williams

This is the same aqueduct that was mentioned in the previous post about the Pont-y-cafnau (

The Aeolus Waterwheel continued to power the blast furnaces until the 1820’s when it was replaced by a steam powered engine, and was subsequently demolished.

The Cyfarthfa Mystery

What better for a cold winter’s night than a gruesome tale of murder and it’s ghostly aftermath?

The following story is one of those tales that has been passed down through many generations (I have certainly heard about it from several different sources), and has passed into Merthyr folklore.

As most people know, Cyfarthfa Ironworks was founded in 1765 by Anthony Bacon, a rich London merchant, and in around 1770 he had a home built for himself on the banks of the River Taff, next to the works, and called Cyfarthfa House.

Cyfarthfa House in the 1790’s from a drawing by William Pamplin. Photo courtesy of Cyfarthfa Castle Museum & Art Gallery

Soon after it was built, one of Anthony Bacon’s maid-servants began a love affair with a young man named William Owen, who, on one occasion presented her with a pair of silver shoe-buckles and a black silk neckerchief. The couple visited the Cefn Fair, but Will noticed that his lady-friend was very reticent towards him, and was paying far more attention to another young man – Benjamin Harry, obviously another would be suitor. To make matters worse, Will noticed that his rival was wearing the fancy buckles and the very silk neckerchief he had presented to his beloved!

On the Sunday following the fair, Will decided to confront the maid. Having attended the evening service at Ynysgau Chapel he went to Cyfarthfa House for an explanation of her behaviour. Will declared his love to the girl and proclaimed his faithfulness to her at all times, but accused her of being unfaithful to him. A heated argument ensued, culminating with Will plunging a knife into her chest. The injured girl managed to get into the house, and climbed the stairs to join the other maids. As she ascended the stairs, faint through loss of blood, she rested her bloodstained hand on the wall for support, before dying.

Ever since then, so the story goes, that subsequent generations who occupied the house decorated the hallway many, many times over, but no matter what they used, be it paint or wallpaper, the bloody hand-print would always show through.

Sir Frederick J Pedler, former mayor of Merthyr and historian, says in his book ‘History of the Hamlet of Gellideg’, that he actually visited Cyfarthfa House in 1926, and was shown the spot where the maid rested her bloodied hand on the wall, and sure enough, there was the shape of a hand print on the wall.

Cyfarthfa House was demolished in the 1930’s, and with it went the hand-print for good.

Many thanks to Chris Parry at Cyfarthfa Museum with additional information about Cyfarthfa House.