Harnessing the Flow
The Medieval Era / The Late Age Of Enlightenment
Father Edmund closed the doors of the abbey and made the walk through the old, twisted oaks to the millhouse he helped build so long ago, when he was first ordained. It was so long ago, he mused, but even as an old man now, he still appreciated it’s work – and its blessings. A wooden waterwheel creaked steadily as the river current slowly spun it. The good friar opened the wooden door and was met with the groaning of wooden gears as they moved the power of the river to the great millstone, grinding grain for the monastery and the local village. He greeted Father William, as the young acolyte, dressed in rough wool robes adjusted the sluice gates with careful precision. The milling stones must spin just right – not too fast, and not too slow. Outside the mill, peasants wait, with full sacks of barley and grain from the manor lords fields, grateful that the mill spared them from hours of hand-grinding.
Across the English Channel, in what is now Spain, Muslim and Christian farmers wait shoulder to shoulder outside Valencia, gathered at dawn. The irrigation canals – the acequias – are being opened so that water from the Turia River can feed the stone lined channels with the life-giving blessings of water, to their groves of olive, almond and pomegranate. There are no differences here, people of different faiths bound together in professional dependance on the abundance of water in an otherwise dry land.
East and somehat little north of there, Hendrik van der Meer scrambled up the ladder. The poldermill, or watermill, had stopped spinning. For the second time this week, this old mill had stopped in its important task of pumping water from the field and out to the sea. Without it, the fields would fill with briny seawater, and the grasses the cattle relied upon, would whither, and die, the soils poisoned with salt. The community needed this mill running. A timber beam had slipped out of place, threatening to jam one of the gears – again. Uttering a silent curse he was glad his wife wouldn’t hear, he wiped the sawdust and sweat off his brow and wedged the giant bean back into place with an iron spike, and secured it with smaller spikes of iron. “That’s going nowhere…”. Outside, cattle continued grazing the fertile land – once a briny swamp, since reclaimed for this small, but vibrant farming community.
As the middle ages went on, the transition from using water solely for irrigation, to harnessing its kinetic energy for mechanical tasks, marked a pivotal evolution in human technological development. Initially, water served as a vital resource for agriculture, exemplified by the acequias of medieval Valencia, where Muslim and Christian farmers collaboratively channeled the Turia River to irrigate groves of harvestable fruit and other foods, thus sustaining communities in arid regions. This passive use of water focused on nurturing crops through controlled distribution. Over time, however, human innovation recognized water’s potential as a dynamic force. In other words, using not just the nurturing properties of water, but the force of it as it moved. In medieval England, waterwheels transformed river currents into mechanical power, driving millstones to grind grain, as seen in the monastic millhouse where precise sluice adjustments optimized production, alleviating manual labor. Further advancement is evident in the Netherlands’ polder mills, where water’s kinetic energy was employed to pump excess sea water from low-lying fields, reclaiming arable land from briny swamps to support agriculture. This progression—from irrigation to milling to land reclamation—reflected a growing mastery over water’s mechanical potential, fundamentally reshaping labor, land use, and societal resilience in premodern Europe. Humanity knew how to use waters life-giving properties, and had now learned how to use water as energy – to do work, thus saving manual labour, freeing people to other tasks.
The Late Age of Enlightenment
Marie-Claire Montel looked about her late fathers vineyard, in Annonay, a little village in southern France. The vineyard lay warm beneath the late afternoon sun, it’s terraces rising in green, orderly steps towards a farmhouse by the woods. Below, down a gently sloped hill was the brook, flowing as it had for generations of her kin before. Until this year, watering the thirsty vines required the hauling of bucket after bucket of water up the well worn path from the waters edge. It was laborious, and tedious work. But earlier this year, something changed.
At the waters edge was a curious piece of engineering – a device of brass, oak and iron, one part in the water and part above, connected by pipes climbing the slope to a wooden storage tank at the top of the hill. The contraption clacked and hissed as a brass valve opened and slammed shut, rhythmically, almost as music.
What was it her husband Maurice had called it? She tilted her head until the name came to her – ‘le belier hydraulic’ – the hydraulic ram. That was it! It was a contraption dreamed up by a paper maker called Montgolfier. She marvelled at how it worked, that the brook’s flow slammed a valve shut and shomehow that sharp movement sent a part of the waterflow uphill. He said it was “water lifting itself”.
Now she could still tend to the vines and also still have time to take care of her children and other tasks, without having to climb the hill several times a day, without summoning anyone’s strength other than that of the waters flow. She knew that it made her life so much easier. She looked at the crazy collection of wood and pipes and valves and silently uttered, “Merci”, unsure whether she thanked the machine, the fellow who thought it up, or the water itself.
In the late 1770’s, Joseph-Michel Montgolfier was thinking about water for his paper mill. He needed a reliable supply, but his mill sat above the natural water supply and needed significant human and animal labour to get it there – both costly and not always reliable. He had earlier observed that when he shut a valve suddenly carrying water downhill in a pipe, that the water would slam to a stop, causing a surge in pressure. It’s what we now refer to as ‘water hammer’. We see it now as a problem, causing noise or worst case, bursting a pipe. But Montgolfier’s brilliance was with him wondering if somehow that pressure shock could be harnessed, instead of wasted.
He put that observation to paper and engineered a process where a downhill pipe feeds water through the device. A valve at the outlet opens, letting water gain speed. Once at a certain speed, the valve slams shut and that sudden stop creats a pressure spike that forces a small portion of the water through a check-valve, into an air chamber. The compressed air moves that water uphill through a smaller delivery pipe. The cycle repeats automatically, creating the characteristic ‘clack-hiss-thud’ every few seconds.
The practical utilization of the device spread through France, then Europe, and across the globe, enabling the use of water for industry and irrigation for crops and animals in a way that canals and aqueducts could not do – uphill. As we learned more about the physical properties of water, we were able to use human ingenuity to use those properties to our own advantage. The passive use of water’s properties continued to evolve through engineering uses, for the benefit of all.
The Medieval Era Resources
1.) Going With The Flow: A Historical Journey Through Watermills In The UK
2.) Land Reclamation In The Netherlands
3.) Spain, Facing A Future Of Drought, Turns To Medival Solutions
The Late Age Of Enlightenment Resources
1.) History Of The Hydraulic Ram
2.) Hydraulic Ram
