An image of Ben Franklin with the Lake District in the background

Benjamin Franklin's Scientific Adventures in the Lake District

Did you know that Benjamin Franklin visited the English Lake District?

The American scientist, printer and statesman made a noteworthy trip to the region in 1772 – 250 years ago – and he was wowed by the experience. Being a man of irrepressible curiosity, he was hardly an idle tourist. He explored the wonders of the region from top to bottom with two of the other eminent scientists of his era, Sir John Pringle and Dr William Brownrigg. These men of science even found time to conduct an influential experiment that involved pouring olive oil into Derwent Water. This autumn, we set out to recreate that experiment as part of Being Human 2022.

Below you'll find a video about the history of Franklin's experiment as well as a series of galleries. You can scroll through each gallery by using the chevrons to the right of the thumbnail images.

Transcript for Oil on Water

Why does oil calm troubled waters? That question has long piqued peoples’ curiosity. Today, we know the answer, but the phenomenon puzzled scientists for centuries.

It certainly intrigued people in the ancient world. Two thousand years ago, writers like Pliny the Elder (the Roman scholar and statesman) noted that divers sometimes took to the sea with a mouth full of olive oil, which they’d release bit by bit to calm the waves above them. Apparently, they did that so the sun would shine more steadily through the water and help them see.

Oil and water won’t mix, at least not for long under most circumstances. That’s because of the way oil and water molecules are composed. All molecules are made of atoms, and atoms have different electrical charges. They can be positive, negative or neutral. Those charges effect the way molecules behave.

Water is made up of an oxygen atom and two hydrogen atoms (which is why water is sometimes called H₂O), and it’s what’s called a polar molecule. In a nutshell, that means that it has different electrical charges at each of its ends. The oxygen atom has a negative charge, whereas the two hydrogen atoms have positive ones.

Oil molecules are different. They’re usually made up of nonpolar chains of carbon, oxygen and hydrogen atoms, which are linked in ways that spread the positive and negative charges out evenly.

The upshot of all that is that water molecules are more attracted to each other than they are to oil molecules, and oil molecules are the same. They like to stick together. If you’ve ever tried to wash grease off a skillet without using soap, you’ll have experienced that first hand.

But how does that help us explain why oil can still waves?

The answer has a lot to do with density. Oil molecules are larger than water molecules. They can’t press together as tightly as water molecules. That’s why when oil and water separate, the oil rises to the top. Once at the top, the chains that make up oil molecules link together, forming a film over the water’s surface. If given enough room, that film will stretch out as far as the linked chains will let it, which is why even a teaspoon of oil can form a slick that’ll cover dozens of square feet. That’s why the divers Pliny described carried olive oil with them when they went to work.

We wouldn’t have such a firm grasp of molecular forces if it weren’t for inventions like the electron microscope. In the days before scientists had such tools, studying the interaction of oil and water was a practical way of investigating the way molecules behave and understanding their science. And questions about the interaction of oil and water were of great interest to one of the leading scientists of the 18th century, the American founding father, Benjamin Franklin.

Franklin got interested in the subject while on board a ship. He was travelling in a fleet, and he noticed that the water around two of the ships was much calmer than around the others. When he asked his captain why, he was told that the ships’ cooks had just tipped the ‘greasy water’ out of their pots and pans.

Franklin was intrigued by this explanation. It put him in mind of the divers Pliny had described, and he set out to study the phenomenon himself. He even ended up conducting an experiment that involved pouring oil into Derwent Water, in the English Lake District.

But why was Franklin in the English Lake District? Wasn’t he one of the founding fathers of the United States?

He was, but he also spent a good deal of his life in England working as a political representative. You can actually visit the townhouse where he lived in London. It’s now the Benjamin Franklin House museum. London, in Franklin’s day, was one of the world’s great centres of scientific research. It was a place where groups, like the Royal Society, were shedding new light on the forces of nature.

The Royal Society’s members knew of Franklin’s work. He was already a distinguished researcher in his own right, not least for his studies of electricity. He performed his famous kite-experiment in 1752, and he received the Society’s most prestigious award, the Copley Medal, the following year. He became a fellow of the Society in 1756.

Franklin was busy during his years in London, but he still found time to take short breaks. Sometimes, he went on trips with his friend, Sir John Pringle, who was also a fellow of the Royal Society.

It was John Pringle who arranged Franklin’s visit to the Lakes, where they called on another Royal Society Fellow, Dr William Brownrigg, who lived near Keswick. Brownrigg shared Franklin’s interest in molecular forces, and he also knew of Pliny’s description of the divers. So, one afternoon, they rowed out onto Derwent Water to see what would happen if they dropped a little oil in the lake. The experiment proved a success. In a letter Franklin wrote, he explained that the water had been ‘in great agitation’ but ‘was instantly calmed’ to a ‘great distance about the boat’ at the application of ‘only a very small quantity of oil’.

We hasten to add, of course, that Franklin wasn’t using petrol. He was likely using olive oil, which is far less hazardous. Still, we’d urge you not to recreate his experiment on your own without using proper containment equipment and checking with the appropriate authorities. The rate at which relatively benign fluids like olive oil can spread reminds us of how quickly contaminants can disperse into our water systems.

Franklin repeated his experiment on a few other occasions, and the results helped him form a theory that went on to make waves of its own. His ideas about the interaction of oil and water helped pave the way for the scientific innovations on which our knowledge of molecular physics is based. As with so many of Franklin’s contributions to the sciences, his oil on water experiment still remains very relevant to this day.

Why does oil calm troubled waters?

People have long known that oil can calm water, but even in Franklin's day the phenomenon wasn't fully understood.

Pliny's 'Natural History'

The interaction of oil and water was a subject of considerable interest in the ancient world. The Greek philosopher Plutarch wrote about the subject, as did Aristotle apparently.

In the first century, the Roman scholar and statesman Pliny the Elder recorded that divers often took to the sea with a mouthful of oil in order to calm the waves above them.

'Everything is soothed by oil', as Pliny explained.

Edition of Pliny's Natural History from 1615, © The Royal Society

Image of sailors in a boat from a medieval manuscript

Bede's 'Ecclesiastical History'

Around 700 years after Pliny's time, the great Christain historian of Northern England, Saint Bede, recorded a story in which a priest used holy oil to calm a story sea.

That might sound like a tall tale, but there's definitely some truth to it. Oil can't stop a storm, but it can help make choppy water smoother.

Even a millennium after Bede, though, the cause of this curious property of oil was still not understood.

Image from Bede's Life of Saint Cuthbert, © The British Library

Franklin's voyage to England

Franklin fist got interested in the interaction of oil and water on his voyage to England in 1757. He was in a fleet and noticed that the water around two ships was calmer than around the others. When he asked his captain why, he was told that the ships’ cooks had just tipped the ‘greasy water’ out of their pots and pans.

Franklin was intrigued by this explanation, which put him in mind of the account he had read in Pliny, and he set out to study the phenomenon.

The Ship Transit, © The Beacon Museum, Whitehaven

'I resolved to make some Experiment of the Effect of Oil on Water'

A trial on Clapham Common

Once he was settled in London, Franklin set about studying the interaction of oil and water. He devised an experiment that he first attempted on one of the ponds on Clapham Common.

On that occasion, he was astounded to observed how ‘not more than a tea spoonful’ of oil ‘produced an instant calm’ that spread over half an acre of the water.

Watercolour of the Mount Pond at Clapham (c. 1825), by Joseph Powell

Image of the cane Franklin used for his experiments

A bamboo cane

After trying the experiment on Clapham Common, Franklin began carrying oil with him in a special bamboo cane.

He wrote that he took the cane with him 'whenever I went into the Country', so he could 'repeat the Experiment as Opportunity should offer'.

A bamboo cane, supposed to have belonged to Franklin, American Philosophical Society. Gift of H. H. Harjes, 1915

Olive oil, that is...

Franklin wasn't using petrol, we hasten to add! His writings suggest that he was using olive oil.

In any case, his first attempts at the experiment allowed him to observe the behaviour of oil on small bodies of water. When he went to the Lake District in 1772, he had the perfect opportunity to try the experiment on a large lake, Derwent Water.

Three men in a boat

Benjamin Franklin

Franklin made his visit to the Lake District in 1772, when he was working in London as a political representative.

London was then one of the world’s great centres of scientific research. It was a place where groups like the Royal Society were shedding light on the forces of nature. Franklin became a fellow of the Royal Society in 1756.

White House Historical Association, Public Domain

Sir John Pringle, by an unknown artist

Sir John Pringle was also a fellow of the Royal Society, and he became one of Franklin's closest friends. The two men often travelled together while Franklin was living in England.

Pringle was the one who arranged Franklin’s visit to the Lake District in 1772.

Pringle served as the President of the Royal Society between 1772 and 1778.

Wellcome Collection, Public Domain

Dr William Brownrigg

William Brownrigg (1711—1800) was also a fellow of the Royal Society. He hosted Franklin and Pringle when they came to the Lake District in 1772.

Brownrigg was born near Aspatria, in Cumberland, and he worked for many years as a physician in Whitehaven, where he conducted experiments to improve working conditions in the town’s coalmines.

Courtesy of West Cumberland Hospital and the Beacon Museum, Whitehaven

How did the world come to know of the experiment?

Image of the letter Franklin sent to Brownrigg

A letter about 'the Keswick experiment'

We wouldn’t know about the oil on water experiment if it weren’t for the Revd James Farish, of Carlisle.

He caught wind of Franklin, Brownrigg and Pringle's doings on Derwent Water, and he asked for an account of what he called ‘the Keswick experiment’. At Brownrigg’s request, Franklin provided an explanation in a letter.

© The Royal Society

'Of Stilling the Waves'

That letter was subsequently read at the Royal Society and then published in the Society's Philosophical Transactions in 1774. From there, Franklin's account of the experiment went on to make waves of its own.

A widely read pamphlet

Franklin’s letter was soon reprinted as a pamphlet that reached a wide audience. It evidently came to the attention of the author James Boswell. He wrote to the American diplomat William Temple in April 1775 that ‘Franklin has written upon stilling the waves by oil, as I see you would quiet the turbulent Americans by lenient measures’.

A landscape of science and industry

The history of Franklin’s experiment reminds us of the connections between the Lake District and the history of science and industry. There are other local figures whose contributions to the sciences deserve attention as well. Below, we've introduced two such figures, whose life and works can be explored in greater detail by visiting Keswick Museum and the Beacon Museum.

Jonathan Otley

Otley (1766–1856) was born at Scroggs, in Langdale, and he became a notable figure in the sciences locally in the generation after Brownrigg.

In addition to publishing on geology, botany and meteorology, he also published a best-selling guidebook the Lake District.

What's more, for several years he worked in Keswick as a watchmaker, surveyor and tour guide.

An image of Otley's account of his first meeting with Dalton

Meeting John Dalton

Otley was known to many of the great scientists of his era, including John Dalton (1766–1824), who was also a Cumbrian.

Dalton came from Eaglesfield, near Cockermouth, and he went on to make several important contributions to chemistry. He is sometimes said to be the 'father of modern atomic theory'.

This manuscript contains Otley's account of his first meeting with Dalton in 1844. The two of them cross paths on the top of Skiddaw, the high mountain north of Keswick.

Carlisle Spedding

Spedding (1696–1755) was one of the more ingenious Cumbrians of his era. He was an engineer, architect and inventor, and he managed the colliers in Whitehaven from the 1730s until his death in a pit explosion in 1755.

During that time, he worked alongside Brownrigg to improve the efficiency and safety of mining operations around Whitehaven.

The two men became relatives in 1741, when Spedding's neice, Mary, married Brownrigg.

Courtesy of the Haig Pit Mining and Colliery Museum

Spedding Mill

One of Spedding's most notable inventions was the steel mill.

The mill worked by turning a handle to drive two cogs, which powered a metal wheel. A flint held against this spinning wheel produced sparks.

The mill allowed the user to notice the dangerous presence of methane gas when the sparks changed colour.

Before the Spedding mill, explosions killed or maimed hundreds of miners throughout England when candle flames came into contact with dangerous gases.

Acknowledgements

This project has received support from the AHRC through Being Human, the UK's annual festival of the Humanities. We are grateful to the festival organisers and to our cultural partners: the Beacon Museum, Benjamin Franklin House, Keswick Museum and the Royal Society.