London Calling. London Walks connecting.
This is London. This is London Walks.
Streets ahead,
Story time. History time.
Put your hand up if you’ve ever had your blood pressure taken.
Actually, don’t bother.
Pretty much all of us have.
That cuff goes round your arm.
It tightens.
Squeezes.
Perhaps you look away, pretending not to care about the number that’s about to appear.
And standing invisibly beside you is an eighteenth-century clergyman from Teddington.
Stephen Hales.
Never heard of him?
That’s rather the point.
Because Stephen Hales was born on this day, September 17th, 1677.
And if you’ve ever had your blood pressure taken, if your doctor has ever muttered something about hypertension, if you’ve ever watched those numbers appearing on a little screen…
Stephen Hales is the ghost at that banquet.
He’s there.
Looking on.
Present.
Because Stephen Hales was the first person to measure blood pressure.
And when I say measure blood pressure, forget the neat little cuff.
Forget the digital display.
Forget the reassuring nurse saying, “Just relax your arm.”
This was 1733.
There was a horse.
There was an artery.
And there was a very long glass tube.
We’ll come to that.
But first, Teddington.
Because Hales spent most of his adult life there, as perpetual curate of St Mary’s.
And Teddington gives us today’s word.
Or rather, part of today’s word.
Town.
There’s a wonderfully tempting explanation of Teddington.
Tide-end-town.
The place where the tidal Thames ends.
And the geography makes it irresistible.
The tidal Thames does effectively finish at Teddington.
Teddington Lock.
Teddington Weir.
Tides on one side.
Non-tidal Thames on the other.
Tide-end-town.
Perfect.
And wrong.
That’s folk etymology doing what folk etymology does best.
Seeing a lovely explanation and saying, “Oh, that must be it.”
The name is much older.
Teddington is probably the settlement associated with a man called Tudda.
Tudda’s people.
Tudda’s settlement.
And the final part of the name takes us to one of the great little workhorses of the English language.
Old English tūn.
Originally an enclosure.
Then a farmstead.
Then a settlement.
And eventually…
town.
Think about that journey.
Fence.
Farm.
Settlement.
Town.
And then think about what Londoners say.
“I’m going into town.”
And by town we mean London.
One of the greatest cities on Earth.
There’s a thousand years of linguistic inflation for you.
Anyway.
Back to Stephen Hales.
He was born in Kent, educated at Cambridge and ordained.
But there’s a nice London Walks connection tucked away in his boyhood.
Before Cambridge, young Stephen was educated by a Mr St Clare in Kensington.
Which means that somewhere in the Kensington of the 1690s, when Kensington was still hovering between village and royal suburb, one of the great experimental scientists of the eighteenth century was getting his schooling.
And almost nobody walking through Kensington today has the faintest idea.
Exactly our kind of history.
Hales eventually settled at Teddington.
And outwardly, you might have thought:
Country parson.
Church.
Sermons.
Parishioners.
Garden.
Nothing to see here.
Oh, no.
Because Hales was one of those people who looked at the ordinary world and simply couldn’t leave it alone.
How does water get up a plant?
How does air work?
What happens inside an animal?
How does blood move?
Can bad air be replaced with good air?
Can you measure these things?
Measure.
That’s the key word.
Hales didn’t just want to talk about nature.
He wanted numbers.
He wanted experiments.
He wanted to catch nature in the act.
Which brings us to the horse.
In 1733 he published his experiments on animals.
And one of them has gone down in medical history.
Hales inserted a brass tube into an artery in a horse’s leg.
To that he attached a long upright glass tube.
And then he watched.
The blood rose.
And rose.
And rose.
More than eight feet.
Think of that.
Eight feet of blood pressure made visible.
The heartbeat causing the column to rise and fall.
For the first time, somebody had actually measured arterial blood pressure.
It was ingenious.
It was historic.
And, yes, it was horrible for the horse.
We shouldn’t dodge that.
Hales experimented on living animals and there were contemporaries who were appalled by it.
Alexander Pope was one.
Pope admired Hales the man but detested what he regarded as cruelty to animals.
That tension belongs in the story.
Scientific breakthrough on one side.
Animal suffering on the other.
History doesn’t always give us nice clean packages.
But Hales’s curiosity went everywhere.
Plants particularly fascinated him.
How much water does a plant take in?
How much does it give off?
What role does air play?
How quickly does sap move?
He weighed plants.
Measured them.
Cut them.
Connected tubes to them.
Watched them breathe.
He was helping to invent plant physiology.
And then there was air.
Hales became obsessed with ventilation.
Now that sounds wonderfully unexciting.
Ventilation.
Not exactly splitting the atom.
Except think about eighteenth-century Britain.
Prisons.
Workhouses.
Hospitals.
Ships.
Packed rooms.
Packed bodies.
Stale air.
Disease.
Stench.
And very little understanding of what was happening.
Hales designed ventilators.
Machines for moving foul air out and fresh air in.
They were installed in hospitals.
Workhouses.
Gaols.
Ships.
King’s Bench Prison.
Newgate Prison.
Even the House of Commons.
Yes.
Stephen Hales tried to introduce fresh air into Parliament.
Some battles are never finally won.
His ventilators were also installed at Drury Lane Theatre.
Which is rather wonderful.
Hales was improving the atmosphere in Parliament, prisons and the theatre.
There’s a London itinerary for you.
And during wartime his ventilators were used for prisoners on both sides of the Channel.
Hales joked that nobody could accuse him of corresponding with the enemy.
His machines were helping French prisoners in England…
and English prisoners in France.
That’s rather lovely.
Practical humanity with a twinkle in its eye.
And that seems to have been Hales.
He was constantly trying to make things work a little better.
Gilbert White, the great naturalist of Selborne, remembered him with enormous affection.
And White gives us some of the most charming glimpses of Hales.
Hales worried about people drinking tea too hot.
He thought ladies’ kettles ought to be designed so the water cooled a little before it reached the cup.
He offered advice to ferrymen.
He suggested putting an inverted teacup into a fruit pie to stop the syrup boiling over.
Yes.
One of the great physiologists in the history of science…
was thinking about pie juice.
That’s my kind of scientist.
And there’s an even better one.
Near the end of his life, Hales had the tops of posts beside local footpaths painted white.
Why?
So his neighbours wouldn’t walk into them in the dark.
Gilbert White called it his “last act of benevolence.”
Isn’t that wonderful?
Not a grand scientific discovery.
Not a learned paper.
A dab of white paint.
So somebody walking home in the dark didn’t bark their shin.
Hales’s London connections kept multiplying.
He became chaplain to Augusta, Princess Dowager of Wales.
And that took him into the royal world at Kew.
He helped with plans for a huge greenhouse there, about 120 feet long.
Which makes perfect sense.
Of course the man fascinated by plants and air ends up helping create a gigantic royal glasshouse.
Plants.
Air.
Glass.
Measurement.
Kew.
All the threads come together.
And then there’s Westminster Abbey.
Because after Hales died in 1761, Princess Augusta paid for a memorial to him there.
And the inscription links him with Newton.
Now, hold on to that.
Because this is where the story becomes almost unbelievable.
Stephen Hales was not some amiable country clergyman who happened to fool around with a few tubes.
His research techniques and discoveries helped open up whole areas of pneumatic chemistry, vegetable physiology and animal physiology.
Scientists who came after him knew exactly who he was.
Joseph Black.
Henry Cavendish.
Joseph Priestley.
Lavoisier.
Humphry Davy.
Major names.
And in Britain his scientific reputation was once described as…
second only to Newton.
Let’s have that again.
Second.
Only.
To Newton.
And we’ve forgotten him.
That, for me, is the story.
Because Newton is everywhere.
Newton’s apple.
Newton’s laws.
Newton’s gravity.
Newton in Westminster Abbey.
Newton on the school syllabus.
Stephen Hales?
Who?
And yet tomorrow morning somebody in London will sit down in a doctor’s surgery.
A cuff will go round their arm.
It’ll tighten.
The machine will hum.
Two numbers will appear.
And nobody in the room will say the name Stephen Hales.
But he’ll be there.
The ghost at that banquet.
The Teddington parson who looked at the circulation of blood and thought:
Can we measure that?
And then did.
Not with electronics.
Not with a cuff.
With a horse.
A brass pipe.
And eight feet of glass tubing.
Which is perhaps the most Stephen Hales thing imaginable.
Scientist.
Clergyman.
Inventor.
Plant physiologist.
Public-health pioneer.
Pie improver.
Painter of posts.
Second only to Newton.
Born 349 years ago today.
And remembered, if nowhere else, here.
On London Walks.
Streets Ahead.
So, yes, Stephen Hales. Bet that one caught you off guard didn’t it.
But be honest. It’s one reason some of you touch down here. Quite often, right here, a new planet comes swimming into your ken. And if there were two of you you’d look at each other with a wild surmise.
London Walks doing its thing.
See you tomorrow.