Nevil Maskelyne: The Man Who Weighed the World
London calling.
London Walks connecting.
This… is London.
This is London Walks.
Streets ahead.
Story time. History time.
Top of the morning to you, London Walkers.
Wherever you are.
And here we go, here’s your daily London fix.
It’s Monday, February 9th.
And on this day in 1811,
at the Royal Observatory in Greenwich,
one of the quiet giants of
British science dies
among his clocks, his tables, and the orderly heavens he spent a lifetime taming.
His name was Nevil Maskelyne.
He was the fifth Astronomer Royal.
He held the office
from 1765 to 1811,
an extraordinary 46 years.
Longer than anyone else before or since.
And during that long, patient watch he did something audacious, eccentric, and profoundly Enlightenment in spirit.
He weighed the world.
And for good measure,
he made the world run on Greenwich time.
Let’s rewind.
Maskelyne was born in Kensington Gore in October 1732.
A London childhood.
Westminster School.
A family that starts comfortably enough and then collapses.
His father dies when Nevil is eleven.
His mother follows soon after.
The safety net vanishes.
What remains are scholarships, intellect, and grit.
At Westminster he decides,
early and decisively,
that astronomy is the thing.
That means mathematics.
Serious mathematics.
So it’s Cambridge.
He goes up as a sizar –
a bright student without money, studying on support rather than privilege.
He works ferociously,
migrates colleges,
and emerges seventh wrangler – seventh in the ferociously competitive Cambridge mathematics rankings.
Not top of the list, but high enough. High enough for Trinity College,
a fellowship,
and a foothold in the scientific establishment.
Like many ambitious young men of the period, he takes holy orders.
Not out of burning pastoral zeal,
but because the Church is the ladder.
It pays, it feeds,
and it leaves nights free for telescopes.
Maskelyne has bigger fish to fry.
Longitude.
The great unsolved problem of the age.
Latitude is easy.
Longitude kills.
Get it wrong and ships wreck,
fleets vanish, and
empires haemorrhage men and money.
Parliament is so desperate it has offered a fortune for a solution.
Maskelyne believes the answer is written in the sky.
In 1761 he sails to St Helena to observe the transit of Venus.
It’s an international scientific effort. Astronomers scattered across the globe,
all watching the same tiny black dot crawl across the face of the sun. Except the sun refuses to cooperate. Clouds roll in.
Venus disappears.
The experiment fails.
But Maskelyne does not come home empty-handed.
On the voyage he experiments with the lunar distance method.
Using the moon as a moving clock. Measure its position against the stars,
compare it with published tables, and you can calculate
your longitude anywhere on Earth. It’s demanding,
mathematical, and fiddly.
But it works.
Back in Britain he publishes The British Mariner’s Guide.
Clear. Practical.
Written so sailors can actually use it.
That matters.
Then comes the episode that earns him enemies.
He is asked to help assess
John Harrison’s famous timekeeper, the longitude watch.
The popular legend casts Harrison as the wronged genius and Maskelyne as the obstructive villain.
The reality is less melodramatic
and more bureaucratic.
Maskelyne is a public servant.
He insists on standards, verification, and repeatability.
He does his job.
And for that, he’s resented.
In February 1765,
his life changes overnight.
The Astronomer Royal dies. Maskelyne is appointed.
And he moves into the Royal Observatory at Greenwich.
From this moment on,
Greenwich becomes the engine room of global navigation.
Maskelyne works relentlessly.
Night after night.
Moon crossings.
Star positions.
Planetary movements.
Tens of thousands of observations, all logged,
checked, and above all published. His predecessors had gathered data. Maskelyne shares it.
And then he does the thing that defines his legacy.
He creates the Nautical Almanac.
An annual publication telling sailors exactly where the sun, moon, and stars will be,
day by day, hour by hour.
With it, the lunar distance method becomes teachable and reliable. Greenwich becomes the world’s reference point not by royal decree, but by usefulness.
Then, in 1774,
Maskelyne does something gloriously strange.
He goes to Scotland
to weigh the Earth.
At a mountain called Schiehallion, he measures
how the mass of the mountain
pulls a plumb line slightly off vertical.
From that minute deviation he calculates the density of the entire planet.
He concludes that the Earth is about four and a half times denser than water.
Modern measurements put it at 5.52.
Not bad for a plumb line,
a telescope, and a mountain.
He weighed the world.
And for good measure, he made the world run on Greenwich time.
Still, he does not slow down.
He edits forty-nine issues of the Nautical Almanac himself.
He plans scientific observations for voyages of exploration.
He supports Cook, Vancouver, and Flinders.
He times eclipses,
tracks comets,
measures Uranus,
and keeps Greenwich running like a celestial factory.
He marries late, becomes a father, and retreats each autumn to a modest country cottage.
And then, in January 1811,
after attending meetings almost to the end, he falls ill.
On Monday, February 9th, 1811, Nevil Maskelyne dies at the Royal Observatory, Greenwich.
He’s buried quietly in Wiltshire.
But his legacy ticks on.
Every time a ship knows where it is.
Every time the world agrees what time it is.
Every time Greenwich means something.
That is Maskelyne’s doing.
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It’s not rocket science: you get what you pay for.
And just as surely, you also get what you don’t pay for.
Back in 1968 when we got started we quickly came to a fork in the road. We had to answer a searching question: Do we want to make the most money? Or do we want to be the best walking tour company in the world?
You want to make the most money you go the schlubbers route. You want to be the best walking tour company in the world you do whatever you have to do to attract and keep the best guides in London – you want them guiding for you, not for somebody else.
Bears repeating: the way we’re structured – a guides’ cooperative – is the key to the whole thing.
It’s the reason for all those awards, it’s the reason people who know go with London Walks, it’s the reason we’ve got a big following, a lively, loyal, discerning following – quality attracts quality.
It’s the reason we’re able – uniquely – to front our walks with accomplished, in many cases distinguished professionals:
By way of example, Stewart Purvis, the former Editor (and subsequently CEO) of Independent Television News.
And Lisa Honan, who had a distinguished career as a diplomat (Lisa was the Governor of St Helena, the island where Napoleon breathed his last and, some say, had his penis amputated – Napoleon didn’t feel a thing – if thing’s the mot juste – he was dead.)
Stewart and Lisa – both of them CBEs – are just a couple of our headline acts.
Or take our Jack the Ripper Walk. It’s the creation of the world’s leading expert on Jack the Ripper, Donald Rumbelow, the author of the definitive book on the subject. Britain’s most distinguished crime historian, Donald is, in the words of The Jack the Ripper A to Z, “internationally recognised as the leading authority on Jack the Ripper.” Donald’s emeritus now but he’s still the guiding light on our Ripper Walk. He curates the walk. He trains up and mentors our Ripper Walk guides. Fields any and all questions they throw at him.
The London Walks Aristocracy of Talent – its All-Star Team of Guides – includes a former London Mayor. It includes the former Chief Music Critic for the Evening Standard. It includes the Chair of the Association of Professional Tour Guides. And the former chair of the Guild of Guides.
It includes a former Member of Parliament, three terms at Westminster, bringing first-hand experience of power, policy and political theatre to the very streets where it all played out.
It includes two barristers, three doctors, two geologists, a distinguished museum curator and a former Time out Editor.
It includes authors, historians, national journalists, a former London Museum archaeologist, and university professors (one of them an eminent Cambridge University paleontologist).
It includes a criminal defence lawyer, Royal Shakespeare Company and Royal National Theatre actors, and two professional photographers. And last but not least, the creme de la creme of top flight professionally qualified Blue Badge Guides, including a bevy of MVPs, Oscar winners (people who’ve won the big one, the Guide of the Year Award)… well, you get the idea.
As that travel writer famously put it, “if this were a golf tournament, every name on the Leader Board would be a London Walks guide.”
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And here’s the clincher. We’re playing at home.
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And on that agreeable note… come then, let us go forward together on some great London Walks.
And that’s by way of saying, Good walking and Good Londoning one and all. See ya next time.