X-ray evidence of Black maths scholar portrait reveals snubbed genius

It was painted to celebrate the groundbreaking achievements of a mathematical genius who was Black and had been born into slavery. But for more than 260 years, that great scientific intellect of Francis Williams went unnoticed.

Now, clues exposed by an X-ray and high-resolution scans of the painting have finally revealed the extraordinary secret that 18th-century advocates of slavery sought to keep hidden.

New evidence uncovered by a Princeton historian, Prof Fara Dabhoiwala, indicates that the painting is the earliest example in western art of a named Black person celebrating their status as an intellectual.

The portrait of Williams, a wealthy Jamaican polymath who was freed from slavery as a child, was bought by the furniture curator of the Victoria and Albert Museum in 1928, primarily because it depicted fine mahogany furniture.

It has long been mistaken for a satirical painting that mocks its Black subject for having the temerity to pretend to be a Georgian gentleman and scholar. But it is now thought to have been commissioned in 1760 by Williams himself to immortalise his brilliance as a trailblazing astronomer who, the clues in the painting suggest, successfully managed to compute and witness the trajectory of Halley’s comet over Jamaica in 1759.

This dazzling mathematical breakthrough, which vindicated Edmond Halley’s predictions in 1705 about when the comet would reappear and proved Isaac Newton’s universal theory of motion and gravity for the first time, was solely credited to white astronomers who observed Halley’s comet elsewhere .

It is only thanks to the newly uncovered evidence hidden in the painting that Williams – who was proposed as a fellow of the Royal Society at a meeting Newton and Halley attended in 1716, but was later rejected by a small committee “on account of his complexion” – can finally assert his place as a pioneering Black intellectual in the history of science.

When Dabhoiwala realised that a scan of the painting revealed new titles in the bookcase, he was able to date the painting to around the time of the comet, decades after it was previously thought to have been painted.

Dabhoiwala also discovered the significance of the page number carefully inscribed on the book Williams is reading: it is the page in the third edition of Newton’s Principia that discusses how to calculate the trajectory of a comet by reference to the constellations around it.

An X-ray of the window scene depicted in the background of the painting showed lines intersecting what appears to be a luminous white comet, streaking through the sky at dusk, and connecting – with stunning accuracy – to constellations of stars. These stars would have been visible in that position in the firmament when Halley’s comet was in the sky over Jamaica in 1759, according to research by Dabhoiwala.

“I think this painting is making a really powerful statement,” said Dabhoiwala, who is giving a public lecture at the V&A on Wednesday evening about his findings, which will also be published in the London Review of Books . “It’s saying: ‘I, Francis Williams, free Black gentleman and scholar, witnessed the most important event in the history of science in our lifetimes, the return of Halley’s comet. And I calculated its trajectory, according to the rules of the third edition of Isaac Newton’s Principia’.”

He said the comet’s reappearance was “immensely important to all educated, intellectual people around the western world at this time. Everyone is waiting for Halley’s comet because it will prove that Newtonian science – modern science – works, that everything is affected by gravity, that we have figured out the universal principle at the heart of the universe … But it also has a deeply personal resonance for Francis Williams, because probably no one else outside Europe was still alive who had met and conversed with Halley and Newton. They’ve all died.”

Instruments for drawing and making complex mathematical calculations are depicted on the table in front of Williams. “I think that’s showing that he’s been doing that,” said Dabhoiwala.

By 1759, Williams had inherited a large estate in Jamaica, including plantations and enslaved people, from his formerly enslaved African father. After setting up a school for young, free Black people, he died childless in 1762. Nothing he wrote about his intellectual endeavours has ever been found. “He is a Black man in a white supremacist society. No one thinks it’s worth preserving anything by him,” Dabhoiwala said.

His portrait was sold to the V&A by the descendants of Edward Long, a white plantation owner and historian who, along with the Scottish enlightenment philosopher David Hume, had mocked Williams’ intellect in print, lending credence to the idea that the portrait must have been satirical.