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

Clues in painting suggest Francis Williams successfully managed to compute and witness trajectory of Halley's comet over Jamaica in 1759

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.