purree

The balls came to Europe brown on the outside and gold within, the size of a fist, and they stank. You broke one open and the inside was the yellow of held light — the yellow Turner reached for when he wanted a sky to look lit from behind. It was sold as Indian Yellow. The traders called the raw stuff purree. Nobody in the London colour houses asked too closely where it came from, and the men who made it were not in a hurry to tell.

Here is where it came from. In Mirzapur there were cattlemen who fed their cows mango leaves and nothing else, and no water to speak of, and collected the urine in earthen pots. They cooled it, boiled it down, strained the sediment through cloth, pressed it into balls, dried them over charcoal and then in the sun. The cows got sick. Mango leaves alone will do that — the kidneys can’t keep up, the animal goes jaundiced, which is to say the animal turns the same colour on the inside that the paint turns on the canvas. The brilliance and the illness were one chemistry. The pigment was the sickness, dried and shipped. Turner painted sunlight with it.

In 2002 a woman went to Mirzapur to find the cows and found nothing. No ban in the archives. No grandfather who remembered the smell. She decided the whole thing was a joke — that some clever person in the nineteenth century had told the credulous English that their luminous yellow was boiled out of tortured cattle, and watched them write it down, and that the cattle had never existed. A good theory. The English will believe anything about India if it’s lurid enough, and the men of Mirzapur knew it. Taking the piss, she said, and you could hear the pun land.

But the balls were still in a drawer at Kew. Mukharji had sent samples in 1883 along with his account, and the account got doubted and the samples just sat there, brown and gold and rank, for a hundred and thirty years. In 2016 someone put them under a Raman laser. Hippuric acid: urine. Euxanthic acid: the mango-leaf metabolite, the exact compound a cow’s body makes when it can’t finish digesting the only thing it’s been given to eat. The joke was true. The cows were real. The proof had been in the matter the whole time, outlasting the men who made it and the woman who doubted it and the empire that bought it by the thousandweight.

They make the colour in a factory now. Same hue, no cow. The tube still says Indian Yellow — a name pointing at an animal that no living paint has ever touched, a fossil of a smell. You can buy it anywhere. It’s the cleanest yellow you’ll ever ruin a sky with.