URINE, THOUGH disdained by modern society, was once surprisingly useful stuff. Street-facing laundries in ancient Rome had pissoirs attached to them, to encourage passers-by in need of relief to provide, free of charge, a raw material which was then fermented into a degreasing agent. Urine also found employment as a mordant, to assist in the dying of cloth—Scottish tweed was once notorious for smelling of the stuff when it got wet. And urine was, too, a source of potassium nitrate, one of the ingredients of gunpowder.
This article appeared in the Science & technology section of the print edition under the headline “From Clochemerle to a compost heap”
From the January 2nd 2021 edition
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