The "Witch of Agnesi"

Back in 2014, I shared a post about an animated Google Doodle in honor of Maria Gaetana Agnesi's birthday that year.The Doodle appears to represent a curve that bears the odd name "witch of Agnesi." Many books and websites say Maria "invented" the curve, but that's a myth. While Maria does discuss the curve in the mathematics textbook she wrote, the fact is that the curve had already been studied by other mathematicians before her. One of those mathematicians, Guido Grandi, had used the term versiera to describe it.

The name "Witch of Agnesi" was invented by Cambridge University mathematics professor John Colson when he translated Maria's math textbook from Italian into English. Colson gave the book it's English title: Analytical Institutions. Unfortunately, when Colson translated Maria's description of the curve, he apparently confused “la versiera” with “l’avversiera,” which means “wife of the devil.” Because of this mistake, Colson named the curve the “Witch of Agnesi” and that's how it's been known ever since. 

Maria, who was devoutly religious, would be horrified at the name!