Why Call It a Witch?

Witch of Agnesi

Guest Post by Ian Stewart

Maria Agnesi was born in 1718 and died in 1799. She was the daughter of a wealthy silk merchant, Pietro Agnesi (often wrongly said to have been a professor of mathematics at Bologna), and the eldest of his 21 children. Maria was precocious, and published an essay advocating higher education for women when she was nine years old. The essay was actually written by one of her tutors, but she translated it into Latin and delivered it from memory to an academic gathering in the garden of the family home. Her father also arranged for her to debate philosophy in the presence of prominent scholars and public figures. She disliked making a public spectacle of herself and asked her father for permission to become a nun. When she refused, she extracted an agreement that she could attend church whenever she wishes, wear simple clothing, and be spared from all public events and entertainments.

From that time on, she focused on religion and mathematics. She wrote a book on differential calculus, printed privated around 1740. In 1748 she published her most famous work, Instituzioni Analitiche ad Uso Della Gioventu Italiana (Analytical Institutions for the Use of the Youth of Italy). In 1750 Pope Benedict XIV invited her to become professor of mathematics at the University of Bologna, and she was officially confirmed in the role, but she never actually attended the university because this would not have been in keeping with her humble lifestyle. As a result, some sources say she was a professor and others say she wasn't. Was she, or wasn't she? Yes.

There is a famous curve, called the "witch of Agnesi"....The curve looks remarkably unlike a witch--it isn't even pointy.

From the book Professor Stewart’s Cabinet of Mathematical Curiosities by Ian Stewart. Excerpted by arrangement with Basic Books, a member of the Perseus Books Group. Copyright © 2009.

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  1. I'm glad to see you did not repeat the common myths about Maria Gaetana Agnesi. But you don't explain here how the name "witch of Agnesi" was due to an incorrect translation. This is especially ironic because, in addition to her math skills, Agnesi was also fluent in seven languages. Unfortunately, English was not one of them.

  2. Carmela:

    I now notice this was a guest post. It did appear rather incomplete to me. Dr. Tucker gathers the most fair historical accounting and deliver them so elegantly. When I clicked on post thought I'd find author demystify for those not versed in accurate Italian history, the wonder behind naming of Agnesi's curve.

    Very good comment. Brava Carmela!


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