Squaring the circle: a collection of 19th-century mathematical texts by Francesco Cavalli.
Squaring the circle: a collection of 19th-century mathematical texts by Francesco Cavalli, Bodleian Library Vet. F6 e.173

This volume contains a collection of printed and manuscript items relating to one man’s quest to solve the mathematical problem of squaring the circle. The challenge of constructing a square with the same area as a given circle using ruler and compass and a finite number of steps is an ancient one, but was finally proven to be impossible in 1882.

The collection reveals the author’s obsession with the problem, his apparent solution, and his quest for recognition in a world that appears not to have taken him seriously. Other than a connection with Bergamo, and the suggestion that he is a priest, we have no biographical information about the author, and his name Francesco Cavalli is perhaps a pseudonym, as he also uses “Sacerdos Franciscus de Caballis”, possibly with reference to the physician, astrologer and Professor of Medicine at Padua of the same name, who died in 1540.

The items, many of which are single sheets, or multiple editions of short works, range in date from 1830-1835, and are printed mostly in Milan. The contents vary from verses in Latin about justice, recognition, and truth (relating to the sense of injustice Cavalli expresses at the world ignoring his supposed solution), engraved geometrical diagrams and proofs, to gambling games to be played with dice, and instructive works that emphasize the importance of learning mathematics by practice rather than by theory. The collection also contains manuscript letters to and from the Istituto delle scienze ed arti in Milan, regarding Cavalli’s supposed solution, his request for a prize and recognition, and the Institute’s demands for written proof of the solution. The Institute was not alone in not taking him seriously.

Item (15), written by Cavalli under the pseudonym il Muto dell’Accia al collo di Pavia, records the author’s fall from favour in the preface, and is a sarcastic response to a letter written by a rival during the 1831-32 carnival, perhaps Gli ultimi giorni del Carnovale 1832 a Milano ossia, ecco la mia opinione intorno a tutti gli spettacoli dati alla Scala … : seconda lettera dell’uomo di pietra di Milano al muto dell’accia al collo di Pavia (Milano; Bonfanti, 1832). The response includes scathing verses about the rival with the title “Biografia d’un bevitore” (Biography of a boozer). Item (18) shows Cavalli advertising a public demonstration of his solution, and item (30), which is not by Cavalli, regards a prize offered by the Lombardo-Venetian Kingdom for research into the ill effects on health of air and of drinking water.

Many of the items contain manuscript notes and diagrams, and diagrams and illustrations have been pasted onto blank spaces, including a portrait of a man who is perhaps the earlier Francesco Cavalli. The printed items are not recorded elsewhere, and present some bibliographical problems. The presence of printed wrappers bound with some items cause some confusion over whether particular items are separate bibliographical entities, or parts of larger collected works, where the works enclosed by the wrappers do not correspond exactly with the contents printed on the wrappers themselves. The manuscript items in the collection have been separately electronically catalogued by Western Manuscripts, under the category “Manuscripts in Printed Books”.

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