Baldassarre Capra

Background

Capra was born in 1580, in Milan, Italy, the son of Aurelio Capra and Ippolita Della Croce. Baldassarre came from a family of the ancient nobility but somewhat reduced circumstances. His father was an amateur doctor.

Education

In 1594 Capra's family moved to Padua so that Baldassarre could study medicine, astronomy and mathematics. To support them, Marco Aurelio gave fencing lessons. One of his students was Galileo himself, introduced by their mutual acquaintance Giacomo Alvise Cornaro.

Career

Capra’s father entrusted his son to Simon Mayr, a teacher from abroad, who Latinized his surname to Marius and, coming from Prague, boasted of having studied under Tycho Brahe and Johannes Kepler (even though he had stayed in that city for less than a year). Mayr’s influence on Capra and on his works is evident not only in the work published in the year of his departure but also in the subsequent ones, which certainly had been begun before he left Italy.

Capra’s first work, published in Padua in 1605, is perhaps the one of greatest interest and value. It is written in Italian, for which he apologizes in the dedication to his maternal uncle, Giovanni Antonio Della Croce. Capra maintains, against the Aristotelian thesis, that the new star belongs to the sphere of fixed objects and gives ample and precise information on its position and the variations of its color and its size, demonstrating that he made careful observations. At the end, there is an attempt at an astrological interpretation, which should not be surprising since astrology was still popular. In very bad taste are the frequent taunts at Galileo, on secondary questions and often with an air of pretext, almost as if the author was looking for controversy. For the time being, however, Galileo did not feel it necessary to answer, nor did he wish anyone else to do so. In 1606, in Padua, Capra published two booklets in Latin, both dedicated to Cardinal Federigo Borromeo and each consisting of fourteen pages. Modest also in their content, they were entitled Tyrocinia astronómica, in which Capra prudently appeals as much to the authority of Tycho Brahe as to that of Ptolemy, and Disputationes duae, una de lógica et eius parlibus, altera de enthymemale.

The work to which he devoted the greatest effort and the most diligence, Usus et fabrica circini cuiusdam proportionis, per quern omnia fere turn Euclidis, turn mathematicorum omniumproblematafacili negotio resolvuntur, consisting of fifty-six pages with numerous woodcuts and one copperplate on the title page, was published at the beginning of 1607 but was probably the result of several years of work, even though it shows very little originality. The work is dedicated to Joachim Ernest of Brandenburg, to whose court Simon Mayr had returned after completing his studies. Because of the close analogies with Galileo’s II compasso, which had appeared a few months before, this book was clamorously condemned to sequestration and destruction, but for the same reason it was fully analyzed by Galileo’s students and included in all editions of his works, beginning with the one published at Bologna in 1655.

To all that has been said on this subject, it is possible to add that probably Capra, while his teacher was still in Padua, had set out to give greater authority (by putting them in Latin) to the handwritten instructions on use of the compass that had been publicly dictated by Galileo but generally were circulated in the “adespota” form (anonymously), which meant they were both without author and without owner. This at least explains the imprudent and foolish attempt by Capra, who, if he had only cited his source and renounced the absurd pretext of priority, would have had both fame and advantage, including economic benefit, from that work. That unfortunate attempt was instead his ruin. Having left Padua quite precipitously, he apparently returned to Milan, where he kept in contact with the anti-Galileans, including Horky; but at the end of 1620, when he asked to register at the medical college of Milan, Lodovico Settala energetically opposed him because of his behavior toward Galileo. There is no further news of him until his death, which came shortly after his forty-fifth birthday, on May 8, 1626.

Achievements

• Capra is known today only because he was one of the first opponents of Galileo, whom he attacked unjustly in 1605 regarding his observations on the new star which had appeared the year before, and whom he gravely offended two years later by plagiarizing the first book Galileo submitted for publication. He published as his own a brief Latin treatise on the proportional compass, which proved to be scarcely more than a translation of Galileo’s Le operazioni del compasso geométrico e militare, a translation not without defects and, in addition, sprinkled with malevolent insinuations against the real author.

Works

More photos

• book

  • Usus Et Fabrica Circini Cuiusdam Proportionis: Per Quen Ferè Tum Euclidis, Tum Mathematicorum Omnium Problemata Facili Negotio Resoluuntur

    (Latin Edition)

    1655

Connections

Father:

Aurelio Capra

Mother:

Ippolita Della Croce

References

• Dictionary of Scientific Biography Volume 3
  1971
• Notizie Istoriche Intorno A'medici Scrittori Milanesi E A'principali Ritrovamenti Fatti In Medicina Dagl'italiani Italian Edition
  1718
• Bibliotheca Scriptorum Mediolanensium
  1745