Early Astronomy in the University of Michigan Collections

The publication of Grassi’s Libra astronomica ac philosophica compelled Galileo to publish a more substantial treatise on the scientific method, going far beyond the discussion on the nature of comets: Il Saggiatore nel quale con bilancia esquisita e giusta si ponderamo le cose contenute nella Libra astronomica e filosofica de Lotario Sarsi Sigensano (The Assayer, in which the Matters Discussed in the Astronomical and Philosophical Books by Lotario Sarsi of Siguenza are Weighed with Exquisite and Right Balance).

The carefully designed content of the engraved title page reveals not only the purpose of Galileo’s work but also some of the political circumstances in which it was published. Galileo’s strong criticism of Grassi’s Libra astronomica is anticipated by the choice of the title, Il Saggiatore (The Assayer). Indeed, the word assayer, a finely calibrated scale used by the goldsmith to weigh precious metals, was meant to be a playful criticism of the rougher Libra (Weighing Scales) in the title of Grassi’s work. Moreover, the ambitious scope of Il Saggiatore is illustrated by the two female figures on both sides of the engraving: they represent Natural Philosophy and Mathematics, signifying the disciplines of physics and mathematics as the pillars of the scientific method. In terms of politics, the coat of arms of the Barberini family (the three bees) suggests the implicit endorsement of the new Pope Urban VIII, formerly Cardinal Maffeo Barberini. Dedicated to the new pope, Il Saggiatore was published under auspices of the Lincean Academy: see the symbol of the lynx at the bottom of the page.

Our copy includes the ownership inscription, Pauli Manfredi. A possible candidate behind this signature is Paolo Manfredi (1640-1716), who was a professor of medicine at the University of Rome. Though Manfredi wrote several medical treatises, he is best remembered for his research on blood transfusion: he successfully injected calf’s blood into a man in January 1668, six months after this procedure was first achieved in Paris.

Il Saggiatore: Engraving

Galileo