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Galileo, Il Saggiatore (Rome, 1623), 1st ed., early state.

The Assayer

The crest of the Barberini family, showing three busy bees, appears at the top of the frontispiece. Galileo’s supporter, Cardinal Maffeo Barberini, had become Pope Urban VIII. The election of Barberini seemed to assure Galileo of support at the highest level in the Church. The book was dedicated to the new pope.

This work, long appreciated as a literary masterpiece, contains Galileo’s famous statement that mathematics is the language of nature. Galileo declared that the book of nature is written in mathematical characters, and therefore requires mathematics to be properly understood. This claim might seem ironic, given the mathematical character of the arguments over stellar parallax, star sizes, retrogradation and cometary paths, but it was an eloquent argument that physics must be mathematical rather than pursued as part of a logic-based natural philosophy.

Il Saggiatore contains Galileo’s earliest published diagram of the phases of Venus and the odd appearance of Saturn as seen through his telescope.  

In this work Galileo also defended the distinction between primary and secondary qualities.  This point was central to ancient atomic theory. Particles with sharp edges (with sharpness as their objective primary quality) might be perceived by us as possessing a bitter taste (with bitterness as their subjective secondary quality.  This objective/subjective distinction therefore drove a wedge between matter as it is in itself and sensory perception.  From a modern perspective, the distinction between primary and secondary qualities might lead one to say that science advances by the progressive denial of the reality of common sensory perception.

This copy is a rare first state of the work, perhaps the first copy printed. It was formerly owned by Stillman Drake, a Galileo scholar who edited Galileo’s scientific manuscripts.

Galileo's World Exhibition Location

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