The Works of Galileo

First Two Printed Works

First printed work: The Compass

Galileo’s first printed book was a manual on the operation of a geometrical and military compass (Figure 1) . Publication was intended to please young Cosimo II, son of the Grand Duke of Tuscany, whom Galileo had tutored in mathematics the previous summer. Galileo proudly noted on the title page that he himself was a Florentine.

The instrument contained scales of his own innovative design, useful for an astonishing variety of calculations in the field (Figure 2) . For example, one could use it to estimate altitudes; in topographical surveying; to lay out military fortifications; to aim a cannon at the correct angle to achieve a target distance; or to calculate the needed diameter of a cannonball if made of brass instead of iron. Galileo had the instrument made in his own home, and supplemented his income by teaching young gentlemen how to use it.

The Oklahoma copy of Galileo’s first printed work contains his own marginal notes, including corrections which were quickly incorporated into subsequent issues of the first printed edition (Figure 3) .

“The opportunity of dealing with many great gentlemen in this most noble University of Padua, introducing them to the mathematical sciences, has by long experience taught me that not entirely improper was the request of that royal pupil who sought from Archimedes, as his teacher of geometry, an easier and more open road that would lead him to its possession; for even in our age very few can patiently travel the steep and thorny path along which one must first pass before acquiring the precious fruits of this science.... Hence I excuse them [who cannot take the long path] together with that young King of Syracuse, and desiring that they should not remain deprived of knowledge so necessary to noble gentlemen by reason of the length and difficulty of ordinary roads, I fell to trying to open this truly royal road -- for with the aid of my Compass I do that in a few days, teaching everything derived from geometry and arithmetic for civil and military use that is ordinarily received only by very long studies.” English translation Stillman Drake, Operations of the Geometrical and Military Compass (Dibner Library Publication, Smithsonian Institution, 1978).

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Galileo, 1606. Title page.

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Figure 2 Figure 2 - Return to Text

Galileo, Compass. From the 1635 edition.

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Figure 3 Figure 3 - Return to Text

Galileo, 1606. Page 12.

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Exhibit credit: Kerry Magruder, with the assistance of , Marilyn B. Ogilvie, Duane H. D. Roller.

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These teaching resources provided by the History of Science Department at the University of Oklahoma.

Unless otherwise indicated, all images courtesy History of Science Collections, University of Oklahoma Libraries. Image Terms of Use.

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