TO THE READER.

(though he had not noticed the verses of Empedocles and a certain tragedian cited in the same place). Nevertheless, leaving Theon’s Astronomy—which he valued so highly—unpublished, the learned man preferred to print a slightly more corrected version of the Arithmetic of the same author, which Bullialdus had already edited in its entirety.

I could not gain access to the Milanese codex itself, even if it still existed. It was not easy to obtain a copy of it that could be trusted. Yet no other hope seemed to remain for me. For, during the holidays that I am accustomed to using to peruse those books in Paris that I lack in Rennes, I had approached the learned men in charge of preserving the codices at the Royal Library in October 1845. After searching the catalog, they affirmed that while many codices of the mathematical work of Theon of Smyrna—which Bullialdus published—existed, no codex of his Astronomy existed in the treasures committed to their care. How they were deceived by this catalog error will be explained soon.

However, in October 1846, while I was conversing with Félix Ravaisson, a man well-deserving regarding Aristotle and metaphysical science, an inspector of libraries, and at that time the secretary to the administration of public education, the conversation happily fell upon Theon of Smyrna's Astronomy. He told me that he had found its manuscript codex in the Royal Library and, having been distracted by other business...