Introductory Note

About five years ago I was engaged in preparing a catalogue of the ancient books which belong to Christ’s Hospital. One portion of these books consisted of a collection of ancient mathematical works presented at various times for the use of that part of the school which is known as the Royal Mathematical Foundation of King Charles II. Amongst them were some well known by name to every mathematical student, but which few have ever seen. Perhaps the most interesting of them all was a little volume, printed in London in 1653, containing Gassendi’s Explanation of the Ptolemaic and Copernican Systems of Astronomy, as well as that of Tycho Brahe, Galileo’s Sidereus Nuncius, and Kepler’s Dioptrics. I found Galileo’s account of his astronomical discoveries so interesting, both in matter and in style, that I translated it as a recreation from school-work. I venture to think that others also will be interested in following Galileo through the apprehension of his famous discoveries, and in reading the language in which he announced them.

About five years ago, I was preparing a catalogue of the old books belonging to Christ’s Hospital. Some were early mathematical works donated at various times for use by one part of the school. That part is known as the Royal Mathematical Foundation of King Charles II. Among these works were some whose names every mathematics student knows, but few have ever seen. Perhaps the most interesting of all was a small volume printed in London in 1653. It contained Gassendi’s Explanation of the Ptolemaic and Copernican Systems of Astronomy, along with his explanation of Tycho Brahe’s system. The volume also included Galileo’s Sidereus Nuncius and Kepler’s Dioptrics. I found Galileo’s account of his astronomical discoveries fascinating, both for its content and its style. So I translated the account as a break from schoolwork. I venture to think others will also enjoy following Galileo as he comes to understand his famous discoveries. They may also enjoy reading the words in which he announced them.