PREFACE.

They This refers to previous editors mentioned on the preceding page, specifically those who followed Peyrard's work. acted in such a way that the text of the Elements Euclid's primary work on geometry and number theory. might seem to rest on a fairly certain and ready-to-use foundation. It is well known that the situation with Euclid's other writings was even worse.

Since I saw that many people understood these things, I decided to add Euclid to my work on Archimedes J.L. Heiberg published a significant edition of Archimedes' works just before this Euclid project.. I had thought about this task for a long time. I was encouraged to finally start because my edition of Archimedes was received kindly by scholars. They forgave the errors I could not avoid in those early efforts. I hoped that my experience would allow me to produce better work now.

But it soon became clear that my resources and strength were not enough for the whole project. Many manuscripts original: "codices" needed to be compared. Many distant libraries had to be visited. I asked Heinrich Menge 1841 to 1913, a German classical philologist and educator., a learned man who was also working on Euclid, if he would take part of the work. He agreed. We arranged that he would edit the Data, Phaenomena, and the musical writings. I would edit the Elements, Optics, and Catoptrics. We would work together to compare the manuscripts.

Even then, I had to choose only a few sources from a massive amount of material for the Elements. Almost every library, even the smallest ones, keeps some manuscript of the Elements. It was impossible to compare or even look at every one. I wish I could have used more. However, the special way these texts were preserved makes the few manuscripts I used sufficient. These manuscripts are very old and of high quality. It is well known...