Talk:Euclid's Optics

Error in text?

In the Latin text of Heiberg's edition the proof of the proposition on page 65 seems to have got garbled or misprinted. The theorem itself is valid but I can't see any way of getting it from the text as printed. (I don't read Greek at all, so I'm not sure about the Greek version.) The English translation of this point is also garbled. Incidentally, the diagrams as printed in Heiberg's edition are clearer than those in the English translation, so Heiberg may be useful even to non Greek and Latin readers.[Added by the same author:

I am fairly sure that the error is in the Latin version.  Even without knowing Greek, but recognizing Greek delta as D and gamma as G, it is evident that the lettering of lines and angles in the Latin version diverges from the Greek version. The Greek version has 23 terms (AZ, DAZ, etc) while the Latin has only 19, and even where the terms appear to correspond, there are discrepancies between them, e.g. the Greek has AZB where the Latin has AZD.  As far as I can see, the Greek version supports a valid proof while the Latin doesn't. 2A00:23C8:7907:4B01:4D11:5AC8:9AE3:D6EE (talk) 19:36, 2 November 2023 (UTC)