Introductory; 1. The Woepcke-Euclid MS.; 10-13. Summary; 18. Abraham Savasorda, Jordanus Nemorarius, Luca Paciuolo; 19. Connection between Euclid's book On Divisions, Apollonius's treatise On Cutting off a Space and a pappus-lemma to Euclid's book of Porisms; 22-57.