TY - BOOK AU - Gandon,Sébastien TI - Relations Theory According to Augustus De Morgan PY - 2009///. N1 - 77 N2 - This article aims at presenting Augustus De Morgan’s interpretation of the Euclidean theory of ratios. I show that De Morgan’s reading of the Elements, Book V, fits in the frame of his own mathematical practice. I also relate De Morgan’s interpretation to his new logic of relations UR - https://shs.cairn.info/journal-revue-d-histoire-des-sciences-2009-1-page-285?lang=en ER -