----------------- HES POSTING ----------------- Tom Walker suggests that "the origin of supply and demand curves has to be somewhere in medieval heraldry -- some kind of graphic representation of crossed swords..." I am not very sure about heraldry, but search in medieval sources might be fruitful. One example is Oresme's graphic interpretation of Aristotelian justice in exchange. Regards, Yuri Tulupenko ------------ FOOTER TO HES POSTING ------------ For information, send the message "info HES" to [log in to unmask]