Comparing the correlation length of grain markets in China and France

In economics, comparative analysis plays the same role as experimental rese arch in physics. In this paper, we closely examine several methodological p roblems related to comparative analysis by investigating the specific examp le of grain markets in China and France respectively. This enables us to an swer a question in economic history which has so far remained pending, name ly whether or not market integration progressed in the 18th century. In eco nomics as in physics, before any new result being accepted, it has to be ch ecked and re-checked by different researchers. This is what we call the rep lication and comparison procedures. We show how these procedures should (an d can) be implemented.