Tower Windmills in Medieval England: A Case of Arrested Development?

摘要

Harnessing wind power, one of the great technological achievements of the Middle Ages, was a phenomenon of some historical complexity. The origins of the wind-power concept and the timing of its practical application around the Middle East and Europe are not clear. In one region (the area around the lower North Sea), the crucial period of invention or innovation appears to have been the late twelfth century. Here, structures called "windmills" (that is, molendina ventritica or molendina ad ventum in Latin) were recorded in northwestern European documents from the 1180s on. These mills mounted sails in the vertical plane and directed their turning force through a horizontal axis to drive the machinery within; credit for their initial appearance has been claimed for a number of areas around the North Sea littoral and even the Rhine valley. Over time, however, distinc tive variations in windmill design became evident in the lower North Sea region. It is the purpose of this study, by using linguistic, iconographic, and (occasionally) archaeological evidence from medieval England, to focus upon one of these variations—the tower windmill (usually shortened to "tower mill" in the literature)—in order to illuminate some of the complexities involved in the dissemination of wind power at the time. In particular, we wish to survey and enhance current knowledge about the spread of tower mills in medieval England, and to examine why it was so anemic— the "arrested development" in the subtitle. We feel that the limited diffusion of tower mills might tell us much about how wind power was promoted, and by extension its technical development, in medieval times. Specifically, we mean to suggest—which is not the same as thoroughly demonstrating—that there were particular interests associated with carpenters holding back the dissemination of tower windmills.