Un moulin chinois du XIIe siècle

Abstract

The mill presented in this article appears in a 12th century wall painting preserved in a Buddhist temple located at the foot of Wutai shan, in Northern China. As a whole, this piece belongs to the landscape painting tradition of the Song dynasty. Several of the scenes adjacent to this one illustrate the legend of Hariti, the child-eating ogress converted by the Buddha Sakyamuni. It is difficult, however, to establish a connection between this famous legend and the mill theme. This mill is very interesting in the history of techniques. It is one of the oldest paintings of a Chinese hydraulic facility that had survived to the present day. This painting is also older than all the pictures of hydraulic machines appearing in known technical and agronomic treatises. Finally, it uses a technology that is fairly complex for that time: the mill is equipped with a vertical driving wheel which actuates a dual mechanism consisting of a grinding mill and several trip-hammers. The painting, which seems to have been based on an original piece of equipment, shows the various mechanisms with extreme realism, care, and accuracy, thus allowing a detailed technical study. A comparison is necessary with the machines studied and shown in books printed at a later date, more specifically with those of Wang Zhen's Agricultural Treatise (Nongshu, 1313), since this book contains the machines that were copied over and over by all the treatises and encyclopedias until the 18th century. This comparison not only concerns the mechanical aspects, but it also applies to the evolution of the illustration style over the centuries. Apparently, this evolution is not toward greater technical accuracy. Finally, the article recalls the evolution of pounding and grinding processes in the history of techniques. It focuses on the linkage between the needs and the social and dietary customs on the one hand, and technical processes on the other. This linkage explains the differences between China and the West with respect to the chronological order of inventions and the relative importance of each of the grain processing techniques.