The concept of metal bridges may have come to Europe from China. In the seventeenth century Kircher saw and described a Chinese bridge which seems to have been a genuine suspension bridge of metal, a true forerunner of the Pont de la Caille, over the Pass of Usses, and of the immense Pont de Beaucaire, which in four spans unites Beaucaire to Tarascon, covering a distance of more than 438 metres.[140] Who can explain why backward China has hit upon many fertile ideas before the more enterprising nations? Why has she not learnt to rule the world? Perhaps her body has been too numerous for her brain. On my table lies the photograph of a bridge which may be similar to the one admired by Athanase Kircher. It is an iron swing bridge in Western China, near Auhsien. There are three piers, two of stone, and the other a makeshift of two timber piles joined together at top by a log upon which the footway rests. The carpentry of the footway is primitive: across the long bearing beams, which are not at all thick or heavy, a great many slim laths lie unevenly; and up the middle of the bridge, from end to end, is a narrow path made with long and flat planks which rest upon the transverse timbering. As for the iron suspension, it is a chain of thick and short rods which are linked firmly together. These rods, thus looped at each end and interlocked, run in two lines from abutment to abutment, making a sort of parapet at each side of the bridge. Bamboo rods suspend the footway to the iron chains, which pass over the abutments to be fastened securely on the ground.