BAMBOO — McCLURE 399 



siderably greater tensile strength per unit of weight than the twisted 

 sort. For tracking purposes (towing river boats by manpower), the 

 superiority of the braided rope is outstanding. Being of open con- 

 struction and consisting of coarse units, it holds less water and dries 

 more quickly after having been submerged. Again, in places where 

 the towpath swings around the convex side of a rock cliff, the rope 

 often rubs against the rough surface under considerable tension. When 

 the plaited type of rope becomes damaged by this hard usage, individ- 

 ual strips may be replaced, thus restoring it more or less completely 

 to its original condition. When this rope becomes so aged or worn 

 that it must be discarded, it is cut into convenient lengths, dried, and 

 used for torches. 



Small bamboo ropes of the twisted type are commonly employed for 

 such temporary functions as binding together the units of rafts made 

 up of lumber, fuel wood, or bundles of bamboo, for transportation by 

 water. When these rafts are moved by means of the stream current or 

 the tide instead of being towed, guiding, braking, and anchorage are 

 miraculously accomplished by means of stone-weighted wooden an- 

 chors attached to the stern by means of bamboo rope, and floated inter- 

 mittently upon smaller, trailing bamboo pilot rafts. The passage 

 boats operated on the inland watercourses are towed by means of large 

 twisted bamboo ropes or cables. Bamboo ropes are used in western 

 China for drilling salt wells and for hoisting brine. 



BAMBOO AS A BUILDING MATERIAL 



In vast areas, bamboo is the one material that is sufficiently cheap 

 and plentiful to fill the tremendous need for economical housing (pi. 3, 

 fig. 1). Bamboo is employed in many ways, often as much for its 

 ornamental value as for its superior fitness in homes built primarily 

 of more substantial and more costly materials. It is eminently suited 

 and economically desirable for the construction of all parts of a house. 

 It serves admirably for the builder's scaffolding as well. The natural 

 units, or culms, are of a size and shape that make handling, storing, 

 and processing both convenient and inexpensive. The characteristic 

 physical structure of the culms gives them a high strength-weight 

 ratio. They are round or nearly so in cross section and usually hollow, 

 with rigid crosswalls strategically placed to prevent collapse on bend- 

 ing. The strong, hard tissues of great tensile strength are most highly 

 concentrated near the surface of the culm walls. In this position they 

 can function most effectively, both in giving mechanical strength and 

 in forming a firm resistant shell. Because of the nature of their sub- 

 stance and grain, bamboo culms are easily divided by hand into shorter 

 pieces by sawing or chopping, or into narrow strips by splitting. No 

 costly machines are required; simple tools suffice (pi. 4, fig. 1). The 



