National Geographic : 1919 Sep
Photograph from C.K.Edmunds LOWERING INTO PLACE THE LAST MATTRESS OF KAOLIANG STALKS AND SACKS OF CLAY WHICH FINALLY FORCED THE YELLOW RIVER BACK INTO ITS BANKS AFTER THE DEVASTATING FLOOD IN 1902 (SEEPRECEDING PAGE) Before being lowered into the gap, the last gigantic mattress was anchored to the side of the river by many 15-inch hawsers, inorder toprevent canting due to impact of the current. More than one hundred 8-inch ropes spaced closely were stretchedacross thebreach and made fast toanchor piles. On these were then placed alternate layers of kaoliang stalks and sacks of clay. When these materials reached thelevel ofthesides ofthe dam, the ropes were manned and, at a given signal, were lowered foot by foot. The kaoliang of whichthe mattress was made isakind ofsorghum, probably identical with Barbados millet. The core of the stalk, except for a very thin and weak covering, isentirely pith, butithasamatted bunch of fairly hard and strong roots which form its chief, virtue for construction work. The stalk is about6feet long, three-fourths ofaninch in diameter, and the bunch of roots, 3 to 5 inches in diameter. The face of the pakwerk. including the sides, iscomposed oftheroots which mat and make a splendid surface for keeping out water.