Further along we came upon the scene in Fig. 103 where the building of the stack of compost and the gathering of the mud from the canal were simultaneous. On one side of the canal the son, using a clam-shell form of dipper made of basket-work, which could be opened and shut with a pair of bamboo handles, had nearly filled the middle section of his boat with the thin ooze, while on the other side, against the stack which was building, the mother was emptying a similar boat, using a large dipper, also provided with a bamboo handle. The man on the stack is a good scale for judging its size. We came next upon a finished stack on the bank of another canal, shown in Fig. 104, where our umbrella was set to serve as a scale. This stack measured ten by ten feet on the ground, was six feet high and must have contained more than twenty tons of the green compost. At the same place, two other stacks had been started, each about fourteen by fourteen feet, and foundations were laid for six others, nine in all. During twenty or more days this green nitrogenous organic matter is permitted to lie fermenting in contact with the fine soil particles of the ooze with which it had been charged. This is a remarkable practice in that it is a very old, intensive application of an important fundamental principle only recently understood and added to the science of agriculture, namely, the power of organic matter, decaying rapidly in contact with soil, to liberate from it soluble plant food; and so it would be a great mistake to say that these laborious practices are the result of ignorance, of a lack of capacity for accurate thinking or of power to grasp and utilize. If the agricultural lands of the United States are ever called upon to feed even 1200 millions of people, a number proportionately less than one-half that being fed in Japan today, very different practices from those we are now following will have been adopted. We can believe they will require less human bodily effort and be more efficient. But the knowledge which can make them so is not yet in the possession of our farmers, much less the conviction that plant feeding and more persistent and better directed soil management are necessary to such yields as will then be required.