Synopsis; In the study previously reported (Report No. 1), Model I was worked out for the investigation on moving to the outside the elements existing in a given area with the least resistance, on the assumption that the resistance is dependent solely upon the concentration of the elements and that the condition of various points on the ground surface is uniform.As a matter of fact, however, there are ups and downs on the ground surface and geological aspects are different in different places, which means that, as in the case of rivers, the form of ramified structure is varied and that an ideal one cannot be expected. Moreover, among tributaries there are very large ones such as the Kinu in relation to the Tone, of which the idea of trunk and branch lines in Model I will be of no use for explanation.This fact indicates that the idea of what are commonly called main and tributary courses of rivers does not always coincide with the idea of the trunk and branch lines in Model I. From the view-point of Model I, the relation between the Tone and the Kinu is not the one between the trunk and branch lines but running against each other of two rivers of nearly equal importance.Two streams runnig side by side and emptying into the same sea sometimes run far apart from, and sometimes draw close to, each other according to the ups and downs of the ground surface; they even run against each other. The collision results in a conflux, where ordinarily the, larger one is called the main course and the smaller the tributary course. Such phenomenas are very often experinced.For analysing these phenomenas, Model II was worked out on a principle which was quite different from that of Model I, and investigations were started chiefly by means of this new model.