DEGRADATION. 187 



remains, first, that the water power, cceteris paribus, is a function of declivity ; 

 and, second, the" utilization of the water power, cceteris paribus, is a function 

 of declivity ; so that with a given amount of water and sufficient supply of 

 load, the rate of transportation through the agency of flotation depends on 

 declivity ; and the amount of transportation through driving also depends 

 on declivity. Therefore the rate of transportation of all mechanically com- 

 minuted matter is determined by declivity. 



I have spoken of the containing capacity of water for load of the same 

 or less specific gravity than water, but the amount of such load is so minute 

 in comparison with the whole amount that we may neglect it. Again, I 

 have spoken of the containing capacity of water for particles of load of 

 greater specific gravity than water; the amount of matter transported in 

 this way is great, but usually the supply is so limited that the containing 

 capacity is rarely reached ; but it seems probable from observations made 

 on transportation of bad-land detritus that there are times when this con- 

 taining capacity is actually reached, when the amount transported is limited 

 by this condition, that is, containing capacity. Then what is this contain- 

 ing capacity ? In matter of this character without water the rock power 

 cannot overcome interstitial friction, and hence the matter is not transported. 

 In order that it may be transported by rock power it is necessary, first, that 

 the interstitial spaces shall be filled with water; and, second, that an amount 

 of water be added sufficient to reduce interstitial friction so that it may be 

 overcome by rock power. And it is possible that this can be determined 

 mathematically for particles of any given form, size and weight ; but in 

 nature these forms are multifarious, and the determination of the containing 

 capacity is a proper subject of experiment. I know of no such experiments 

 having been made ; but, from observations in nature, I am led to the con- 

 clusion that the containing capacity of water for particles of this nature is 

 at least three times its own weight. 



Again I must remark that the last mentioned condition of transportation 

 is of very infrequent occurrence; and it remains, then, that in general trans- 

 portation, the rate is determined by declivity. 



Having now examined the processes of disintegration and transporta- 

 tion separately, we will examine them as combined in the 



