1 899 



THE PRESIDKNT'S ADDRESS 



17 



In this case, as in many others whereof we have 

 cxamj)lcs at home, the real bed of the stream is many feet 

 below the channel of the flowing water. In Coffee Creek 

 the valley has been filled up with several feet of gravel. 

 The annexed diagram, which represents a cross-section of 

 the stream, its gravel deposits, and its original valley, will 

 explain my meaning. 



Fig. I. — Cross section of a stream and its valley. 



In this diagram a, a, a mark the solid rock called " Bed- 

 rock ; " b, b, b are beds of gravel which may be of very 

 great thickness ; c, c indicate the actual channel of water. 



Consequently the bed of gravel or sand below the 

 running stream is saturated with water, and the bulk of 

 any gold gravitates to the bottom of the mass of gravel to 

 become lodged in the crevices of the bed-rock. It is 

 almost certain that the whole body of gravel glides slowly, 

 very slowly, down stream with a movement similar to that 

 of a glacier, and, as it moves, all the particles of gold it 

 contains will tend downward in the mass. 



Since the gravel is permeated with water, directly a 

 hole is made in it by boring, drifting, or open-cut, it is 

 immediately filled with water, and endless are the con- 

 trivances invented by man's ingenuity to enable him to 

 get rid of the w'ater and follow down the bed-rock. But 

 in a stream of the volume of Coffee Creek all contrivances 



B 



