^ 



:::: J-;j;::: JJ±|J: I !|^ | . | [ 1 1 1 [ ||j^ j||-||||ij-g : 

 :::::::-Sy i::[^44-|-T44ti- 4TH 1 1 1 1 1 1 1 ! " 



5,000 

 Revolutions of Barrel 



ROUNDING OF CUBES 



10,000 



o Rev. = I Mile) 



Fig. 27. — Showing convergence of diameters of cubes rounded by cobbles 

 averaging 70 grams each. 



