T(s) 



Figure 10. Distribution of N and T for experiments 58 to 84 with the 

 0.18-millimeter sand. Asterisks denote experiments with 

 the bed initially leveled. Symbols are defined in Table 1. 

 Arrows point downward to observations of Tj. and upward to 

 supplementary observations of T . (a = 0.4576 N centimeters.) 



36 



