I- 

 z 



UJ 



o 

 q: 



UJ 



a. 



100 



- <D-: AO'O. 



50 



O-O-o 



J I I L 



J I 1- 



450- 



350 



ac 



250 



150- 



50 



Figure 13. — Effects of crude oil mixed with carbonized sand on the 

 percentage of time oysters remain open and on the total volume of 

 water pumped. Oyster No, 3, experimental; and oyster No. 4, control. 

 The control is indicated by open circles. Rubber apron method. 

 July 17 to August 18, 1948. 



