416 



U. S. BUREAU OF FISHERIES 



I Z 3 4 5 



NUMBER Of MONTHS EXPOSED 



Fig. 2. — Tensile strength of cotton lines immersed continuously at Boothbay Harbor, Me. 



50 



45 



40 

 */> 



a 



o 

 z 30 



X 



t; 25 



z 



ui 



t^ 20 



^'5 



Fig, 



12 3 4 5 6 



NUMBER OF MONTHS EXPOSED 



3. — Tensile strength of cotton lines immersed intermittently at Boothbay Harbor, Me. 



