FISH-NET PKESERVATIVES. 

 Table 4. — Water conditions at Key West, Fla. 



13 



MATERIALS TESTED. 



In this series 11 preservatives and preservative methods and a 

 control were tested. The preservatives and preservative methods 

 were copper oleate in four variations, B, C, D, and E; coal tar, F; 

 pine tar, G; the two tars in equal parts, H; quercitron and potassium 

 bichromate, I; petroleum product No. 1, J; proprietary water- 

 proofing material, K; and the Dutch method, L. 



The samples of No. 24 cotton line, six treated by each method, were 

 fastened to a frame made of galvanized iron pipe and immersed in a 

 cement tide pond at the U. S. Fisheries Station, Key West, Fla., on 

 November 7, 1921. A set of samples was removed every 3 weeks for 

 18 weeks. 



TENSILE STRENGTH. 



The samples were tested for tensile strength as already described 

 (p. 10) . Table 5 gives the results. These resmts are shown graphically 

 in Figures 3 and 4, but in Figure 4 those preservatives that give 

 similar results are grouped for easy comparison. In both figures the 

 curves are smoothed by the method of moving averages. 



Table 5. — Tensile strength of cotton lines exposed in sea water at Key West, Fla. 



Symbol and treatment. 



Unex- 

 posea. 



Number of weeks exposed. 



Tensile strength in pounds. 



A— White line, untreated control 



B— Copper oleate 7 per cent in gasoline 



C — Copper oleaio 7 per cent in gasoline, 5 per cent oil (by 



volume), 1-lOfKj cresol 



D — Copper oleate 11 percent in gasoline 



E— Copper oleate 11 per cent in gasoline, 2 per cent oil . . . 



F — Coal tar 50 per cent, benzol 50 per cent 



G— Pine tar 50 per cent, benzol 50 per cent 



H — Pine and coal tar, 25 per cent each, benzol 50 per cent. 



I— Quercitron and potassium bichromate 



J— Pet roleum product No. 1 



K— Proprietary waterproofing material 



L — Dutch method 



13.7 

 29.6 



34.5 

 37.9 

 35.4 

 44.4 

 41.0 

 51.0 

 14.4 

 17.0 

 16.2 

 24.4 



> Average of 60 breaks; every other figure in this table is the average of 15 breaks. 



