Taylor and Wells. — Preservation of Nets and Lines. 49 



Table IV. — Tensile strength in pounds of No. 24 cotton lines put down 



IN THE SEA AT BeAUFORT, N. C, FEBRUARY 15, 1922. 



[One of each taken up each 80 days over a period of 6 months. Each fl^ure 

 is an average of 15 breaks except the untreated and unexposed control, 

 which is an average of 60 breaks.] 



Sym- 

 bol 



Treatment 



Tensile strength, in pounds 



Not 

 ex- 

 posed 



Exposed, months 



A 

 F 

 G 

 H 



I 

 J 



M 



N 







tar, 



White line 



Coal tar , 



Pine tar 



Coal and pine 



equal parts 



Bull's method 



Petroleum Product, 



No. 1 



Copper oleate 7.5%; 



8 mg. copper per 



yard 



Copper oleate 7.5%; 



12 mg. copper per 



yard; 5% oil; 1- 



1,000 cresol 



Copper oleate 12.5% 



solution; 18 mg. 



copper per yard . . . 

 Copper oleate 18 mg. 



copper per yard; 2% 



oil 



Copper paint I; 50% 



creosote oil 



Copper paint II 



Gilsonite 



Petroleum Product, 



No. 2 



Dutch method 



39.3 

 35.4 

 35.2 



37.4 

 39.3 



39.0 



34.2 



33.2 



33.6 



36.3 



41.5 

 41.7 



35.5 



32.9 

 38.6 



33.0 

 46.0 

 45.0 



45.0 

 42.4 



40.0 



36.2 



35.2 



36.6 



37.2 



42.0 

 48.0 

 28.2 



34.0 

 40.3 



5.3 



44.9 



46.9 



46.8 

 19.6 



23.4 

 36.6 



33.8 

 40.3 



39.0 



42.4 

 50.0 

 14.5 



5.7 

 37.0 



2.9 



36.2 



33.8 



33.9 

 3.2 



8.7 

 28.6 



33.9 

 30.0 



37.0 



40.8 



49.5 



8.5 



X 



35.3 



X 



23.2 

 11.9 



27.9 



X 



16.6 



25.4 



21.3 



29.7 



41.0 



47.0 



3.9 



X 



20.3 



X 



18.0 

 3.1 



16.2 



X 



11.0 



20.8 



25.1 



19.5 



33.0 

 40.0 



X 

 X 



8.3 



X Indicates that the line is disintegrated. 



DISCUSSION OF tensile; strength in the ught of the foregoing 



EXPERIMENTS. 



Tensile strength is oiie of the most important properties of 

 the lines used for fishing gear, and has been the only factor 

 measured by other investigators. In considering the changes in 

 tensile strength as influenced by preservation, it is necessary to 

 consider (1) immediate increase or decrease of strength of line, 

 caused by the physical properties of the preservative; (2) a 

 later change in the tensile strength, caused by drying or other 



