FISH-NET PRESERVATIVES. 



17 



No. 1, J; and also a similar material by new formula by the same 

 company, wliicli we designate petroleum product No. 2, symbolized 

 by X; tile Dutch method, L; foiu* variations of copper oleate, M, N, 

 O, and P; two commercial brands of copper paint sold for fish-net 

 preservatives. No. 1, Q and No. 2, R. 



TENSILE STRENGTH. 



Of the preservatives here considered for the first time the two 

 samples of copper paint cause an immediate increase in the strength 

 of the line. These materials, containing cuprous oxide, suspended 

 in a binding material, cause great internal friction, which manifests 

 itself in its effect on tensile strength and also, as wall be seen later, 

 on flexibility and the mechanical wearing quality of the lines. All 

 of the other materials caused the usual diminution of tensile strength 

 by internal lubrication. 



The results of tensile strength measurements are given in Table 7. 

 The same results are shown graphically in Figure 5, where the 

 individual preservatives are shown, and in Figiu-e 6, where the 

 preservatives that behave similarly are presented in groups, such 

 groups being the copper paints, copper oleates, and tars. 



Table 7. — Tensile strength of cotton lines exposed in sen water at Beaufort, N. C. 



Symbol and treatment. 



A— White line, untreated control 



F — Coal tar 50 percent, benzol 50 per cent 



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



H — Coal and pine tar, 25 per cent each, benzol 50 per cent.. 



I — Quercitron and potassium bichromate 



J — Petroleum product No.l 



L — Dutch method 



M— Copper oleate 7.5 per cent in gasoline 



N — Copper oleate 7.5 per cent in gasoline, 5 per cent oil, 



1-1000 cresol 



O — Copper oleate 12.5 per cent in gasoline 



P— Copper oleate 12 J per cent in gasoline, 2 per cent oil 



Q — Copper paint No. 1, 50 per cent creosote oil 



R — Copper pauit No. 2 



S — GiLsonite 



X — Petroleum product No. 2 



Unex- 

 posed 



139.3 

 35.4 

 35.2 

 37.4 

 39.3 

 39.0 

 38.6 

 34.2 



33.2 

 33.6 

 36.3 

 41.5 

 42.7 

 35.5 

 32.9 



Number of months exposed. 



Tensile strength in pounds. 



(2) 

 (') 

 (') 

 (») 

 (') 

 (») 



4.9 



9.7 



12.0 

 8.8 

 16.9 

 18.9 

 38.3 

 (») 



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

 3 Sample was disintegrated and gone. 



Upon exposure the lines Q and R, preserved with copper paint, 

 are easily in the lead, as far as preservation of tensile strength is 

 concerned. At the end of six months' exposure lines preserved by 

 them are nearly as strong as the original imtreated line, though a 

 weakening begins to appear in three or four months. Next to 

 those preserved with copper paint, in the diminishing order of tensile 

 strength at the end of six montlis' exposure, come those treated 

 with the copper oleates, the Dutch method, and the tars. Of these 

 the tarred lines, F, G, and H, made an excellent showing for two 

 months (that is, as long as creosote was present), after which a very 

 rapid deterioration occurred. The establishment on them of a 



