26 



U. S. BUREAU OF FISHERIES. 



is still not all that one could wish. It is an extremely severe test, 

 and no line that is seriously impaired in strength by exposure 

 endures more than a few strokes. Linen line will not endure more 

 than half a dozen strokes. The results it gives are influenced con- 

 siderably by tensile strength, though other factors also enter. Be- 

 cause of a rather wide variation 50 tests (five sets on the machine) 

 were made on each sample, and the figures here given are the averages, 

 respectively, of 50 tests. The lines were dry when tested. These 

 results, which are somewhat surprising, are shown in Table 9 and 

 graphically in Figures 14 and 15. 



360 

 340 

 320 

 300 

 280 

 260 

 240 

 220 

 200 

 180 

 160 

 1 140 



&; 



SI20 



oi 



^100 



rs 

 z 

 80 



60 



40 



?0 





as 



2 3 4 



NUMBER 0FM0NTH5 EXPOSED 



Fig. 14. — ^Wearing quality of cotton lines exposed in sea water at Beaufort, N. C. 



Among the points worthy of note are the following: Of the fresh 

 unexposed lines the untreated line, A, wore best of all. Any pre- 

 servative tried immediately diminished the wearing ability in the 

 following increasing order: The petroleum product No. 1, J, and 

 gilsonite, S, reduced the wearing quality least; the three tars, F, G, 

 and H, reduced it more; the copper oleates, M, N, O, and P (O show- 

 ing an apparently anomalous wearing quality), reduced it yet more; 

 and finally a group very low in wearing ability, consisting of all the 

 others, namely, the o»opper paints, Q and R, quercitron and potassium 

 biclu-omate, I, and the Dutch method, L, reduced it most of all. It 



