52 



American Fisheries Society. 



It was therefore necessary to devise some means of measur- 

 ing the amount of abrasion or rubbing a line can stand. A motor 

 was arranged to draw samples back and forth over an edge, and 

 to count the number of strokes required to wear the line in two. 

 The great difficulty was in the nature of the edge. Woods of 

 various kinds were tried, but the results obtained thereby were 

 inconsistent because of lack of uniformity in the hardness of the 

 edge. Steel, hard rubber, glass, etc., were tried, but none of 

 these edges answered all the requirements of a satisfactory 

 standard. Finally, the threads were drawn across one another, 

 and the number of strokes necessary to wear out the sample was 

 taken as a measure of this factor. 



The construction and operation of the machine for making 

 this test is shown diagramatically in Fig. 7. A is an eccentric, 

 to which are fastened the lines to be tested, b and b^, which are 

 passed over the rollers, h and h^, fastened at c and c^. Other 

 pieces of the same line, d and d\ are made fast at e and e^, and 

 run through the slack part of b and b\ at f and f^ Weights of 1 

 kg. (g and g^) are attached to the free ends of the lower piece 

 of line. The eccentric A is revolved by a motor, imparting a 

 reciprocating motion to the samples b and b^, and causing them 

 to saw across similar sample, d and d^ The samples thus wear 

 out and the weights drop to the floor; the number of strokes 

 necessary to wear each sample down to a breaking strength of 



h 



/^ 



L\(J 



Fig. 7. — Apparatus used for testing the wearing quality of lines. 



1 kg. is taken as a measure of the wearing quality. The machine 

 was made so as to run 10 samples at a time, and a mechanical 

 revolution counter was used to assist in keeping count. 



Table V herewith gives the results of the mechanical wear- 

 ing tests on the various samples exposed and tested. 



