1386 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1954 



be arbitrarily defined as the number of operations at which 50 per cent 

 of the opens will have cleared. At this or any other value of / one obtains 

 from Fig. 7 fiFw^ = constant or il is inversely proportional to Fw . 



OTHER EFFECTS 



Fig. 9 shows the results obtained by varying other parameters. The 

 solid line, obtained from Fig. 7 is shown for comparison. Indicated are 

 the effects of fine polishing and rough polishing of the contact surfaces 

 and of increasing the mass of the moving contact from 0.5 to 4 grams. 



