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BELL SYSTEM TECHNICAL JOURNAL 



fers to transmission from west to east and the second line from east to 

 west. The hangovers are those of the relays which short the indicated 

 transmission path , for example, the figure 0. 1 86 in the first line of Table 

 I refers to the hangover of the relay at the west end of the circuit which 

 shorts the transmission path from west to east. The designation in 

 Table I indicates the grouping of conditions for observation. All con- 

 ditions having the same numeral in the designation were observed con- 

 currently, the procedure being to observe 25 calls on condition a, then 

 25 calls on condition b and so on. In this way seasonal variations and 

 uncontrolled effects at the terminals or in the transmission line have been 

 minimized for a group of conditions bearing the same numerical desig- 



TABLE I 



