). ▁ ▁The ▁reflect or ▁wheel ▁was ▁not ▁plug able ▁and ▁had ▁remained ▁un changed ▁for ▁years ▁( and ▁because ▁of ▁( 5 ), ▁the ▁enemy ▁could ▁easily ▁establish ▁by ▁Hol ler ith ▁methods ▁for ▁example , ▁all ▁of ▁the ▁ ▁substitution ▁al ph ab ets ▁of ▁the ▁un pl ug ged ▁machines . ▁▁ ▁The ▁number ▁of ▁possible ▁wheel ▁combinations ▁was ▁only ▁ 6 0 , ▁since ▁the ▁set ▁of ▁whe els ▁belonging ▁to ▁the ▁machine , ▁at ▁least ▁in ▁the ▁case ▁of ▁the ▁Army ▁En igma , ▁only ▁consisted ▁of ▁ 5 ▁different ▁whe els . ▁ ▁F ault s ▁▁ 1 ▁to ▁ 4 ▁had ▁already ▁been ▁elimin ated ▁on ▁model ▁a ) ▁of ▁Schl üss el ger ät ▁ 3 9 , ▁ 5 . ▁then ▁no ▁longer ▁appears ▁vital . ▁On ▁the ▁other ▁hand , ▁however , ▁the ▁giving ▁up ▁of ▁the ▁adjust able ▁rings ▁and ▁of ▁the ▁ste cker ▁gave ▁rise ▁to ▁weak ness es ▁which ▁the ▁En igma ▁did ▁not ▁have . ▁In ▁fact , ▁the ▁absence ▁of ▁ste cker ▁S ▁cannot ▁be ▁compens ated ▁for ▁by ▁making ▁the ▁reflect or ▁wheel ▁U ▁pl ugg able ; ▁investig ations ▁into ▁En igma ▁had ▁shown ▁that ▁it ▁was ▁consider ably ▁more ▁difficult ▁to ▁find ▁out ▁the ▁ste ck ering ▁S ▁than ▁the ▁reflect oring ▁wheel ▁U . ▁ ▁In ▁detail , ▁the ▁results ▁of ▁the ▁investig ations ▁were ▁as ▁follows : ▁▁ ▁If ▁the ▁inner ▁w iring ▁and ▁the ▁clear ▁message ▁setting ▁of ▁whe els ▁I ,