1398 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1953 



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Fig. 4 — Dynamics of mercury contact, (a) Armature against contact on right. 

 Note spherical shape of mercury on left contact, (b) Armature moves to left, 

 drawing out mercury bridge, (c) Armature further to left; bridge about to break, 

 (d) Armature reaches contact on left. Mercury bridge has broken in two places, 

 leaving a tiny ball which later drops away. 



