A difference in alkali metal vapor pressure on the opposite sides of electrolyte tube 14 results in the creation of {HEAD ~ a difference} in {TAIL ~ electrical potential} across the electrolyte 
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A difference in alkali metal vapor pressure on the opposite sides of electrolyte tube 14 results in the creation of { HEAD ~ a difference } in { TAIL ~ electrical potential } across the electrolyte
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH