Sentence:  Several germanium resistors have been thermally cycled from 300 to 4.2 * * f and their resistances have been found to be reproducible within 1 3 millidegree when temperatures were derived from a vapor pressure thermometer whose tubing is jacketed through most of the <WSD>liquid</WSD> helium . 
Meaning of the word marked with <WSD> tags:  existing as or having characteristics of a liquid; especially tending to flow