Abstract: Apparatus for measuring weight, level and or volume of a volatile liquid in a sealed container, comprising: a housing, capable of sustaining high pressure; a load cell, located within the pressure housing, mounted on an external pipe flange at the top of a sealed container having known cross section and containing a liquid of a known specific gravity; a displacer weight of known weight and length passing through the pipe flange opening and suspended above the bottom of the container. The apparatus, operating on the inferential method of determining liquid quantity by weight in a sealed vessel, works on the principle that when there is no liquid in the tank, the load-cell and its meter system sense the maximum weight of a displacer cylinder which is the null or "Zero" point for measurement. The buoyancy of the displacer weight in the liquid then reflects the volume in the container via a meter/computer display.