Thermodynamics lab tech was pretty advanced by that time. The part that reads bogus to me is the fractions of a mm, water meniscus is sensitive to contaminatio

Thermodynamics lab tech was pretty advanced by that time. The part that reads bogus to me is the fractions of a mm, water meniscus is sensitive to contamination and diameter, its "always" been easier to measure liquid masses to higher sig figs than to measure liquid volumes, I suspect the journalist filter turned mg into mm or the precision scale produced repeatable results equivalent to fractions of a mm in the container. The only solution I can come up with that would work in that era would be something weirdly optical involving mirrors and multiple floats. I vaguely remember a quarter century ago in a chemistry lab placing a beaker of distilled room temp water in a very nice precision scale as a demonstration while the instructor had us calculate how long it would take the inch or so of water to evaporate based on the slowly decreasing mass, and the result during a dry winter was somewhere around a month. The room must have been sealed and 100% humidity because small fractions of a mm in height would represent in a very hand wavy way around a minute of evaporation if represented as time in normal winter lab air. I also wonder how volume of water changes as CO2 is absorbed or emitted by the water, even the smallest gas bubble could mess up fraction of a mm measurements.