Which is more accurate: mercurial or aneroid sphygs?
By law, both instruments must initially be within 3mmHg of a reference standard. However, because aneroid gauges rely on gears and mechanical linkages, mercury instruments will likely REMAIN accurate for a longer period of time. However, there is a tradeoff. Mercury instruments are generally not as portable and necessitate the use of 999.9 pure elemental mercury which is being outlawed by more and more municipalities and states.
