One of the things I cannot account for is the persistence of the "psi"..."pounds per square inch". What the f... is that? And there is also an issue with "psi", and "psig"; the latter is "pounds per square inch gauge", and the ZERO reading on this scale is 1*atm or "32 psi"...And so a reading of 1-2*"psig" is a bit over one atmosphere.
I think these days the preferred pressure measurement is "1 bar", where "1 bar" is almost an atmosphere... Chemists traditionally used the "atmosphere", an accessible and meaningful unit...especially so as a mercury manometer could be set up to measure pressure AT or below "1 atmosphere..."
And 1*atm-=760*mm*Hg... Of course, these days the mercury manometer and the McLeod gauge have all but disappeared from modern laboratories. At least we won't die now!
