I have set a cup of water in a bell jar, with a thermometer. I am able to lower the pressure until the water boils and I am able to measure the temperature of the water simultaneously. I then looked at a phase diagram for water, and found where the temperature axis line intersects the liquid to vapor phase change line. I then used the Antoine Equation to solve for the pressure at which the water was observed to start boiling.
I have several electronic barometers (which measure in inches of water column) and are showing several inches difference between then. I am looking for a good way to set them to a known absolute pressure reference.
Is this a good way to determine barometric pressure? Is it prone to a bunch of esoteric sources of errors? Is there a method available that I can follow to do this experiment with uncertainties?