Modified
from Nebergall et. al 1976

Note that when water vapor pressure equals atmospheric pressure, then the
water molecules are free to jump into the gas state. The pressure "up"
cancels the pressure "down" and boiling begins.

To find a value not on the chart you must *interpolate*. This can
introduce some error since water vapor pressure in not a straight line graph.

Example: Set up a proportionality and solve for X. Use the chart entry
closest to the number you want. 32C is closer to 30 than to 35 so

____30C
__ = ____35C
__

**31.8mm
Hg
X **

**X = 37.1 mm Hg**