It will decrease this level and decrease the height. So there will be some discrepancy in the atmospheric pressure if there are molecules found within this section. So the more volatile the liquid that's used in this section, the higher the bigger pressure is. And that means the larger the difference from here to here, the lower this section will be. Now, the same way that you could measure the temperature of the atmosphere using a thermometer, you can also measure atmospheric pressure using a barometer. A barometer can be semblasing three things a long cylindrical tube open at one end and then select usually mercury and a cup.