Blowing into a wide mouthed bottle with a cork and two glass tubes.

Barometer demonstration

Blowing into a wide mouthed bottle with a cork and two glass tubes.

A mercurial barometer: "The cup or cistern of mercury is at A. By means of the screw C the mercury is forced up until the mercury surface in A is brought to the little pointer shown at B, which is the zero or beginning of the barometer scale. The height of the mercury in the tube is then read off from the scale at C. D is an attached thermometer." -Waldo, 1896

Mercurial Barometer

A mercurial barometer: "The cup or cistern of mercury is at A. By means of the screw C the mercury is…