HOW TO PROVE BY EXPERIMENT THAT AIR HAS WEIGHT
The air-globe is a piece of apparatus for demonstrating that air has weight. (See Fig. [3].) First, the air-globe is weighed and then the air is pumped into it; its stop-cock is closed and the globe is reweighed. It will be found to have gained in weight. This is conclusive that air is matter and that it has weight.
Fig. 3
Fig. 4
Of great importance to us in the study is the next fact, that air exerts pressure on everything about us and upon ourselves.