On this coarse of his studies on meteorology, he included that evaporated water exists in the air as an independent gas. He wondered how water and air could occupy the same space at the same time, when solid bodies can't. If the water and air were composed of discrete water particles then evaporation might be viewed as a mixing of water particles with air particles. He performed a mixture of experiments on mixtures of gases to determine what effects properties of the individual gases had on the properties of the mixture as a whole. While trying to explain the results of those experiments, he developed the hypothesis that the sizes of the particles making up different gases must be different.

Experiments