  The kinetic theory was able to explain the gas laws connecting volume, temperature and pressure. It also predicted Avogadro’s law that equal volumes of gases contain equal numbers of molecules and so explained Gay Lussac's law also. This legitimated the use of vapour densities for the determination of relative molecular weights.  This in turn led to definitive atomic weights and formulae that coincided with those that organic chemistry had yielded by the 1860’s. The kinetic theory of gases also explained the laws of diffusion and even predicted a novel phenomena that was quite counter-intuitive, namely, that the viscosity of a gas, the property that determines its ease of flow and the ease with which objects flow through it, is independent of its density. Counter-intuitive or not, the prediction was confirmed by experiment.