In Scheele's Chemical Treatise on Air and Fire he states: "air is composed of two fluids, differing from each other, the one of which does not manifest in the least the property of attracting phlogiston, whilst the other, which composes between the third and fourth part of the whole mass of the air, is peculiarly disposed to such attraction."
In Scheele's treatise on air and fire, he describes air as consisting of two distinct components: one that does not attract phlogiston, while the other, which makes up roughly a third of the air, is strongly attracted to it.