Every formed disposition of the soul realizes its full nature in relation to and dealing with that class of objects by which it is its nature to be corrupted or improved.
Salt water when it turns into vapour becomes sweet, and the vapour does not form salt water when it condenses again. This I know by experiment. The same thing is true in every case of the kind: wine and all fluids that evaporate and condense back into a liquid state become water. They all are water modified by a certain admixture, the nature of which determines their flavour.
Of means of persuading by speaking there are three species: some consist in the character of the speaker; others in the disposing the hearer a certain way; others in the thing itself which is said, by reason of its proving, or appearing to prove the point.
But the whole vital process of the earth takes place so gradually and in periods of time which are so immense compared with the length of our life, that these changes are not observed, and before their course can be recorded from beginning to end whole nations perish and are destroyed.