Iron rusts from disuse; stagnant water loses its purity and in cold weather becomes frozen; even so does inaction sap the vigor of the mind.-Leonardo da Vinci
Quella cavsa, che move li umori in tutte le spetie de’ corpi animati e che co quelle soccorre a ogni lesione, move l’ acqua dall’ infima profodita del mare alla soma altezza de’ moti, e come l’ acqua si leua dalle inferiori parti della vite all’alte tagliature.
The same cause which stirs the humours (body fluids) in every species of animal body and by which every injury is repaired, also moves the waters from the utmost depth of the sea to the greatest heights.
He is relating the blood pressure of living bodies and how when we bleed it forms clotting to the earth’s water cycle.
Gradissimi fiumi corrono sotto terra.
Very large rivers flow under ground.