Unimaginable advances have been achieved in terms of increased life expectancy, reduced disease and access to lifestyles undreamed of by any tsar or pharaoh.
The activity of ions at the electrode surface changes when there is current flow, and there are additional overpotential and resistive loss terms which contribute to the measured potential.
They are tightly and economically composed and in terms of color, which he deploys judiciously, absolutely spot-on technique as far as nature is concerned.