How did Georg do it?

An article by L A  Geddes and L.E.  Geddes, explains how Georg Ohm discovered the  Ohm’s law. As the authors tell, Georg Ohm  lived  at a time when  there were no calibrated indicators for electric current:  no volt or amp, because these were established much later.  The resources available  to Ohm were:  1) the discovery of Oersted, who in 1820 showed that a magnetic field surrounded a wire carrying electric current; 2) the electrochemical cell, described by Volta in 1800; and 3) the thermoelectric effect, discovered by Seebeck in 1822. In fact, the Seebeck effect is giving a quite stable source of current.
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