![Hexagonal electrode, for equipotential measurements](https://coimages.sciencemuseumgroup.org.uk/418/175/large_smg00052176.jpg)
Hexagonal electrode, for equipotential measurements
Hexagonal electrodes
Three hexagonal electrodes, c.1925, for equipotential measurements
Hexagonal electrodes
Hexagonal electrode, for equipotential measurements
Hexagonal electrode, for equipotential measurements