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Galvanism

Galvanism.  The branch of physical science dealing with electrical currents. It is named after Luigi (or Aloisio) Galvani (1737-1798), an Italian who is credited with its first observation (1791). Shortly after Galvani's discovery it was another Italian, Alessandro Volta (1745-1827) who developed the voltaic pile (1800) that lead to the primitive battery which supplied the current necessary for electrolysis.  

The application of galvanism to coins and medals is in electroforming and

electroplating. Pattern making is possible by electrogalvanism in such fidelity that oversize patterns can be used on the die-engraving pantograph to cut dies and hubs in fine detail for coins and medals. The term for these electroformed patterns is called galvano, a term named directly after Luigi Galvani.

Galvanism was set back with the rise of "electrotherapeutics" – the use of small electric currents in treatment of human ails. A galvanic cell was placed next to the skin of an affected person. An example was the Boyd's Battery Medal illustrated. It was of no benefit or healing whatsoever, but even the Encyclopedia Britiannica treated the subject with great reverence even into the 20th century.

 

Galvanos are metal shells which replicate a bas-relief design. They are made in an electrolytic tank usually of pure copper but can be any metal which conducts electricity. They are ideal to serve in the negative as the patterns for dies, from oversize to cut a die in any size. Galvanos were an important step for the production of all coins and art medals by all mints in the last half of the 20th century, being gradually replaced by epoxy molds by 2010. They also make spectacular wall plaques in positive form. Note the wide flange on the edge outside the design, this is where clamps hold the galvano in position while it rotates.  Photo: Medallic Art Co. 

excerpted with permission from

An Encyclopedia of Coin and Medal Technology

For Artists, Makers, Collectors and Curators

COMPILED AND WRITTEN BY D. WAYNE JOHNSON

Roger W. Burdette, Editor


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