surface only. It was, of course, abandoned with the development of electroplating and the ability to reverse plate (switch the current flow, the object becomes the anode where the molecules of gold are drawn off the object to deposit on the cathode). See electroplating.
excerpted with permission from
For Artists, Makers, Collectors and Curators
COMPILED AND WRITTEN BY D. WAYNE JOHNSON
Roger W. Burdette, Editor