John Frederic Daniell (1790-1845) invented the constant battery in 1836. He meant it to be a philosophical instrument to be utilized in both lecture demonstrations and electrochemical laboratory research. But the constant battery was taken up in electrometallurgy, not primarily as a source of electric current but more as an electrodeposition device. As such it became an essential tool in the development of galvanoplastics (electroforming). This article traces the tortuous transformation of this lecture demonstration apparatus into an electrometallurgical tool, and includes some aspects of British and French patent laws, and the electrogilding industry.