Zinc for discovering pure metallic zinc, even though Swedish chemist Anton von Swab had distilled zinc from calamine four years previously. In his 1746 experiment, Marggraf heated a mixture of calamine and charcoal in a closed vessel without copper to obtain a metal. This procedure became commercially practical by 1752. William Champion's brother, John, patented a process in 1758 for calcining zinc sulfide into an oxide usable in the retort process. Prior to this, only calamine could be used to produce zinc. In 1798, Johann Christian Ruberg improved on the smelting process by building the first horizontal retort smelter. Jean-Jacques Daniel
Francis Metallic Surfboat Francis Metallic Surfboat The Francis Metallic Surfboat is a boat, currently housed at 130 West Center Street in Douglas, Michigan. It was listed on the National Register of Historic Places in 2015. It is one of two known surviving examples of its kind, one of the first type of coastal rescue craft used. The Francis Metallic Surfboat was designed by Joseph Francis, an inventor who specialized in inventing and constructing maritime lifesaving equipment. Francis constructed 137 of these vessels from about 1849 to 1857, of which 48 were used on the Great Lakes. This particular boat dates from approximately 1854,