Group 12 element people in the 17th century. German chemist Andreas Marggraf is usually given credit for discovering pure metallic zinc in a 1746 experiment by heating a mixture of calamine and charcoal in a closed vessel without copper to obtain a metal. Experiments on frogs by the Italian doctor Luigi Galvani in 1780 with brass paved the way for the discovery of electrical batteries, galvanization and cathodic protection. In 1880, Galvani's friend, Alessandro Volta, invented the Voltaic pile. The biological importance of zinc was not discovered until 1940 when carbonic anhydrase, an enzyme that scrubs carbon dioxide from blood, was shown to
Ore condition right order in "D" includes the condition that "D" must consist entirely of elements of the form "rs". Any domain satisfying one of the Ore conditions can be considered a subring of a division ring, however this does not automatically mean "R" is a left order in "D", since it is possible "D" has an element which is not of the form "s""r". Thus it is possible for "R" to be a right-not-left Ore domain. Intuitively, the condition that all elements of "D" be of the form "rs" says that "R" is a "big" "R"-submodule of "D". In fact the