Earths were defined by theAncient Greeks as "materials that could not be changed further by the sources of heat then available".[1] Severaloxides were thought to be earths, such asaluminum oxide andmagnesium oxide.[1] It was not discovered until 1808 that these weren't elements but metallic oxides.[1][2]
By the early 1800s it became clear that the earths, formerly considered to be elements, were oxides, compounds of a metal and oxygen.
 | Thishistory of chemistry article is astub. You can help Wikipedia byexpanding it. |