speculum metal
noun [ U ] uk/ˈspek.jə.ləm ˌmet.əl/ us/ˈspek.jə.ləm ˌmet̬.əl/
（旧时制镜用的）铜锡合金，镜青铜
a mixture of copper and tin that was used in the past to make mirrors
Mirrors made of speculum metal may have also been produced in China and India. 中国和印度可能也生产过用镜青铜做成的镜子。
- More examples
- Mirrors of speculum metal were hard to produce and were only owned by the wealthy.
- Speculum metal is an alloy of around two-thirds copper and one-third tin.
- A small portion of speculum metal, when analysed, yielded iron.
- Speculum metal and brass cannot be soldered together by the ordinary methods.