An alloy of tin and copper used for telescope mirrors until the mid-nineteenth century, when it was replaced by silvered glass mirrors. Its reflectivity is only approximately 66%, and must be repolished when it tarnishes.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。