| 词汇 | speculum-metal |
| 释义 | speculum metal noun[ U ] uk /ˈspek.jə.ləm ˌmet.əl/ us /ˈspek.jə.ləm ˌmet̬.əl/ a mixture of copper and tin that was used in the past to make mirrors: （旧时制镜用的）铜锡合金，镜青铜 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。 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. Chemistry: metals & metalworking anti-tarnish bar magnet base metal bimetallic brazen brazier bullion ferrous galvanized gilt gold leaf lode magnet silver plate tarnished tinplated untarnished vermeil wrought iron zirconium Examples of speculum metalspeculum metal Speculummetal was very hard to cast and shape. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. He chose an alloy (speculummetal) of tin and copper as the most suitable material for his objective mirror. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. For nearly 200 years speculummetal was the only mirror substance that could perform this task. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. After much experiment, he chose an alloy (speculummetal) of tin and copper as the most suitable material for his objective mirror. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. He started building his own reflecting telescopes and would spend up to 16 hours a day grinding and polishing the speculummetal primary mirrors. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Glass was also more thermally stable than speculummetal, allowing it to hold its shape better through temperature changes. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The poor optical quality of the early polished speculummetal mirrors meant that telescopic sights were not practical. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. All of these larger reflectors suffered from the poor reflectivity and fast tarnishing nature of their speculummetal mirrors. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. This saved on the severe light loss the image would suffer if he had used a speculummetal diagonal mirror. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Mirrors of speculummetal or any precious metal were hard to produce and were only owned by the wealthy. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The material their primary mirror was made of was speculummetal, a substance that only reflected up to 66 percent of the light that hit it and tarnished in months. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Since speculummetal mirror secondaries or diagonal mirrors greatly reduced the light that reached the eyepiece, several reflecting telescope designers tried to do away with them. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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