speculum metal

American  

noun

1. any of several bronze alloys with a high tin content, often containing other materials, as silver, brass, lead, zinc, or arsenic, used for making mirrors and reflectors.

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speculum metal British  

noun

1. a white hard brittle corrosion-resistant alloy of copper (55–70 per cent) and tin with smaller amounts of other metals. It takes a high polish and is used for mirrors, lamp reflectors, ornamental ware, etc

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Etymology

Origin of speculum metal

First recorded in 1790–1800

Example Sentences

Mr. Maudslay was interested in the idea I suggested; and he requested me to show him what I knew of the art of compounding the alloy called speculum metal.

From James Nasmyth: Engineer; an autobiography by Smiles, Samuel

When completed, the disc of speculum metal was about six feet across and four inches thick.

From Great Astronomers by Ball, Robert S. (Robert Stawell), Sir

A reflecting telescope of the present day would not be fitted with a mirror composed of that alloy known as speculum metal, whose composition I have already mentioned.

From Great Astronomers by Ball, Robert S. (Robert Stawell), Sir

First: Water, of course, owing to its transparency, possesses not a perfectly reflective surface, like that of speculum metal, but a surface whose reflective power is dependent on the angle � 6.

From Modern Painters Volume I (of V) by Ruskin, John

He was, however, so much annoyed by the treacherously brittle nature of the speculum metal that he abandoned its use, and betook himself to glass.

From Men of Invention and Industry by Smiles, Samuel