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

See Examples For:

speculum metal

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

The great reflectors of Herschel and Lord Rosse, which were provided with mirrors of speculum metal, were far inferior to much smaller telescopes of the present day.

From The New Heavens by Hale, George Ellery

The same precipitate heated to a lower temperature is said to furnish a softer variety of rouge; at all events, it gives one more suitable for polishing speculum metal.

From On Laboratory Arts by Threlfall, Richard

For speculum metal when cold is excessively brittle, and were the casting permitted to cool like an ordinary copper or iron casting, the mirror would inevitably fly into pieces.

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

The above process may be employed for speculum metal, or pitch may be used.

From On Laboratory Arts by Threlfall, Richard