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

L. M. Rutherfurd introduced into common use the reflection grating, finding that speculum metal was less trying than glass to the diamond point, upon the permanence of which so much depends.

From Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 4 "Diameter" to "Dinarchus" by Various

Even glass, brittle though it be, is strong in comparison with speculum metal of the above proportions, though, as I have said, it yields the most brilliant composition.

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

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

In speculum metal there are 2 to 2� parts of copper to 1 of tin.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" by Various