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Rolled gold is made by casting an ingot of brass, and while this is still
hot pouring upon it a thin layer of gold alloy. The ingot when cold is
forced between steel rollers until a long, thin ribbon is produced, of
which the proportion of gold and brass is the same as of the ingot. The
percentage of gold is reduced as low as two and three per cent. This
rolled gold is used in making cheap bracelets and watch chains. It wears
from one to ten years.
A CATALOGUE, containing brief notices of many important scientific papers
heretofore published in the SUPPLEMENT, may be had gratis at this office.
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The Scientific American Supplement.