The Encyclopedia of Founding

Twelve hundred entries from the golden age of cast metal — how bells are founded, why brass is not bronze, what a cupola melts and a core withstands — by Simpson Bolland, the trade's great teacher.

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Umber

A variety of hematite ore, composed of oxide of iron 48, oxide of manganese 20, silex 13, alumina 5, water 14. It is found in Cyprus; occurs massive; has no lustre; is brown and yellow in color; becomes a reddish brown when burnt, and in that state is used as an artist's color.

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