Scientific American 5, 2.11.1861
George Hallet and John Stenhouse, England, patentees. The native oxyd of antimony, the color of which varies from a light yellow to a yellowish red, consists of antimony, in combination with oxygen, some sulphide, oxyd of iron, silica and frequently arsenic. This mineral is first freed by the patentees from gangue, then reduced to fine powder by grinding and sifting. The powdered oxyd is now placed in large crucibles, and roasted cautiously in a suitable furnace, at a low, red heat, the air being allowed free access. During roasting the ore is stirred occasionally, and it gives off sulphurous acid and arsenical fumes. The process of roasting occupies about three hours, and is known to be complete when no more of the vaports are given off. All the antimony in the ore is now found to be in the state of anhydrous, antimoneous acid. This is reduced to an impalpable powder y grinding and levigating with water. When dried it constitutes a new pigment, and when ground with oil and varnish forms a yellow paint. About eight parts of cure antimony, three of red lead, and one of the ocyd of zinc roasted slowly at a red heat for three hours on the hearth of a reverberatory furnace, makes a good yellow paint also when reduced to powder and mixed with oil.
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