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Rhodium
Rhodium, an odoriferous essential oil, obtained from the wood of a species of the Aspalathus, or African Broom; and which has received its name from the Island Of Rhodes, whence it is said to be imported.
Oil of Rhodium was formerly in great repute as an astringent and corroborant; but, at present, it is chiefly employed in perfuming pomatums; and forms an ingredient in rat-powders composed of poisonous substances; as these noxious vermin are uncommonly partial to the agreeable scent of the drug.
Source: http://chestofbooks.com/reference/The-Domestic-Encyclopaedia-Vol3/Rhodium.html
I find it interesing that they refer to it as “black gold.
Just can’t miss a shot at getting the “black” thing out there.