Spuma di ferro

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From Gibbs' "Instructions for the treatment of negroes", 1786.

"A RECEIPT to make an Italian Compoſition for floors:
Calcina virgine - Unſlacked lime
Geſſo di preſa - Chalk.
Polvere di mattone - Brick-duft.
Spuma di ferro, ben peſto. - Froth of iron finely powdered.

The Spuma di ferro, or the froth of iron , is a ſponge-like ſubſtance, which is thrown up in ſmelting the Ore".

As a substituion for the froth of iron, the author suggested smith cinders.
What is the contemporary term for this substance? I failed to find anything definite neither for spuma di ferro nor for the froth of iron. And my only guess is slag/scoria.
  • Maroseika

    He says it should be powdered before using, so initially it's not in the form of powder.
    And if you mean filings obtained when sawing the metal, it also is not the case, since he says it's obtained immediately when smelting ore.


    Senior Member
    Italian from Italy
    Hello Maroseika!
    I was very interested in this topic and found a recipe for 'spuma di ferro', made by an alchemist.
    Obviously, the Italian is that of the 15th century.

    Personally, I would translate it as 'iron foam', explaining that it is an alchemical mixture. In a nutshell, it is a mixture of sieved filings mixed with wine must and then heated until it reaches the viscosity of honey. So it is written below, at least.

    Give a look below:


    Last edited:
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