Invisible ink (laban and nushadir)
Egypt
13th Century
Source: Raggetti, L. (2023). Ordinary Inks and Incredible Tricks in the ʿUyūn al-ḥaqāʾiq. Brill.
Recipe Details
Ingredients
sour milk, sal ammoniac (nušādir)
Preparation Steps
A mixture of sour milk and sal ammoniac (nušādir) is used to write a secret message. To reveal the text, the recipient must place the paper near a fire (p. 180).
Original Recipe Text
A mixture of sour milk and sal ammoniac (nušādir) is used to write a secret message. To reveal the text, the recipient must place the paper near a fire (p. 180).
Evidence
"Take some sour milk and sal ammoniac, write a message with it... When you place it near to the fire, the writing will appear."
Remarks
In Witness B, 'sal ammoniac' is substituted with the code name (Deckname) 'the eagle' (al-ʿuqāb) (p. 180).
Scientific Analysis
Chemical CompositionNH4Cl (sal ammoniac)
Analytical Techniques
Philological analysis
Certainty Level
Inferred
Instrumentally Verified
Not Verified
Metadata
Material Type
ink
Bindersour milk
RegionEgypt
Approx. Year1250
Source Information
AuthorRaggetti, L.
CollectionKitāb ʿuyūn al-ḥaqāʾiq
Language
N/A
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