artificial clay (tin al-hikma)

Ingredients

clay

Preparation Steps

Original Recipe Text

Glass vessels used in chemical operations like the 'roasting of substances' were coated with artificial clay (tin al-hikma) to protect them from cracking under intense heat or cooling and to seal joints. Abu Bakr ar-Razi describes 'beakers coated with clay' (qadahan mutaiyanan). This lutum was formulated for extreme heat and moisture resistance and was considered very expensive to produce. (p. 134)

Evidence

"The 'artificial clay' (tin al-hikma) which has the necessary properties (resistance against moisture and heat) and is very expensive to produce was described by al-Kind, ar-R‡z, al-Hw‡rizm and in the Latin Riccardiana manuscript. Known as lutum (English lute), it remained an indispensable laboratory cement until recent times."

Remarks

The museum reconstruction (Inventory No. K 1.49) features a glass retort with a 16 cm high coating of unfired clay. Descriptions of this material are found in the works of al-Kindi, ar-Razi, and al-Hwarizmi, as well as the Latin Riccardiana manuscript where it is called Ampulla lutata. (p. 134)