Among the most historically rich recipes from ancient Mesopotamia are the instructions for making glass imitations of precious stones. To date, we have recorded over 1200 semantic interactions, which have greatly aided our understanding of the technical terminology of ancient glass-making. However, it was not the technical terminology of Assyrian glass-making that first attracted scholars to these texts.

In the mid-1920s, Assyriologists (philologists specializing in cuneiform) and scholars of the ancient world engaged in a heated debate concerning the historical beginnings of the eld of chemistry. When they encountered clay tablets from ancient Mesopotamia containing instructions for making glass, these scholars split into two groups. the first group characterized the cuneiform glass-making recipes as “chemical” and the second group as “alchemical.”

Much of the debate between these two groups hinged on one particular term, a deity known as Kūbu, to whom sacrifices are made on the day that glass is to be made in a kiln. For those in the “alchemical” group, Kūbu were interpreted as homunculi (an artificially made humanoid known from later alchemical texts). According to our reading, Kūbu are to be understood in both magical and metaphorical terms; their purpose was to maintain the glass-making process free of physical (and metaphysical) impurities, as indicated in the writing of Kūbu itself, which utilizes the cuneiform sign for purity, ku3 𒆬.

Read a glass making text by clicking the tablet below:

ASSYRIAN ALCHEMISTS?

Cuneiform Glass-making Recipes

glass | perfume | wool

SMELL LIKE A KING

Middle Assyrian Perfume-Making Recipes

When you lay the foundations of a glass-making kiln, you search repeatedly for a suitable day during a favorable month, so that you may lay the foundations of the kiln. As soon as you complete (the construction of) the kiln, you set down Kūbu demons in order that an outsider or stranger cannot enter; one who is impure cannot cross their (Kūbu demons’) presence. You will constantly scatter aromatics offerings in their presence. On the day that you [set down] “glass” (lit: "stone") within the kiln, you make [a sheep sacrifice] in the presence of the Kūbu demons, (and) you set down a censer (with) juniper (you ...) honey. You (then) ignite a fire at the base of the kiln. You (may now) set down the “glass” within the kiln. The persons that you bring close to the kiln must be purified, (only then) can you allow them to sit near (and overlook) the kiln. You burn various wooden logs at the base of the kiln (including): thick logs of poplar that are stripped, and quru-wood containing no knots, bound up with apu-straps; (these logs are to be) cut during the month of Abu; these are the various logs that should go beneath your kiln.