Conserving a Seleucian Incantation Bowl

BY MADELEINE NEIMAN, 2014–2015 Samuel H. Kress conservation fellow at the Kelsey Museum. During her time here, Madeleine’s work will focus on the technical analysis and treatment of objects from the Seleucia collection.

The vessel was excavated in the 1930s from Seleucia on the Tigris, a site approximately 18 miles south of modern-day Baghdad, Iraq. Magical bowls like this one were placed in the corners of houses or under thresholds as a means to protect their owners from evil spirits. The text and images drawn served to combat demons or other supernatural beings that might harm the object’s owner. Today incantation bowls, including this one, are important for the study of ancient magical and religious practices.

Can you guess why the bowl came to the conservation lab?

How about if you compare it to another incantation bowl in the Kelsey collection?

Yes. That’s right. There is a thick, dark crust covering much of the interior and exterior of the bowl, and it hides the decoration on the bowl’s surface. Curators here at the Kelsey have asked the conservation lab to remove the crust so that the decoration on the surface is easier to see. Before the crust can be removed, however, conservators must figure out what this strange material is.

Based upon a close examination of the surface, we suspect the crust is most likely one of two things.

Option 1: Salts! This bowl was buried under ground for approximately 2,000 years.  During that time the porous ceramic vessel was likely exposed to groundwater containing a range of salts; chlorides, nitrates, phosphates, and sulfates are all commonly present in soil and are, as a result, often found within the fabric or on the surface of ceramics recovered from archaeological contexts. While salts typically appear as areas of white crystalline efflorescence on an artifact, they may also occur as dark, hard surface accretions similar to the material visible on the bowl.

Option 2: A modern coating. It is possible that the darkened surface is due to the application of a modern coating.  During the 1930s, when this object was excavated, archaeologists and conservators often covered artifacts with a resin or glue in an attempt to protect and strengthen surfaces. While these materials were applied with good intentions, they can alter over time in unexpected and undesirable ways. A once clear, coherent coating could become dark and brittle like the coating on the bowl.

However, as Sir Arthur Conan Doyle notes, “it is a capital mistake to theorize before one has data.” So … how will conservators here at the Kelsey get the data necessary to determine what is covering the bowl?

Like historians, conservators look at archival records. The Seleucia archive at the Kelsey Museum holds a range of primary source documents created by archaeologists at the time of excavation, including journals, object lists, and photographs. We will examine these documents for any clues to what the bowl looked like at the time of excavation (e.g., was the bowl’s surface dark when removed from the ground?) as well as the conservation methods that might have been used on the bowl. We will also utilize a range of scientific examination techniques available across the University of Michigan campus to study the chemical makeup of the crust.

I hope you will check back with us in the coming months as we work to uncover the surface of this bowl.