A new challenge in the lab

I am always pleased to see returning visitors to the Artifact Lab. And of course, people who have been here before want to know, what’s new? Visiting the lab is the best way to find out about our latest projects and progress, but this blog is the next best thing.

So, what is new around here? Well, I’ll let you take a look for yourself:

shabti boxThis object was featured in the “What in the World” series on the museum’s Facebook page this week. There were a wide range of guesses as to what this is; my favorites being a breadbox, an Egyptian mail box, a papyrus organizer, a holder for cat mummies, and an ancient Egyptian Matchbox-car garage.

Seriously though, this is a shabti box. Here is a shabti box that is similar in style, at the British Museum. Shabti boxes were used to house shabti figures. Shabtis were included in burials as servant figures that would carry out heavy work on behalf of the deceased. They were depicted as mummified and were inscribed with spells which, when recited, magically caused them to come to life and perform work for the deceased in the afterlife. Here are 3 shabtis that were originally housed in our shabti box:

shabtisThe shabti box and shabtis are made of wood, covered with a thin layer of gesso, and painted. They are in the lab for treatment because their surfaces are actively flaking. Not only is the paint flaking, but there is a yellow-orange coating over the painted surface that is badly flaking as well.

This yellow-orange coating is applied over the entire surface of the shabtis and the box (inside and out), and it is very thick in areas.

A detail of the shabti box showing areas where the coating is particularly thick (pointed out here with the red arrows).

A detail of the shabti box showing areas where the coating is particularly thick (pointed out here with the red arrows).

My first question is, what is this coating? Is it an original varnish or is it a later restoration?

The box and the shabtis date to the New Kingdom, ca. 1200 BCE. We know that varnishes such as those containing pistacia resin were used on painted wood in the New Kingdom, and these varnishes often appear yellow, although they may not have been yellow when first applied. We also know that these varnishes were applied unevenly – the application of the pistacia resin varnish has even been described as “messy” and it is acknowledged that its purpose was not an aesthetic one, but rather intended to make such objects more divine, or suitable for the afterlife (Serpico and White 2001). This description may help explain the rather sloppy appearance of the yellow-orange varnish on our shabti box and figures.

We cannot, however, discount the idea that this coating may be a later restoration. We know that archaeologists frequently stabilized artifacts in the field to allow for their safe recovery. Materials such as paraffin wax, gelatin, shellac, and cellulose nitrate have been used for this purpose in the field or once the objects found their way into museum collections (like the wooden heads Laura has been working on).

There are several ways in which we can try to determine what this coating is and when it may have been applied. We already have some clues, but we’ll share those in an upcoming post. Stay tuned for updates as we learn more!

 

Flippin’ coffins

We’ve been threatening to do it, and this week we followed through on our promise – to flip over the base of Tawahibre’s coffin.

As readers know, we have been working on Tawahibre’s coffin lid, and recently lifted it away from the base. Once we removed the lid, we could see that the interior of the base was undecorated, with plaster smoothed over the wood joins. There was also some textile remaining, presumably from the mummy who once was inside.

inside tawahibre

An interior view of the base of Tawahibre’s coffin

While the interior is undecorated, we know the same isn’t true for the exterior, based on a photo recovered awhile back in the Archives. After a bit more digging in Archives recently, we found even more detailed photographs of the coffin lid and base, taken sometime before they were put on exhibit back in the 1930s.

tawahibre front and back

Image from the Archives showing the front of the coffin lid and the back of the coffin base

Recovering old images like this is exciting because they potentially have a lot to tell us. In this case, this photograph is a good record of what the condition of the coffin was like soon after it was acquired by the museum. Like in the exhibit photograph I had recovered earlier, I could see that a lot of the damage we’re seeing on the coffin lid today was present then. But there was no way of knowing, until this week, how the current condition of the coffin base compares to the condition seen in this photograph.

And I have to tell you, I was a bit worried – until just a few days ago, all I could see of the coffin base was from these views:

Detail views of the proper right and proper left sides of the coffin lid and base, before treatment

Detail views of the proper right and proper left sides of the coffin lid and base, before treatment

Those large chunks of plaster and paint on the wood support below weren’t very promising. I had a sinking feeling that a lot of the paint and plaster on the back of the coffin base was unstable as well, and going to fall away when we tried to lift and flip it over.

The first step in getting the coffin base flipped over was to stabilize the plaster and paint on the inside and sides of the base, as much as possible. I carried out this work using the same methyl cellulose adhesive solution and fill material mixture as I have been using on the lid.

Then we did a test lift, to see how stable it felt, and to determine if we needed to temporarily stabilize any areas on the back before turning it over.

test liftThe test lift was encouraging, so we decided just to go for it!

How many conservators do you need to flip over a coffin base? Eight, it turns out.

flipping over1Fortunately, the procedure went smoothly, smoothly enough that we even allowed our Public Relations Coordinator Tom Stanley post a video of us turning the base over on the museum’s Instagram account.

Once we turned the base over, we were rewarded by being able to see that the back is still remarkably well-preserved, with very little changes from when that old photograph was taken:

Tawahibre's base in the 1920s (left) and today (right)

Tawahibre’s base in the 1920s (left) and today (right)

Can you spot the differences in these two photographs? I’ll post another copy of this image soon, circling the changes that have occurred.

 

Looking inside our falcon mummy

Last Friday, 7 of us from our conservation department took a group of objects from the museum to the GE Inspection Technologies Customer Solutions Center in Lewistown, PA for x-radiography and CT scanning.

Our group gathered around the CT scanner, being operated by Becky Rudolph, GE's North American Radiography Sales Manager for Academia

Our group gathered around the CT scanner, being operated by Becky Rudolph, GE’s North American Radiography Sales Manager for Academia

Now, wait just a second, you might be thinking. Doesn’t Penn have its own x-ray and CT scanning equipment? Why did we have to take these objects all the way to Lewistown for this work? Good questions, and we have a good answer. We just received word that in early 2014, construction will begin on our new conservation labs, which will include a digital x-ray suite. We plan to purchase the x-ray unit from GE, so a visit to their facilities was a chance for us to demo the equipment using some of our own artifacts!

The object I was most eager to image was our falcon mummy. X-ray and CT (computed tomography) scanning technology allow us to “virtually unwrap” this mummy, helping us understand how it was made and what is inside (and as visitors to the lab have heard me say, we can’t assume that there are any falcon remains inside-we can only hope!).

The falcon mummy laying on its storage support on the x-ray plate (within a lead-lined room)

The falcon mummy lying on its storage support on the x-ray plate (within a lead-lined room)

The quickest way to get a peek inside the falcon mummy’s wrappings is by taking an x-ray image. Digital x-ray technology is amazing – with a push of a button, 135 kV (kilovolts, measurement of the voltage), 2.0 mA (millamperes, measurement of the current) and 4 seconds later, we saw this:

falcon xray annotatedHooray! In this first attempt, we could already see that there are bird remains inside. The bright white material concentrated in the center of the mummy wrappings is the skeletal remains. In radiographic images, materials that are denser appear white because they do not allow x-rays to pass through. Materials that are less dense (such as the textile wrappings surrounding the bird bones) appear darker, because the x-rays are penetrating and passing through these materials. We can see in the image above that there are no skeletal remains in the “head” and the “feet” of the falcon mummy – these areas appear to have been sculpted with fabric. The slightly brighter white area near the feet just reflects an overlap of textile in that area.

While we were excited by this image, it immediately prompted more questions. We can see bird bones, but where is the skull? How much of the bird body is present? Are there any clues as to how the body was prepared for mummification? To answer these questions, we turned to the CT scanner.

CT scanning uses x-rays to produce cross-sectional images of an object, which can then be combined to produce three-dimensional views. CT provides a much more detailed look inside objects, and better distinction between different materials.

The CT unit at GE does not look like a medical CT scanner that many people may be familiar with. To scan the falcon, we had to stand the mummy upright in its box, which we then secured to the rotating stage inside the CT chamber with masking tape.

Right: Lynn Grant and I taped the falcon mummy in his box to the stage inside the CT chamber. Left: another view of the falcon mummy's box secured inside the CT chamber.

Left: Lynn Grant and I taped the falcon mummy in its box to the stage inside the CT chamber Right: another view of the falcon mummy’s box secured inside the CT chamber

The CT scanning took a bit longer than 4 seconds, but again, produced much more detailed images. Here is what one of the cross-sections looks like:

falcon cross section annotatedIn this image, the bones are visible as the most radio-opaque materials (so they are bright white). We were also excited to see the feathers, clearly visible as little circles reflecting the cross-section of the feather shafts, which are hollow. The various layers of linen wrapping are also very clear – clear enough to count! But other details are not so immediately clear to us, including the presence of the skull, and exactly how the remains were prepared.

Here is a screen shot from the program we are using to view the CT images, showing 3 different cross-sections, and a basic 3D rendering of a section of the falcon mummy. In this 3D rendering, we can clearly see the falcon’s talons, circled in red!

falcon CT 3 views annotatedWe will need to spend time with the images, and consult other specialists, to better understand what the CT scans have revealed.

image_2

UCLA/Getty graduate intern Alexis North and I puzzle over the CT images of the falcon mummy

We will follow up later with more images and interpretations of the falcon mummy CT scans, plus more about the other objects we were able to examine.

A special thank you to Becky Rudolph and Hank Rowe at GE for spending the day with us, and for their expertise!

 

X-ray excursion

If you stopped by the Artifact Lab this week, you might have noticed that our falcon mummy is no longer on display, and this sign in its place:

falcon signAs indicated on the sign, the falcon has been removed for x-radiography. This mummy has never been x-rayed before, and we’re interested in using this imaging technology to learn how it was made and if there are any falcon remains inside!

Along with the falcon, we’re also going to be x-raying/CT-scanning our (possibly headless) cat mummy, the wooden statue heads, and several other pieces.

We do not have the ability to x-ray and CT-scan objects here in the museum, so we will be taking these selected pieces for a little trip tomorrow. In preparation for their travels, they are securely packed, and ready for this exciting excursion!

The falcon mummy is secured inside its storage support and packed into a larger box for travel.

The falcon mummy is secured inside its storage support and packed into a larger box for travel.

We will update the blog with our findings soon after we return.

 

A new face in the lab

Last week I introduced you to our baby boy mummy, and this week I have another introduction to make. But unlike most of the Artifact Lab occupants, our newest addition is very much alive! Laura Galicier is a graduate student studying conservation at the University of Paris Pantheon-Sorbonne, and she recently arrived in Philadelphia to start a 7-month internship In the Artifact Lab.

Laura_microscope

Laura examining a wooden statue head under the binocular microscope

A couple of the things that you may wonder are, did she know that this internship would involve being on display all of the time, and, as a conservator-in-training, how does she feel about having to answer so many questions about Egypt? Well, the answer to the first question is that she was very well-aware of the open nature of the lab because she found out about us through this blog, and had seen photos of the lab and read about our daily interactions with the public. So she can’t say that she didn’t know what she was getting herself into!

Laura_openwindow

Laura is a quick-study, and is already doing a beautiful job of fielding questions from visitors during our open window sessions.

Furthermore, Laura is more knowledgeable than most conservators about Egypt, because before starting her conservation studies, she completed a Master’s in Archaeology with a specialization in Egyptology. She has also worked in Egypt, at the Karnak Temple Complex.

While she is here at the Penn Museum Laura will be working on several projects in the lab, one which will be the subject of her dissertation. I’m not going to say anything else about it here – I will let Laura tell you all about her work in an upcoming blogpost. In the meantime, I hope your curiosity is piqued by these images (above, at the microscope, and below) of her examining a pair of wooden statue heads. Expect to hear more about them from Laura here on the blog, and if you visit the lab, you may have a chance to chat with her about her projects.

Laura_pxrf

Laura positioning a wooden statue head under the portable x-ray fluorescence analyzer (pXRF)

Examinations of a baby boy mummy

I think it’s about time we introduce you to a special occupant of the Artifact Lab.

This baby boy mummy, who dates to the Third Intermediate Period (1075-656 BCE), has been in our collection since 1898, when he was donated to the museum by Dr. Henry Shurtleff.

Photograph of the baby boy mummy from the museum Archives

Photograph of the baby boy mummy ca. 1930

In the University’s 1898-1899 Annual Report of the Provost to the Board of Trustees, it states that Dr. Shurtleff presented the infant mummy to the museum on Christmas Day, as an “admirably preserved specimen and an interesting pathological subject”.

It seems that this mummy came into the collection unwrapped – he only has small amounts of textile preserved on his body (and there is currently no evidence that the cloth partially covering his body in the image above is related to his remains, but this remains to be determined). While the fact that he is unwrapped is unfortunate, it allows us to see how well preserved his remains are and evidence of how his body was mummified, including evisceration through an incision on the left side of his torso.

The open incision on the left side of his body reveals a mostly empty body cavity, containing small bundles of linen.

The open incision on the left side of his body reveals a mostly empty body cavity, containing small bundles of linen.

A CT scan in 2009 further reveals how this boy’s body was mummified, and also reveals damage not visible from the exterior. For example, it is clear that his brain was removed, likely through the nose (but due to the small side of his nasal bones it is not possible to see evidence of this). The scan also reveals a large hole in the left lower side of his skull, and the piece of missing bone resting inside his skull.

Two CT still images show the child mummy's skull with a piece of bone resting inside the cranium (left) and the hole on the lower left side (right).

Two CT still images show the child mummy’s skull with a piece of bone resting inside the cranium (left) and the hole created as a result of this loss (right).

Oddly, this damage to his skull is not visible from the exterior, but it may be the result of trauma. His cause of death has still not been determined, but this damage may provide a clue.

The information from the CT scan tells us that this child was less than 2 years of age when he died, based on the fact that his fontanelle (the soft spot) is still open, and also on the development of his teeth.

The open fontanelle on the top of the baby's head is indicated in these 2 images with blue arrows.

The open fontanelle on the top of the baby’s head is indicated in these 2 images with blue arrows.

The excellent preservation of his body is not the only remarkable thing about this baby boy. While examining his remains, we noticed traces of a green substance in areas, including on his face and fingers.

A detail of the green substance under the boy's right eye (left) and an overall view of the boy's face, highlighting the locations of the green substance in green (right)

Left: A detail of the green substance under the boy’s right eye. Right: An overall view of the boy’s face, highlighting the locations of the green substance in a brighter green color.

This substance resembles copper corrosion, and it may either be corrosion from copper that was once in contact with his body (during burial), or may be traces of a green copper-based pigment. How do we know this green substance is copper-based? We tested it with our portable x-ray fluorescence analyzer, which showed high peaks for copper in these areas.

While we’re still working to interpret some of this information, I can tell you one thing for certain: this baby boy mummy sure is special. And if you visit the lab, you just might catch a glimpse of him.

 

Wrapping up the cat mummy

Speaking of Abydos, let’s get back to our cat mummy, which was excavated from a cemetery there back in 1901-02. Our summer intern Anna O’Neill will describe how she carried out the conservation treatment on this very fragile object:

Hello again.  You may remember that last time I wrote about this cat mummy, I got a little distracted.  But this time I’d like to focus on the treatment process.  Many of our mummies are in remarkably good condition, with wrappings that are stable and that can withstand handling (albeit with care).  Not so with this cat.

cat mummy 1When plant-based fibers age, the cellulose that gives them structure decays and the fibers become brittle.  Badly aged linen can fall apart at the lightest touch, leaving loose fragments and powder on the surface of the object.  The linen on top of this cat mummy was torn and obscured by dust, but the real problem was underneath.  Prior to treatment, Molly and I carefully turned the mummy a little so we could see below—and quickly (but gently) put it back!  As you can see in the image below, the layers of linen were falling apart and the threads that had criss-crossed the layers were broken and hanging off.

cat mummy 2We decided to wrap the mummy in nylon netting, which would hold everything in place while keeping the surface visible.  This would be a non-invasive, completely reversible process that would allow the mummy to be safely handled and studied.

Before wrapping, I gave the mummy a light surface cleaning with a variable-speed HEPA-filtered vacuum.  Using a nozzle attachment fitted with a screen, I carefully removed the powder on the top of the mummy.  The linen—though torn—was still soft and flexible, like modern fabric.

cat mummy 3Then, I toned the netting to match the color of the mummy using acrylic paint.  Once the paint was dry, I positioned the netting across the top of the mummy and pinned it in place.  The flip was simple but nerve-wracking—we knew from our quick peek earlier that the underside was in bad shape, but we didn’t know to what extent.  With Molly’s help, I turned the mummy over so that all of the powder, torn linen and broken threads were now on top.

cat mummy 4Since the thick layer of compressed linen powder completely obscured the wrappings below, I again vacuumed the mummy, using a screen to filter out the powder while keeping everything else in place.  A vacuum may seem like an odd conservation tool (I got some weird looks as I hoovered the cat), but with the filter over the nozzle and variable suction control, there’s no danger of sucking up the entire object.

cat mummy 5

The underside of the mummy after cleaning. It may not look like much, but it’s better!

With the underside of the cat finally visible, I sewed the netting up the middle using a flat-felled seam.  As the name implies, this created a neat seam with a flat profile.

cat mummy 6

Overall view of the underside of the cat mummy (after treatment)

Overall view of the top of the cat mummy (after treatment)

Overall view of the top of the cat mummy (after treatment)

Now that the linen wrappings are encapsulated, the little cat mummy can be handled and studied, and it can (hopefully) be x-radiographed this fall.  It still may not have its head, but at least it won’t be losing any more of itself any time soon.

 

A final report from Abydos

Back in June, we provided an update from the Penn excavations at the mortuary complex of Pharaoh Senwosret III in Abydos. The team has since returned from the field, and graduate student Kevin Cahail generously passed along some photos showing what the project looked like as they were wrapping up in the field. Just as a reminder, the project has concentrated on three principal areas: (1) the subterranean tomb of pharaoh Senwosret III; (2) the mortuary temple and associated structures dedicated to the cult of Senwosret III; and (3) the urban remains of the Middle Kingdom town at South Abydos. You can read a bit more about the project in our first post.

After excavations are complete, the team documents the site by setting up a huge wooden ladder in the middle of the desert, climbing up it, standing at the top, and taking photos. Kevin mentioned that its a great view, but that he did have to put quite a bit of trust into his Egyptian compatriots to hold the ladder steady.

01 Site Photo MethodAnd this is what the view looks like – here is a shot of part of the Cemetery S excavations of 2013:

02 Cemetery SThe mound in the background is mastaba S10 of the Late Middle Kingdom. Three tombs are visible from left to right, CS.8, CS.4, and CS.5. These three tombs date to the New Kingdom.

Following their excavations in the town site of Wah-sut, grad students Paul Verhelst and Shelby Justl are seen here drawing brick plans of the exposed architecture:

03 Paul and Shelby  drawingIn the background the workers begin the process of backfilling the excavated areas.

This shot shows the excavations in the Temple Cemetery, Tomb TC.19:

04 TC19 excavationThis one-room vaulted tomb with a rectangular entrance shaft had been looted in the months before the team arrived in 2013. Despite this, they did recover a fragment from a yellow-type coffin showing the lower portion of some standing gods:

05 TC19 Coffin fragand a wooden coffin hand applique with painted rings:

06 TC19 Coffin handThe last tomb they excavated was TC.20, a tomb which the team discovered belonged to a Scribe by the name of Horemheb.

07 TC20 OverviewTo the left is an overview of the tomb showing a heavy-walled entrance shaft, an antechamber, and in the foreground, the burial chamber.

A third vaulted chamber to the right below the sand remains unexcavated.  The team plans to tackle this next season.

 

 

 

 

 

 

To give you a sense of the size of this tomb, here is a photo of Joe Wegner taking a photo of Kevin from inside TC.20.  Kevin is standing in the entrance shaft, and Joe is in the burial chamber:

08 Joe in TC20And here is a final group photo of the excavation team standing on the recently completed cover building over the tomb of Senwosret III:

09 Final Group PhotoIt was a busy field season and the team intends to return this winter, conditions permitting. We will continue to provide updates on this blog as their project progresses!

 

Opening Tawahibre’s coffin

I don’t think many people will argue with me about this – a day at work (heck, a day in my life!) can’t really get more exciting than opening a 2500+ year old Egyptian coffin. For the last several months, we have been carrying out treatment to stabilize the loose wood, crumbling gesso, and flaking and powdery paint on the lid of Tawahibre’s coffin. While there is still a lot of aesthetic work to carry out, we finally got the lid to a point where we deemed it stable enough to remove it from it’s base.

Removing the lid from an incredibly fragile 2500+ year old coffin doesn't happen without a lot of planning and discussions ahead of time.

Removing the lid from an incredibly fragile 2500+ year old coffin doesn’t happen without a lot of planning and discussions ahead of time.

Okay, okay, so, the coffin has been opened before, and we knew that there wasn’t a mummy inside anymore (she’s down in storage), but opening the coffin was monumental nonetheless, as the lid hadn’t been removed in decades and we didn’t really know what we would find inside.

Fortunately, we were able to lift and move it without any problems:

DSC_0765DSC_0771DSC_0776(they really make it look like a breeze, don’t they?)

And now the lid is safely resting on a new palette, and the interior of the coffin is revealed to us for the first time:

Tawahibre lid and base separated

Yup, just another day in the Artifact Lab. We’ll fill you in later about what we’re learning and what’s going to happen next.

 

 

The 2013 Mummy Congress in Rio de Janeiro

Today we are featuring another guest-blogger: our pre-program conservation intern Melissa Miller. Melissa just returned from a pretty special mummy-related trip – read on to hear more about it!

From August 6-9th, I had the opportunity to travel to Rio de Janeiro, Brazil and attend the 8th World Congress on Mummy Studies.

IMG_2766This biannual conference brings together experts from all over the world to discuss recent and ongoing mummy research projects.

Mummy studies draw in a surprising variety of disciplines. There were experts in physical and cultural anthropology, conservation, paleopathology, paleoparasitology, dentistry, medicine, radiology and more. I listened to presentations on ancient DNA techniques, publishing e-books, parasites in coprolites, archaeological excavations in the Valley of the Kings, genetic analysis of the Iceman, and the list could go on. For 4 days I received a crash course on numerous mummy research projects from all over the world that have been going on for the last 15 years. Thankfully the Congress was videotaped and I will be able to revisit some talks or view some that I was unable to attend due to conflicts with other presentations.

melissa mummy congressWhile there, I was also able to present a poster on my ongoing research into the history and development of autopsied mummies, and the preservation of generated materials. For me this was perhaps the most valuable part of my experience at the Mummy Congress. Simply meeting all of these incredible and passionate people and listening to their advice, hearing their encouragement and seeing their willingness to help me continue my research was invaluable. Some have also granted me permission to interview them!

Looking towards the future, I plan to continue my research throughout the academic year and develop my senior thesis. Perhaps by the time the 9th World Congress rolls around I will be able to present my finished project!  Lastly, I would like to say that I am very grateful to all those at the University of Delaware and University of Pennsylvania Museum of Archaeology and Anthropology who made it possible for me to attend the Mummy Congress, and to all those at the Mummy Congress who offered their great advice and support.