Cats and Bears

Contributed by John Bergman-McCool

Lately, the process of fully cataloging Adopt-A-Drawers has resulted in some interesting discoveries. The most recent of these comes from artifacts collected by Richard “Scotty” MacNeish in Tamaulipas, Mexico.

MacNeish went to Tamaulipas in 1945 hoping to find sites that predated the production of ceramics. In particular, he was searching for sites with long cultural sequences that he could use to tell the story of the development of human culture in Mesoamerica. During three field seasons, spanning  ten years, MacNeish identified and excavated several village and cave sites in the Sierra de Tamaulipas and the Sierra Madre Oriental, two mountain ranges in Tamaulipas.

MacNeish’s Tamaulipas excavation areas.

MacNeish recovered a wide variety of items from the well-preserved cave deposits in Tamaulipas. Of these were two fragmentary bear canine-shaped pendants recovered from Armadillo Cave in the Sierra de Tamaulipas. They appear to have been burnt and MacNeish believed that they were fashioned from sandstone. When compared with real canines from a bear and unknown canid, it is clear that they are an imitation. For example, the Tamaulipas pendants have no enamel and they lack the same degree of detail. However, they do approximate the shape very effectively.

Left: Two Tamaulipas bear canine-shaped pendant fragments. Middle: Dog or coyote canine pendant from Ohio. Right: Bear canine pendant from Ohio.

One of the pendants was fractured below a possible enamel layer so they were both inspected under magnification. Surprisingly, they show signs of very thin layering more reminiscent of the annuli of shell. I asked our Director, Dr. Ryan Wheeler to take a look at them. Among those who work here at the Peabody, he is the resident expert on shell artifacts. Dr. Wheeler agreed they were shell.

Magnified View of bear canine-shaped pendant from Tamaulipas, showing annuli.

The fact that the pendants were made of shell led us to think about a possible connection with the Hopewell Culture. Several shell imitations of bear canines have been recovered from Hopewell mound sites. Additionally, the Hopewell developed a very large interaction sphere, traveling far and wide for trade materials. The Hopewell procured copper from Lake Superior, silver from Canada, obsidian from Wyoming, mica from the Blue Ridge Mountains and shell from the Gulf of Mexico.

We wondered if these pendants could have been a Hopewell trade object. Fortunately, the Peabody archives include MacNeish’s Tamaulipas excavation paperwork (digitized here). The first step to establishing a possible link was to determine the items’ age. Using charcoal from distinct layers excavated from the cave deposits, MacNeish was able to radiocarbon date the deposits. The layer containing the shell pendants dates to the Almagre Phase, roughly 2,200 to 1800BCE. This correlates to the Archaic period in the Ohio valley, about 2,000 years before the Hopewell developed. The Hopewell connection was out.

I also searched for bear remains found in northern Mexican archaeological contexts. A very quick review of available resources indicated that bear remains are not all that common in the region. The only positive return came in the form of bear long bones found at Casas Grandes in Chihuahua, Mexico. This was interesting, because the historical range of both Mexican grizzly and black bears include much of northern Mexico, including Tamaulipas state. It is very likely that humans and bear interacted in the past.

At Dr. Wheeler’s suggestion I reached out to Dr. Brad Lepper, Senior Archaeologist with the Ohio History Connection and José Luis Aguilar Guajardo, archaeologist in Tamaulipas, Mexico. They both responded with helpful information. Dr. Lepper was interested in the presence of the shell pendant and was unaware of anything similar coming from Archaic sites. He suggested consulting Cheryl Claassen’s book Beliefs and Rituals in Archaic Eastern North America for possible archaic examples, which I haven’t yet had a chance to read.

Dr. Lepper provided several examples from the Ohio History Connection’s collection of Middle Woodland Hopewell bear canine pendants (here and here) and their imitations (here and here). Some of the canines were split, or contained fresh water pearls from the Ohio River. Imitations were made from mica, copper, shell, bone, ceramic and stone.

José Luis Aguilar Guajardo was also very interested in the bear canine-shaped pendants. He was unaware of anything similar coming from sites in the Sierra de Tamaulipas mountains. He indicated that shell was a semi-precious material used for making ornamentation by the Indigenous people in the area. The Sierra de Tamaulipas mountains are quite close to the Gulf of Mexico, a source for shell materials.

José was clear that black bears can still be found in the Sierra de Tamaulipas, and supported the possibility that they were bear-shaped. However, he suggested the possibility that they were inspired by the jaguar instead. According to José, jaguar were abundant in the area and were revered by the Indigenous people.

How to assign an animal label to the pendants becomes an interesting problem. Bear and jaguar canines can look similar in size and appearance. Understanding what the maker of the pendants intended them to represent is difficult when they cannot be asked about them directly. Both animals’ habitats overlapped in northern Mexico.

Though they don’t provide a definitive answer, some helpful articles, and their authors, that explore the importance of bear and jaguar imagery in north and Mesoamerica include: Bear Imagery and Ritual in Northeast North America, Thomas E. Berres, David M. Stothers and David Mather; Predators of Culture: Jaguar Symbolism and Mesoamerican Elites, Nicolas J. Saunders; and Rohonas and Spotted Lions: The Historical and Cultural Occurrence of the Jaguar, Panthera onca, among the Native Tribes of the American Southwest, Steve Pavlik. There are probably many, many others.

Perhaps, as José Luis Aguilar Guajardo has suggested in personal communications, Sierra de Tamaulipas falls into an area in which jaguars were strongly revered. In a very simplistic summary of the above articles, cranial remains of bears in archaeological contexts in North America have been considered a sign of bear ceremonialism. They don’t appear in MacNeish’s Tamaulipas excavations. Jaguar hides were an element of Aztec royal clothing and one of the accoutrements used by Aztec shamans. A small fragment of possible jaguar hide was recovered from the Sierra Madre excavations in Tamaulipas.

Future excavations in the area will likely bring more evidence to bear on the ritual and symbolic practices of the people of Tamaulipas.

Resources:

Archaic Bear Tooth Pendants and other related artifacts

Donaldson, William S. and Stanley Wortner

1995      The Hind Site and the Glacial Kame Burial Complex in Ontario. Ontario Archaeology 59:5-95.

Bear Imagery and Ritual

Berres, Thomas E., David M. Strothers and David Mather

2004      Bear Imagery and Ritual in Northeast North America: An Update and Assessment of A. Irving Hallowell’s Work. Midcontinental Journal of Archaeology 29(1):5-42.

Jaguar Imagery and Ritual

Pavlik, Steve

2003      Rohonas and Spotted Lions: The Historical and Cultural Occurrence of the Jaguar, Panthera  onca, among the Native Tribes of the American Southwest. Wicazo Sa Review 18(1):157-175.

Saunders, J. Nicolas

1994      Predators of Culture: Jaguar Symbolism and Mesoamerican Elites. World Archaeology  26(1):104-117.

An Unusual Item

Contributed by John Bergman-McCool

Recently, an unusual item was found while processing one of our adopted drawers. The Adopt-A-Drawer program lets donors support the full cataloging of artifacts housed at the Peabody. Every time a drawer is adopted we measure, weigh, photograph, and house the contents in archival storage. Beyond documentation and storage, adopted drawers represent a chance to dig deeper into the stories of the items held here at the Peabody.

Figure 1. Example of an unmodified turkey ulna (top) and flute made from ulna.

The item in question was one of two bone flutes stored in the adopted drawer (figure 2). According to our catalog, they were both from Pecos Pueblo, a site in New Mexico situated in the Upper Pecos Valley east of Santa Fe. One of the flutes is labeled with a number that indicates that it was previously uncataloged and found with material from Pecos. At some point in the past, it had become separated from its provenience information.

When comparing the two flutes they are similar in most ways. They are both made from bird bones with the ends removed to make a hollow tube (sound chamber) that is open on both ends. They also share the same configuration of holes. There is a larger hole near the proximal end of the bone and three smaller holes at regular intervals near the distal end of the bone.

Where they differ is that the uncataloged flute’s sound chamber is plugged at the proximal end by a dark material with a vitreous luster. It immediately brought to mind resin, an Indigenous adhesive material that I knew of but had never seen in a decade of working as an archaeologist. The position of the plug suggested that this instrument was played like a transverse flute, which was eye opening.

Figure 2. The two flutes with view of openings at proximal end.

­I looked for information on other flutes from Pecos and fairly quickly came across an article authored by Richard W. Payne for Kiva, an archaeological journal published by the Arizona Archaeological and Historical Society. Mr. Payne was a trained medical professional with a lifelong interest in Native American flute music. You can find more information about him here and a bibliography of his writings on native flute traditions here. He is considered one of the driving forces behind the rejuvenation of the Native American (or Plains) flute, which is its own fascinating story (Conlon 2002).

Payne’s article is fairly technical, being written from the perspective of a person with years of flute playing and experience with musical theory. Neither of these subjects are in my wheelhouse. On the first read, the most interesting points concerned his visual analysis of bone flutes from Puebloan sites. Among other suppositions, he suggests that the sound window shape can determine how the instrument was played (figure 3). Round holes could serve as the embouchure of a transverse flute or as tone holes of for an end blown flute. Notched holes could be played from either end. Triangle or square holes suggest ducted flutes. (Payne 1991)

Figure 3. Examples of sound windows with arrows to indicate wind direction and cross-section showing sound chamber. a: Transverse flute with plug. b: End blown flute, with wind blowing across the open end. c: Notched, making a hole with fipple edges to allow play from either end (my best guess). d: D-shaped window of a ducted flute with interior duct to direct air flow.

In discussing the bird bone flutes of Pecos, Payne notes that the site was occupied until the nineteenth century and that bone flutes from later contexts show evidence of European influence. Frustratingly, the claim isn’t supported with examples. Further, he mentions an article by Charles Peabody, the first director of the Peabody, wherein a flute from Pecos produced musical tones equivalent to a tabor pipe, again suggesting Western influence (Payne 1991).

The article by Charles Peabody, a talented flautist and ethnomusicologist, among other things, was written in 1917. In it, he describes asking Alfred Kidder for permission to experiment with a bone flute that was recovered while visiting Pecos during the 1916 season’s excavations. Permissions secured, those experimentations included inserting a plug of modeling clay in the proximal end of the flute. Prior to the insertion, the instrument played tones that were “excessively shrill.” After the insertion, the flute played several tones within the C sharp scale. A figure of the flute is included in Charles Peabody’s article (Peabody 1917).

When a comparison is made of the flute in Peabody’s article and the flute in question, it is clear that they are indeed one-and-the-same. The most likely scenario is that Charles Peabody acquired the flute at Pecos before it was cataloged. Eventually, it made its way back to the Peabody and was returned to the collection. By the time it was found with other materials from Pecos, all institutional knowledge of the item had been lost. Fortunately in this case, there was some record of its history.

With the story of the flute’s provenience resolved, there seems, to me, to be other questions left unanswered. These are the references to Western influence in both the musical tones and the flutes themselves suggested by Richard Payne and to a lesser degree, Charles Peabody. I’ll address those in a follow up blog.

References:

Conlon, Paula

2002       The Native American Flute: Convergence and Collaboration as Exemplified by R. Carlos Nakai. The World of Music 44(1): 61-7

Payne, Richard W.

                1991       Bone Flutesof the Anasazi. Kiva 56(2): 165-177

Peabody, Charles

                1917       A Prehistoric Wind-Instrument from Pecos. American Anthropologist n.s 19: 30-33

Work Duty: a Sign of Nearly Normal

Contributed by John Bergman-McCool

The arrival of COVID in March 2020 brought abrupt changes to the Peabody. Suddenly, we were working from home. We also canceled our volunteer program, and stopped hosting researchers, classes and work duty students. Gradually, a few staff started coming back in to the museum to continue (and finish!) the important collections inventory and rehousing project. To keep safe, we each had a floor to ourselves.

The library became my new workspace while we de-densified. It was a great location to inventory the very full drawers of material from the Mandan. Windows and a giant table, who could ask for anything more?

Vaccinations meant the return of our remaining staff and last summer we had volunteers and researchers back. This year’s fall term saw a return to nearly normal with classes and work duty students returning.

The return of students has been the single greatest change since we pulled back at the start of the pandemic. The building is periodically alive with the sounds of students again. Apparently, a place where students could gather and learn about archaeology were two of the conditions purportedly laid out by Robert S. Peabody when he founded the institution (source: Glory, Trouble, and Renaissance at the Robert S. Peabody Museum of Archaeology, page 4). In addition to our regular collections work, there is much more bustle as we pull items for classes and prepare for work duty students.

This year we have welcomed 16 work duty students back into the fold at the Peabody. They are currently engaged in several important projects, including revisiting items from the earliest stage of the inventory project. The students are adding a greater degree of detail to their descriptions, documenting additional notes and rehousing items per our updated standards. Others are learning how to write condition reports for the items pulled from collections for class lessons. Finally, work duty students have uploaded to our database nearly two-thousand slides from Copeland Marks’s travels that were digitized during our work-from-home phase.

Example of two drawers (left) before rehousing, (right) after rehousing.

We appreciate the help we receive from Andover students and are grateful that circumstances and planning have allowed them to return to us at the Peabody.

Work Duty students preparing to throw atlatl for a bit of end of term stress relief.

New Art at the Peabody

Contributed by John Bergman-McCool

Johnny Yates, lalá, 2021

We are pleased to announce that the Peabody has installed an interactive artwork by Jonny Yates (aka Jonny White Bull).  Jonny is a member of the Standing Rock Sioux Tribe and lives in McLaughlin, South Dakota. He is a talented jewelry maker, stylist, and chef, known for his own version of burger dogs, nachos with homemade chips, and other delicacies.

The piece, titled lalá, or grandfather, in the Lakota language, is a reference to Jonny’s ancestor Sitting Bull, who is depicted here. Jonny is the consummate “maker,” who loves creating carved and painted bone jewelry, drawings, and three-dimensional pieces made from cardboard, milk jugs, and other found materials.

Jonny invites everyone to spin his kinetic artwork and reflect on your own ancestors. You can find lalá in the Hornblower Gallery on the first floor of the Peabody.

CONTEMPORARY ART AT THE PEABODY

Jonny Yate’s piece joins a small but growing collection of contemporary Native art at the Peabody. When possible, the Peabody has purchased and commissioned artwork from Native artists with the support of donors and members of the Peabody Advisory Community. Artists with work in the collection include Dominique Toya, Maxine Toya, Bessie Yepa, Jeremy Frey, and Jason Garcia. These artists highlight some of the unique relationships that have developed between the Peabody and Native artists over the years. As an example, the Andover community has been fortunate to have several visits by Pueblo potters Dominique, Maxine, and Mia Toya over the years. During these visits, the Toyas share traditional pottery methods with students in Thayer Zaeder’s ceramics classes. They are very talented artists and quite passionate educators. You can read more about their most recent visit here.

Contemporary art in the Peabody Collection. From upper left: Jason Garcia, Jeremy Frey, Maxine Toya, Dominique Toya, and Bessie Yepa.

THE INSTALL

Hanging Jonny’s kinetic artwork presented a unique challenge; how could we make the piece available for a hands-on experience for students and visitors while keeping it safely installed. Research institutions, such as the Peabody, do not normally put collections on display, so we carefully considered our options. We chose to use cleats to secure the piece to the wall and a makeshift security clip to keep the piece from sliding out of the cleat. In place of a detailed narrative of the installation process, here are a series of photos of how we chose to approach the process. We hope you come by sometime and experience it for yourself.

lalá arrived hanging in a travel case
Access to the back was necessary for adding hanging hardware. The piece was safely removed before cutting a hole in the travel case, it was then re-hung.
Cleats were installed on the back top and bottom.
A receiving cleat was anchored to the drywall to secure the artwork.
Security clip (screw and washer) ensures that the artwork won’t slip off the receiving cleat while being spun.

Rehousing a vessel with salt damage

Contributed by John Bergman-McCool

In January, the HVAC system in one of our collection storage areas malfunctioned. Repair work required that the system was turned off for several days. During this time, we monitored the objects for any changes. One vessel caught our eye.

Thanks to Marla’s experience with the collection, she noticed that previously documented spalling due to salt efflorescence was likely developing further (see figure). A quick look at older photographs confirmed that the damage had indeed progressed. The vessel was stored on open shelving and an inspection of the area around the object determined that no fragments had fallen completely off. We decided to rehouse the vessel in a box to buffer it against changes in environment during the current or future failure of the HVAC system.

Figure 1. Rehoused vessel in open box

Since I’ve encountered salt efflorescence a few times, I thought I’d add a bit more information. Porous materials, like bone, ceramic and stone, can absorb salt from various sources. Once inside, salts can be dissolved by moisture in the air through a process called deliquescence. Eventually, the water evaporates and the salt recrystallizes. In very porous objects, the salt crystals form on the surface. In objects where the surface is less porous than the underlying body, recrystallized salt can generate massive forces than can spall or pit the surface (Source: NPS Conserv O Gram 06/05 page 1). In worst case scenarios objects can disintegrate.

As I mentioned in an earlier blog, salts can enter porous objects through groundwater or seawater in buried or submerged contexts (Source: NPS Conserv O Gram 06/05 page 1). They are a major source of salt in archaeological collections such as ours. In the case of ceramics, food and water stored in objects during their pre-burial use life can also leave salt residues (Source: Minnesota Historical Society Page 2). Salts can be introduced to ceramics during manufacture through additives that modify the clay body and through water (Source: Minnesota Historical Society Page 2, Source: Digital Fire). Even clay itself can be salty. When I lived in Arizona, I can remember hearing a potter discuss that they would check their clay by tasting it to make sure it wasn’t too salty.

After ceramic objects are recovered during excavation, salts can continue to be added in archaeological labs and museums. Hydrochloric acid has been used to remove calcium carbonate, an insoluble salt that adheres to ceramics during burial that impedes analysis. An unintended result of this process creates calcium chloride, a soluble salt, which is absorbed into the ceramic matrix (Source: The International Institute for Conservation of Historic and Artistic Works- Studies in Conservation Page 172, Source: NPS Conserv O Gram 06/05 Page 2). I would be highly doubtful of repairs that were done years ago. Without detailed treatment records, who knows what glues were used and what contaminants they might introduce.

Figure 2. Spalling due to efflorescence

Deliquescence and evaporation of soluble salts can be greatly diminished by keeping the storage environment below 60% relative humidity and by reducing humidity and temperature fluctuations (Source: NPS Conserv O Gram 05/06 Page 3). However, there is a continued danger of efflorescence. Display cases and storage shelving made from wood have the potential to release acetic acids. This volatile organic compound has the potential to interact with soluble salts leading to precipitation even in controlled storage environments (Source: ICOM Committee for Conservation Page 640).

There may not be quick or inexpensive solutions to mitigate efflorescence. Our current plans for renovation of Peabody collections spaces call for the replacement of wood drawers and cabinets, but this is expensive. In regards to removing salt from objects, the traditional method is through a desalination wash or soak, wherein the object is immersed in distilled or deionized water until the salt level is reduced. This is a complicated process and shouldn’t be done without involving a conservator. Desalination risks removing important residues and compounds that can reduce the usefulness of the objects for future analysis and weaken the object (Source: NPS Conserv O Gram 05/06 Page 3).

Here at the Peabody we’ve taken steps to remove salt through dry brushing, environmental controls, and monitoring. In the future, we have plans to improve our storage space so that these issues will no longer be a concern.

Out of the basement and into the basement

Contributed by John Bergman-McCool

RSP to Home
4 months of working in my basement and now, I’m back in the Peabody basement.

After four months of working from home, the Peabody is in its third week of a return to almost normal collections work. The two inventory specialists, Emily and myself, are working alternating weeks at the Peabody in order to continue our inventory work. With one week completed, it feels good to be back working toward our goal of a complete inventory of the collection. While working remotely will be an ongoing reality, I would like to share some of what I have been up to at home thus far.

With everything shutting down in March, Marla was quick to come up with projects that could be completed remotely. Her post in April outlined collections materials that were less sensitive and therefore reasonable to take home. I started with photographing site records from Peru and then moved to digitizing vacuum treatment paperwork related to Integrated Pest Management of the collections. We all contributed to finalizing the digitization of the original ledger books, our institution’s version of accession books. Now we have a searchable document with 75,000 records!

Work from home stuff copy
Everything I’ve worked on from home

My favorite project has been photographing and editing photographic slides held in the collection. They include images documenting past exhibits and openings at the Robert S. Peabody Museum and photographs of the collections. The most interesting slides by far have been of Copeland Marks’s travels in Guatemala and South Korea. Mr. Marks was a textile collector who focused on the traditional clothing of ethnic Maya people living in the Guatemalan highlands. Some of his textiles became part of our collection at the Peabody. He would later write several cookbooks on cuisine covering locales ranging from the Mediterranean to South America. The slides I was working with document his travels in Guatemala spanning the 1960s through the 1980s. The subjects in the photographs cover everyday life, the dramatic volcanic landscape of the highlands and ceremonial life- all of which have been a great escape from the realities of coronavirus lockdown.

00.3.1585 copy
00.3.1585- People of San Pedro La Laguna.

It is anybody’s guess when life will return to normal. For the foreseeable future work at the Peabody will be interspersed with the strange blur of working from home with frustratingly cute interruptions from kids and dirty dishes. Until then I have to thank Marla for keeping us safely working from home during these crazy times.

lunch for 2
Oh yeah, I can’t forget my other work from home duty- silly lunches for the kids.

Happy Holidays from the Peabody!

Contributed by John Bergman-McCool and Marla Taylor

In November Marla and Ryan approached me (John) with an idea for an illustrated holiday card. They wanted a family portrait-style image of the Peabody staff. I jumped on the opportunity thinking that hand-drawn portraits would be a unique twist on the usual offering. However, I didn’t realize how difficult the likenesses would be. After many hours of sketching, digital coloring and editing and much consternation, we have a card! Emma worked her magic to make a very polished finished product. It was a fun challenge, though my kids think I look super weird.

John
Me…sort of

From my perspective (Marla), holidays at the Peabody are not complete without a meal to celebrate our volunteers.  These wonderful people give several hours of their time, each week, to help us out.  They do everything from label file folders to inventory drawers to inspect artifacts for evidence of pests.  Our amazing volunteers – Quinn, Susan, and Richard – are a gift we get to share all year round.  (and the spread of homemade food isn’t too shabby either!)

potluck
I was too busy eating to take a picture of our actual spread. Enjoy this clipart!

Wild Ride No More

Contributed by John Bergman-McCool

Cups and Coaster
The collections environment before and after rehousing in archival boxes

Back in March I wrote a blog post summarizing efforts to rid collections objects of mold and salt uncovered during inventory and rehousing. We identified and isolated affected objects and cleaned them by dry brushing and vacuuming. The cleaned objects were rehoused in archival boxes that included a sachet of silica gel. The purpose of the gel is to reduce relative humidity (RH), thereby robbing mold and salt of the environmental conditions necessary for their growth. To better understand what the environment is like inside the boxes, we are monitoring their temperature and relative humidity with two data loggers. One is placed inside a box without silica gel and one is placed inside a box with silica gel. These conditions will be compared against a data logger that is recording general conditions in the basement not far from where these test boxes are located. We will be watching these data loggers over the coming year, but we already have some interesting results.

Temp and RH graph for John August 2019
Environmental Stats for April

First, the boxes are working well as a buffer against relative humidity cycles. The graph above shows RH and temperature for the month of April; the basement is shown in red and the boxes with and without silica are blue and yellow, respectively. In April the RH in the basement was quite volatile. However, the RH inside the boxes is remarkably tranquil in comparison. The boxes are exhibiting small daily shifts of 1 or 2%, which is acceptable. Keeping RH from shifting dramatically is an important factor in collections care. Organic materials such as basketry, bone, and wood are hygroscopic, meaning that they can absorb and release moisture in the air. Rapid and large changes in RH can cause organic materials to swell and contract leading to damage such as cracking or delamination. It is best to keep collections from experiencing RH shifts exceeding 10% over a given month and on that count the boxes are doing a great job. As they are found, the most sensitive organic collections are being moved to another part of the museum that has a better environment.

Layerd Storage
Layered Storage

The National Park Service recommends creating a layered approach to collections storage. Every enclosure within museum storage can act as an environmental buffer. The first enclosure is the building itself. It may seem pretty obvious, but keeping collections inside a building greatly reduces the effects of environmental factors. The same is true of every subsequent layer of enclosed storage. Here at the Peabody Institute we have wooden storage bays that, when closed, serve as another layer. The archival boxes act as a final layer.

 

Interestingly, the basement seems to be effective at buffering daily temperature cycles. The temperature in the basement has been hovering around 70 between February and June leaving little for the boxes to mediate.

Sachet
Silica Gel Sachets

The second finding of note is that the sachets of silica gel were spent faster than anticipated. As mentioned above sachets of silica gel were placed in the boxes with cleaned objects. The gel, in solid pebble-like form, starts out orange and as it absorbs water it changes to a deep blue. The expectation was that the gel would keep the RH at a reduced and steady level. The graph above shows that the silica gel was keeping relative humidity lower than that of the box without gel, but it is only a matter of a few percentage points. Most likely the boxes are not well enough sealed for the silica gel to more significantly moderate RH levels. The silica was active from mid-February until mid-April (see star on graph) when RH graphs inside both boxes started to match almost perfectly. A visual inspection in June indicated that the gel was spent. We replaced the silica in mid-June and it was spent within two weeks given the higher RH levels generally in the basement.

 

Our data shows that the boxes are acting as a significant buffer against potentially damaging cycles of increasing and decreasing RH levels. For now, we are forgoing replacing spent silica gel. Later in the fall we’ll see how the archival boxes work with our dehumidifiers at keeping mold and salt inducing RH at bay.

Uninvited Guests

Contributed by John Bergman-McCool

Mold_Salt 1
Meet Mold and Salt

In early February we wrapped up inventorying and rehousing collections that originated in Missouri. The work was followed by two weeks of cleaning, and as a result we’ve completed one of the regions held in the collection. So you may be wondering what we were cleaning. During the inventory, we encountered bone and antler objects covered with salt crystals and patchy dormant mold. The objects were cleaned before they were stored inside their new boxes to remove salt and minimize the risk of mold spreading to unaffected objects.

Where did the mold and salt come from and why are they a problem?

Mold spores are found everywhere in the environment. When the humidity is high, those spores germinate resulting in mold. Because it is a living organism, mold is classified in the museum world as an agent of biological deterioration. It eats organic matter, in this case the dust resting on the outer surface of bone or the bone itself, and secretes waste that can stain or damage the surface that it is growing on. Mold can appear to be dormant, but when the conditions are right mold will generate spores that are easily borne on the wind, allowing it to spread quickly.

Mold_Salt 2
Agents of deterioration

Salts on the other hand are considered chemical agents of deterioration. They are brought into museum collections on the objects themselves.  Dissolved salts present in groundwater can be absorbed by porous objects, such as bone, while they are buried underground. After the water evaporates the salts are left behind. Excessively humid conditions can dissolve soluble salts, allowing them to move through porous objects. When they arrive at the surface they form crystals. If the crystals form below the surface they can exert enough force to cause damaging cracks and spalling.

Mold and salt thrive in damp environments where the Relative Humidity (RH) is above 65%. The institute’s storage area is located in the basement, which does not have a controlled climate, so mold and salt are an unfortunate reality. Currently, the RH in the basement is somewhere below 15% (15% is as low as our monitoring equipment can read). RH levels this low shouldn’t support active mold and salt growth, so what we found is inactive, but it is hard to say when and for how long the growth of mold and salt was last active.

At the Peabody we are committed to maintaining the longevity of this very important research collection and salt and mold pose a risk to its scientific viability. Damage to the surface of artifacts caused by mold and salt can negatively impact the research value of the collection.

How do we prevent mold and salt?

While we don’t have an HVAC system maintaining the environment in basement storage, we have adopted a few practices that will mitigate and prevent future growth of mold and salt. First, we use dehumidifiers during times of high humidity that typically arise during the summer. Second, we are moving the artifacts currently stored in open drawers and rehousing them in closed archival boxes. The enclosed space of a box helps create a buffer that protects the contents from rapid shifts in RH that lead to mold and salt growth. The boxes will also keep future mold growth from spreading; something that was not possible with open-drawer storage.

Mold_Salt 3
Vacuum defeats Mold and Salt

In addition to the rehousing, we have implemented a cleaning program. When mold and salt are identified we isolate the effected object to keep spores from spreading. We clean the affected artifacts with a dry brush and vacuum. After we clean we use sachets of silica gel to absorb excess moisture, thereby providing another buffer against cycles of RH increases and decreases. In six months we’ll check on the status of the bone to see if the mold and salt are staying away.

A New Face in the Basement

Contributed by John Bergman-McCool

Hi there! My name is John and I am the new Inventory Specialist at the Robert S. Peabody Institute. As Inventory Specialist my primary task is to work on the ongoing inventory and rehousing project. The project’s goals are to fully understand the collections that are held at the Institute and move them from their old wooden drawers into archival boxes. Armed with the more precise knowledge of what is in the Peabody, the institute can ensure their continued care and share them with students and the public for years to come.

This position is a dream job for me. It brings together my interest in archaeology, museums and collections care, and who doesn’t love spending time underground!

John inside a pit during excavations
Yep, this is me in a bell pit during an excavation in Arizona!

Before moving to Massachusetts in 2013, I worked for almost a decade as an archaeologist in the Pacific Northwest and Arizona. After relocating to New England I enrolled in the MFA program at Tufts and the School of the Museum of Fine Arts. During my time as a graduate student I found that I kept coming back to archaeology and the history of museum collections as a subject for my artwork.

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Artwork from my thesis project

While I was in graduate school I also pursued a certificate in Museum Studies. I gravitated towards collections care and since graduating I’ve worked in collections at the Fitchburg Art Museum and Historic New England. ­

In a round-about way I’ve come back to archaeology, though it’s been following me for the past 5 years. During my time here I’ve been inventorying objects from Missouri. There have been some surprising finds, which has been great. You never know what you’re going to find here at the Peabody.