Have you ever wondered what it would be like to work in a museum? The Peabody, like many museums, has a small force of volunteers who dedicate a few hours each week to helping our staff further our work. We are currently looking to expand this group of volunteers.
Our volunteers have assisted us with a huge number of projects. We currently have one volunteer who works with our textile collection. In a museum setting, it is very important to protect artifacts from pests that can occasionally work their way into the building. Our textile artifacts are particularly susceptible to the damage from carpet beetle and clothes moth larvae. An infestation of these pests can completely destroy a textile collection without proper intervention and pest management. In order to stay on top of any potential pest problems, one of our volunteers systematically goes through our textiles and inspects them for evidence of damage, insect excrement, and live specimens. This involves vacuuming the textiles, inspecting them, and putting them through a freezing process designed to kill living pests. Once this two week process is completed, the textiles are removed from the freezer, isolated, and then inspected again for any signs of life. Once we are satisfied that pests are not present, the objects are returned to the collections storage space. Our volunteer has done an excellent job with this, and has made significant process on this project.
Our other current volunteer is a P.A. alumnus who works on a wide variety of projects. One of the most important projects is our complete inventory of the collection. We hope to renovate the Peabody in the next few years and before we do that, we need to have a completed inventory of our collections. This involves inventory of our storage drawers and recording information about collections, including objects present, count, geographic origin, and current storage location. Volunteers can help with this most important project.
In addition to helping out with the inventory, volunteers help out as needed across the Peabody. Other projects include organizing portions of the archives for researchers, pulling out and putting away objects for classes, creating labels for our artifact boxes, and transcribing catalog cards into a digital system. There is never a shortage of work to be done at the Peabody!
If this sounds like an opportunity that you would be interested in, feel free to contact me with for more information at firstname.lastname@example.org. I would be glad to speak to anyone about potentially volunteering for us!
This skeleton is from a site near Glorieta, New Mexico – just southeast of Santa Fe – and collected by Alfred Kidder during his work at Pecos Pueblo.
As discussed in a previous blog, The Macaw Factor, the presence of macaws in the southwest is certainly note-worthy. These birds have a natural habitat approximately 1000 miles to the south and were clearly transported to the region as status symbols. They may have been kept for their feathers or displayed as a sign of wealth and connections.
As we continue to move through the collection, who knows what we will find next!
In my last blog I discussed soil analysis and its importance in dating and understanding a site. Another form of analysis used in the Tehuacán Archaeological-Botanical Project by Richard “Scotty” MacNeish was a process called radiocarbon dating, a technique developed by University of Chicago physicist Willard Libby. Carbon samples were collected during excavation and sent for carbon dating to be used for the Tehuacán Chronology Project.
There are two techniques for dating in archaeological sites: relative and absolute dating. Relative dating, in a stratigraphic context, is the idea that objects closer to the surface are more recent in time relative to objects found deeper in the ground. This relates to the law of superposition, which in its plainest form, states soil layers in undisturbed sequences will have the oldest materials at the bottom of the sequence and the newest material closer to the surface. Although this form of dating can work well in certain cases, it does not work for all.
Many sites include soil layers that have been disturbed and this
can happen several ways. Natural disasters, such as floods, can erase top
layers of sites. Rodents can move around layers in a site as they burrow
underground, sometimes moving items from one context to another. Even current
human activity can change the stratigraphy of a site through construction, post
holes, and pits.
This takes us to our second dating technique. Absolute dating
represents the absolute age of a sample before the present. Examples of objects
that can be used to find absolute dates are historical documents and calendars.
However, when working in an archaeological site without documents, it is hard
to determine an absolute date. If a site has organic material present,
radiocarbon dating can be used to determine an absolute date. Radiocarbon
dating is a universal dating technique that is used around the world and can be
used to date materials ranging from about 400 to 50,000 years old. Radiocarbon
dating may even work on very recent materials.
Organisms such as plants and animals all contain radiocarbon (14C). When these organisms die, they stop exchanging
carbon with the environment. When this occurs, they begin to lose amounts of 14C overtime through a process called radioactive decay. The half-life of 14C is about 5,730
years. Radiocarbon dating measures the amount of stable and unstable carbon in
a sample to determine its absolute date. As a result, the older the organic
material, the less 14C it has relative to stable versions of the
The carbon samples recovered from the Tehuacán Valley were
collected specifically with this in mind. Many of these samples had labels or
notes stating that some of each sample was sent to labs for radiocarbon
testing. The carbon samples are organic material and their properties of
radiocarbon were used to determine the age of the material, which in turn, helped
date each site.
The following sites are represented in some of the jars of carbon samples I catalogued from the Tehuacán Archaeological-Botanical Project.
Site Number Site Name Radiocarbon years
Tc 35 El Riego 6800 to 5000 B.C.
Tc 50 Coxcatlan Cave 5000 to 3400 B.C.
Tc 307 Abejas 3400 to 2300 B.C.
Tc 272 Purron Cave 2300 to 1500 B.C.
Ts 204 Ajalpan 1500 to 800 B.C.
These results were published in Volume Four of MacNeish’s Prehistory of the Tehuacan Valley: Chronology and Irrigation and can be found on Page 5. MacNeish and Tehuacán Chronology Project director, Frederick Johnson, selected carbon samples to be sent for testing, which resulted in the determination of 218 radiocarbon dates. Johnson played a prominent role in radiocarbon dating, serving as the chair of the Committee on Radioactive Carbon 14 set up by the American Anthropological Association. This project not only produced a chronology for the Tehuacán sequence of excavated sites, but later contributed (along with 400 additional radiocarbon dates) to the chronology for all of Mesoamerica. The dates, however, were made within the first two decades of radiocarbon dating and lack the accuracy and precision now available with newer techniques, especially with the older dates.
To read more about the Tehuacán Archaeological-Botanical Project
and the Tehuacán Chronology Project visit Internet
Libby, Willard F. Radiocarbon
Dating, 2nd ed., University of Chicago Press, Chicago, IL, 1955.
MacNeish, Richard S. et al., The Prehistory of the Tehuacan Valley: Chronology and Irrigation.
Vol. 4. University of Texas Press, Austin, TX, 1972. Print.
In April the University Press of Florida published Iconography and Wetsite Archaeology of Florida’s Watery Realms, my new book, co-edited with Oxford’s Joanna Ostapkowicz. Watery Realms highlights current research on sites and artifacts preserved in anaerobic environments throughout Florida. This blog reproduces some of the book’s first chapter, which recounts the origins of the volume and some of the exciting research presented.
The book grew out of the symposium The Archaeology, Art, and Iconography of Florida’s Watery Landscapes that we organized at the 81st annual meeting of the Society for American Archaeology (SAA) in Orlando, Florida, not terribly far from some of the amazing sites being discussed. By coincidence, the icon of the 2016 SAA meeting was the Hontoon/Thursby owl, which was the focus of our conference presentation and recent study. This made the venue doubly relevant in highlighting the importance of Florida wetland archaeology. As the session grew into the Watery Realms book, it expanded to include other contributors and has inspired new collaborations. A generous grant from the Toomey Foundation for the Natural Sciences helped underwrite the symposium and ensure that presenters from graduate programs, government agencies, cultural resource management firms, universities, and museums were able to attend. William Marquardt, a co-presenter on the wetsite resources of the Pineland site with Karen Jo Walker, volunteered to write a chapter for the book on the interesting corpus of wooden anthropomorphic figurines from southern Florida. Rick Schulting, who was involved in the strontium isotope analysis of the Hontoon/Thursby carvings in our study, linked with Julia Duggins over ways to test her ideas about Florida canoes and watersheds, a project that secured a Wenner-Gren Foundation grant. Plans for future collaborations on the anthropomorphic figurines and Key Marco material are also under way. Our discussants Jim Knight and Lee Newsom pointed out many of the ways the presenters could connect their work and explore Florida’s wetsite art.
The idea for the symposium emerged through a rather circuitous route. It began at the SAA’s 78th annual meeting in Hawaii, where I first meet Joanna Ostapkowicz. We were participants in a general session called By Design: Iconography in Social and Cosmological Negotiations, which included an interesting array of papers on everything from Dorset art to Egyptian textiles. Our papers contributed to enlarging the geographical scope to Florida (Wheeler: “Thinking about Animals in Ancient Florida”) and the Caribbean (Ostapkowicz: “The Sculptural Legacy of the Jamaican Taino”). Before and after the session we talked about how many iconographic wood carvings were known from Florida, from Key Marco to Fort Center and everything in between. Joanna suggested that the techniques she had been using with Caribbean wood carvings might have interesting applications in Florida. Many of the Caribbean pieces had traces of pigments and adhesives that were modified over relatively long periods of time. Some of this could be understood with a combination of microscopic examination and AMS dating. She also suggested that it might be possible to use isotopic analysis to understand the origin of a piece and how it could have been moved during its use life. In responding to slides in Ryan’s presentation, Joanna said something that was intriguing, namely that none of the carvings bore much similarity to Caribbean pieces, the potential connections between these geographically close areas remaining a hotly debated topic in some circles of Florida archaeology. We agreed to collaborate and decided that the Hontoon/Thursby and Tomoka carvings would be a good pilot study. We secured a National Environment Research Council (UK) grant to undertake AMS radiocarbon dating on the four sculptures. The results of that collaboration are explored in Chapter 9 of Watery Realms and in our recent article in the Journal of Archaeological Science: Reports. During our field trip to visit the Hontoon/Thursby and Tomoka carvings, we linked with many colleagues who are doing research on Florida’s wetsites, both collections-based study and reanalysis, and learned of new discoveries. After canvassing people about their work and interest, we decided to organize the SAA symposium.
That is not really the whole story, however, as there was another person in the audience of our symposium who deserves a lot of credit for modern studies of Florida’s wetsites, wooden artifacts, and iconography. Nearly all of the presenters that day mentioned Barbara Purdy, professor emerita of the University of Florida. She led a statewide investigation of dugout canoe finds from the 1970s until her retirement in 1992, maintaining extensive files and documentation on hundreds of canoes. She also led excavations at Hontoon Island in the 1980s to probe the wetsite deposits there, followed by a project at Lake Monroe, where I had my first taste of wetsite archaeology as a graduate student in the 1990s. In fact, I tracked down several canoes with Purdy and fellow grad student Ray McGee in the early 1990s; this work prefigured my involvement in the Lake Pithlachocco canoe site some ten years later. In 1991, Purdy published a compendium of Florida’s wetsites in Art and Archaeology of Florida’s Wetlands, building on her statewide survey of wetsites in 1981. That book was followed by Indian Art of Ancient Florida, a survey of Florida’s American Indian art with photographer and curator Roy Craven. It is most appropriate that the Watery Realms book is dedicated to Barbara Purdy, a pioneer of Florida’s wetsite archaeology and studies of wooden artifacts and carvings. Purdy encouraged an appreciation of canoes as fascinating artifacts in their own right that embody information about past lifeways and deserve care and study. Purdy organized and hosted several international wetsite conferences that resulted in important proceedings on the subject and created a community of scholars dedicated to the documentation and preservations of wetsite artifacts. She has continued to advocate for more recognition for Florida wetsites. Archaeologists still avoid damp and low areas during surveys and seldom think about intentional prospecting for these important sites. That is changing, however, largely due to her work, which introduced many of us as students and professionals to the hidden world of wetsite archaeology.
The rest of Chapter 1 introduces the environment of Florida and gives a brief overview of the other eight chapters, as well as some thoughts about major themes covered in the book and prevalent in wetsite archaeology. Copies are available from Amazon.com and directly from the University of Press of Florida.
My name is Ryan Collins, and I am an Archaeological Anthropologist specializing in Ancient Maya Culture. I recently earned a Ph.D. in Anthropology from Brandeis University where I also instruct courses (as well as at Northeastern University and Lesley Art + Design) in Archaeology, Anthropology, Latin America, and Material Culture Studies.
I am also fortunate enough to have two roles with the Robert S. Peabody Institute of Archaeology. First, I am the Transcription Project Associate, working through the museum’s original bound ledgers to create a digital inventory. While there are several subjects of interest that I want to explore from the Ledger Transcription Project (including the stories of somewhat mysterious artifacts), the subject of this post will focus on my role as the Lead Archaeologist with Mansion House Excavations happening on Phillips Academy’s Campus during the Summer Session with the Lower School Institute. The Mansion House excavations happen in collaboration with the Robert S. Peabody Institute of Archaeology which houses recovered artifacts as well as materials that once belonged in the late 18th-century building.
The Mansion House at Phillips Academy Andover is a site of significant historical importance in the local community. Built during the Revolutionary War in 1782 (though fully completed in 1785) it was home to Phillips Academy Andover’s founder, Judge Samuel “Esquire” Phillips Jr., and his family until 1812. During this time Judge Phillips, his wife Phoebe Phillips, and their family were known to cultivate a warm and inviting atmosphere to the students of the academy while also hosting notable political figures of the day like President George Washington.
With the decline of Phoebe Phillips’ health in 1812, the Trustees of Phillips Academy purchased Mansion House converting it into an Inn and Tavern. As an Inn and Tavern, Mansion House became a central meeting place for students and faculty of the academy as well as for residents in Andover. Over the years Mansion House hosted notable guests including Emerson, Webster, President Andrew Jackson, and Mark Twain among many others. Although, when looking through the guest ledger on the date of his stay, Mark Twain’s signature is absent having mysteriously been cut out.
The history of Mansion House and its guests is enough to capture the attention of archaeologists. However, beneath Mansion House’s rich past is an enduring mystery – who burned it down? On the very early morning of November 29th, 1887, around 2:00 am the tenants were awoken by thick smoke coming from a fire in the rear base of the house near a pile of woodchips. A second fire was discovered shortly after in a third-floor room at the front of the house. Despite the best efforts of the local fire brigade and a galvanized town, Mansion House could not be saved. As chronicled by the Andover Townsman on December 2nd, 1887, Mansion House did not collapse, but it “slowly melted” into its foundations.
Most sites and buildings that archaeologists explore are little more than skeletons of their former selves. This reality puts limits on the archaeological record (often refuse in this context) and on the questions that archaeologists can ask about a site to broad notions of process or change over time. With Mansion House, a question of this variety would be: How did Mansion House change over time? What traditions are evident in the material remains of the site? However, because Mansion House burned into its foundations, we have access to an event, a specific moment in time. In this way, the materials students recover from Mansion House will help then share different informed stories about the site, its residents, and life in the 18th and 19th centuries. (IMAGE 4)
In 2018, our excavations confirmed the location of Mansion House by finding one of its (at least) 6 chimneys and the remains of an iron furnace. This finding not only establishes a more precise understanding of where Mansion House’s foundations are currently situated but it allows us to explore the material remains that have sat untouched for 132 years. With luck, this year’s investigations will allow us to understand even more about life in Mansion House during its final days. While the mysteries around the long-ago fire are unlikely to be solved, more insight will undoubtedly be learned about Phillips Academy and the local Andover community. Excavations at Mansion House will reopen in July of 2019.
This time of year usually sees a blog post about our attendance at the annual meetings of the Society for American Archaeology (SAA). The meetings are held in late March or April and attract thousands of archaeologists from around the world who share their research, connect with old friends, buy books in the exhibit hall, and generally revel in our discipline. The Peabody and Phillips Academy have a long history with the SAA and its annual meeting. The first ever annual meeting of the Society was held at Phillips Academy in December 1935. Doug Byers, the long-time director of the Peabody, served as the editor of American Antiquity, the Society’s flagship publication. Richard “Scotty” MacNeish was president of SAA.
Peabody personnel have continued to be involved with SAA. Staff members and members of the Peabody Advisory Committee regularly present papers and posters in the annual meeting sessions. Since 2017 we have had a booth in the annual meeting’s exhibit hall to promote the Linda S. Cordell Memorial Research Award, our book Glory, Trouble, and Renaissance at the Robert S. Peabody Museum of Archaeology, the Journal of Archaeology & Education, and generally network with folks in attendance. This year’s meeting was much the same, with lots of comradery with old and new friends, some great New Mexican cuisine, sightseeing at Petroglyph National Monument, and a visit to Albuquerque’s Red Planet Comics, a Native American-owned comic book store.
The difference this year, however, was that our discipline and the Society for American Archaeology have run headlong into issues of sexual harassment and discrimination that have garnered headlines everywhere from the film industry to tech and science sectors, often under the umbrella of #MeToo. These issues have been prevalent in archaeology for decades, and two of the papers in the session that I participated in, Sins of Our Ancestors (and of Ourselves), highlighted the contributions of women in museums and archaeology, and how their voices have often been excluded, their work co-opted, or their names simply excised or omitted from the record.
Shortly before the Society’s annual meeting this year news circulated about a Title IX investigation of a prominent archaeologist at the University of Alaska Anchorage. According to news stories published at the end of March 2019, the Title IX investigation into sexual discrimination and sexual harassment found accusations from nine women all credible. The professor was denied emeritus status, and students and faculty were advised to alert authorities if the professor was encountered on campus. This professor apparently registered for the SAA annual meeting on-site. Not long after this, at least three survivors encountered him at the conference and reported his presence to the meeting organizers. Michael Balter, a journalist who has reported on #MeToo in science and who was at the conference for a session on this topic, also reported the individual’s presence and ultimately escorted the professor out of the meetings. He, however, returned later.
While the above is troubling, it’s only the beginning of the story. The current furor in archaeology centers on the Society for American Archaeology’s response to what happened at the meeting. The initial response was sluggish at best and often misguided. Michael Balter, the journalist who ejected the professor, was himself kicked out of the conference by the meeting organizers. Ultimately, over 2,300 people (many SAA members) signed an open letter to the Society that castigates the SAA for its response and demands action.
Apologies to the survivors were late in coming and there has been a general disregard for how this event has impacted all survivors of harassment and abuse who were at the meeting. Social media posts by the Society have blamed others or presented distorted timelines. It’s left many of us wondering how we can encourage the next generation of archaeologists to attend these meetings if they aren’t safe spaces, let alone continue our own support for an organization that is willing to tolerate sexual harassment and all its attendant hurt, trauma, and pain. At least three of the survivors have gone public with their experiences at the conference, including their interactions with SAA professional staff and leadership. Their posts on social media continue to raise concerns.
The SAA’s new president, Joe Watkins, issued an apology via a video message and letter on April 18. Comments on social media indicate that the apology was well received by some, but not all. Watkins, in his letter to SAA members, promises that the Society “will create a body to examine the short-comings in our sexual harassment policy of 2015 and the anti-harassment policy of 2018” and “do our best to ensure that this does not happen again.” He does, however, acknowledge that the recommendations of task forces have often been ignored by SAA leadership in the past.
My latest work for the Peabody Inventory and Rehousing Project has led me to Tehuacán, where I have been cataloguing glass jars that contain soil samples. These jars are a part of the Tehuacán Archaeological-Botanical Project by Richard “Scotty” MacNeish during the early 1960s. The samples were collected for testing and analysis purposes from the project area. When archaeologists excavate a site, they dig through soil layers formed by the activities of past people. What archaeologists recover from these layers provides clues about what happened at that site from features or artifacts. However, the actual soil is another very important clue for archaeologists, as it can help date sites and tell a lot about the environment of the site during the time the soil layers were formed.
Giving an accurate description of soils help archaeologists better understand what happened in the past at a site. The color and texture of soil can reveal the age of an archaeological site, as well as how the site was used. For example, a circular stain in the soil may reveal a post-hole deposit, indicating that there was once a wooden post that had decayed, leaving a soil discoloration in the ground. Depending on the site, these post-holes could represent a structure or palisade. In addition, studying soil fertility can help archaeologists understand ancient agricultural systems.
Archaeologists use the Munsell Color Chart to help them describe the colors of the soil layers in a standardized way. This system was developed by Albert H. Munsell at what is now MassArt in 1905. Archaeologists compare the soil color in their excavation units to the color chips of the Munsell Chart – similar to the color squares found in hardware stores for paint. Where a color may be brown to one person, it may be gray to another – so it is important that archaeologists use this chart so they can standardize their descriptions.
To describe soil textures, archaeologists and geomorphologists use a soil triangle to help them determine what type of soil they are examining in the field. There are three types of soil components: sand, silt, and clay. Most soils have a combination of these three components and each of these components vary in sizes – sand particles being the largest and clay particles being the smallest. Similar to how the Munsell Color Chart describes soil color the same way, the soil triangle helps archaeologists describe soil texture consistently.
Another way archaeologists analyze their site is through soil stratigraphy. This is the different types of strata, or layers of soil that archaeologists examine to map out the archaeological site over time. Stratigraphy can be used to determine which soil was associated with human occupation and which layers are sterile, meaning the soil is not associated with human occupation and does not contain any archaeological material. Layers that include artifacts and features represent a place where people lived and worked, as archaeologists can see the objects left behind by human activity. Sterile layers such as subsoil, flood sediment, and bedrock are not as distinct, but provide information on a site’s activity or inactivity.
The jars of soil samples were most likely examined after excavation and retained for further analysis. Presently, these soil samples have been rehoused and cataloguing for each of these jars is complete. To learn more about Richard “Scotty” MacNeish and the Tehuacán Archaeological-Botanical Project, visit the Peabody’s online archival collections. The MacNeish archives are available for research, separated into two collections – the Richard S. MacNeish Papers and the Richard S. MacNeish Records.
Birkeland, Peter W. 1974. Pedology, Weathering, and Geomorphological Research, New York: Oxford University Press.
Limbrey, Susan. 1975. Soil Science and Archaeology. London and New York: Academic Press.
Solecki, R. 1951. Notes on Soil Analysis and Archaeology. American Antiquity,16(3), 254-256.
Eighteen Phillips Academy students traveled across China during spring break 2019 on the inaugural Adventures in Ancient China trip, part of the Learning in the World program. Student travelers visited major archaeological sites, cultural and religious sites, and museums and brought back many memories, as well as some great images! We asked students to submit their favorite shots in four categories: a) landscape or cityscape; b) candid; c) texture, pattern, or contemplative; and d) image that tells a story. We received eleven great submissions. Here are the winners in each category:
Landscape or Cityscape
We loved Abdu’s landscape shot of the Great Wall. We were lucky to have some blue skies like this during our last few days in Beijing, and the color and texture gradations from the greens and browns in the lower half of the image to the blues and purples of the mountains and sky give a great sense of the wall around Mutianyu where we stayed. Oh, we hiked this section of the wall too!
This is a great shot of students and chaperones sharing hot pot in Luoyang after a long train ride from Beijing. Seven of us were pretty hungry and delighted when a restaurant owner stayed open late to serve us hot pot. We love the assortment of food on the table and the steam coming from the pot!
Texture, Pattern, or Contemplative
Emily Ho’s close-up of the Dragon Pavement captures some of the amazing patterns and textures that we encountered in China. The carved marble pavement is part of a staircase in the Forbidden City; it was carved in the Ming Dynasty and re-carved in 1761. We really like the contrast and shadows in Emily’s shot!
We saw opera performers getting ready in both Xi’an and Chengdu. What we love about Alexander’s image is the silent conversation happening between the performer and the makeup artist!
We had a hard time picking the Adventures in Ancient China photo contest winners, so we added one extra category. This shot of the Summer Palace in Beijing, by Ramphis Medina, combines aspects of the landscape and patterns, textures, contemplative categories. The Summer Palace is considered by UNESCO a masterpiece of Chinese landscape garden design. Longevity Hill and Kunming Lake, both seen here, are major features of the gardens.
Congratulations to our contest winners and many thanks to everyone who submitted a photo! It was very hard to choose!!!!
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.
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.
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.