At The Lab, Challenging History
The writing of an accurate timeline is one of the more challenging tasks faced by the preservation specialists working on the Cloverfields house.
The house has undergone at least seven significant transformations since it was built, and it is sometimes hard to identify which specific changes resulted from each renovation. A historian may recognize a door as definitely belonging to a certain period, and therefore assume that the structure surrounding the door, made of the same material as the door, and appearing equally corroded, belongs to that period too. The scientific dating of the wood of the frame surrounding the door, however, may tell a different story. The door, for example, may have been added a few decades after the structure around it was built.
When the Cloverfields Preservation Foundation began its research in January 2018, the consensus among the few architectural historians who had written on the house was that it was built sometime in the 1730s (Swann 144, Rideout 83, Graham “Timber Framing” 229, Graham “Interior Finishes” 325, 339). Our team had no reason to doubt this dating until the science of dendrochronology questioned it, pinpointing 1705 as the year of original construction.
The Cloverfields Preservation Foundation dedicated a newsletter titled “Rewriting the Timeline” to this discovery. You can refer to it here. In the newsletter, dendrochronologist Michael Worthington shows us how he takes approximately 60 small samples of wood from different sections of the house. He also tells us about how he then takes the samples to the Oxford Tree Ring Laboratory, where he analyzes them. In the video above, Worthington explains to us what happens in the lab.
The samples are first attached to timber boards and sanded so that they can be scanned. The scan allows the dendrochronologist to meticulously record the dimensions of each ring of each sample. He then compares those samples to those of an extensive database of samples and finds the family to which each sample belongs.
As the clip begins, Worthington describes how he prepares the samples:
So, we are back at Cloverfields, we’ve taken the samples. And this is sort of the sample we took the last time we were here. What we’ve done with them; we’ve taken them back into the workshop, we mated them onto timber boards, and then we sanded them so that we could clearly see every ring.
Only then technology is incorporated into the process, in the form of a scanner:
And then, under a very high-power scanner, we scanned that image, we put that back into the computer, and then with a software in the computer, we are going to start measuring the rings. See the ring widths, the rings are in here, we can see the different widths of the rings, and we can very simply, just by clicking the mouse, measure each ring. This produces a set of data, which is unique to that particular sample. Then what we can do, is take that data, and basically the data just looks like a series of numbers. It’s not very complicated. It’s a series of numbers starting from the middle of the tree towards the outside edge of the tree.
Each sample, therefore, becomes a unique set of numbers, and once the numbers of all the samples are combined and organized, they create the “master chronology” of the Cloverfields house:
We then convert that data into a graph, and we compare one graph against another. We do that with every single sample from the building, and then hopefully we’ll end up with what’s called a “master chronology,” which contains all the samples from the building. There were a lot of samples from the building.
The data of Cloverfields’ master chronology is then compared to the data of an East Coast chronology. Or, in other words, the wood samples of the Cloverfields house are then compared to hundreds of other wood samples of the region. The comparison results in a graph which occasionally shows a spike. When we see a spike, it means that the data from one of the samples of the Cloverfields master chronology is similar to the data of a sample from the East Coast chronology. Worthington takes us through the process, step by step:
We average all that data together, and then we take it to another program in which we basically compare it with all the data we have from the area. So, in this program, we are going to run a check-off set of data from the year 1000 through 2010, we are going to match it with chronologies from the East Coast of the USA, and we are going to match with other 900 chronologies. So every time we get a match this graph will mark it, and you can see every time that criteria works we get a mark on the graph, and it keeps going, keeps going; here we go, now we got one spike showing. So, basically every time we got a match, the graph marks it. If we get one spike, which we seem to be getting, we can actually get a date for each of the samples which makes up that master. We’ve taken so far about 60 samples out of the building.
Worthington then shares with us his impressions on Cloverfields:
Usually, when I am in a building, I am on my own, so in this job, I moved around like 30 other people and everybody has their opinion on what they think it is. That’s quite interesting looking at them; you know, people were thinking it was… you know, the date of the building was a good one for me. Everybody is looking, they are looking at this door, “And this door is 1740s, from about 1740s, so the house must be 1740,” and I am looking at things, and think: “oh, you missed that one.” Ha, ha. Which I do quite a lot.
For a researcher, few feelings are more satisfying than proving that previous research was simply not correct.
This month, the team at Applied Archaeology and History Associates have information on botanical remains found at Cloverfields. The careful eye of the archaeologist is able to sift, sort, and identify botanical remains found in the soil of archaeological dig locations. Alexandra Glass and Jeanne Ward explain:
Due to the Chesapeake climate, fluctuations in humidity and temperature often cause organic materials to decompose quickly leaving little for archaeologists to analyze. However, preservation can occur when organic material becomes carbonized. Carbonization of seeds, wood, and plant fragments occur in environments where the temperature is very high, but oxygen is low. Carbonization preserves organic material by maintaining the shape and morphological characteristics of the object while eliminating material destructive micro-organisms feed on.
At Cloverfields, AAHA staff have been working to collect preserved plant remains through a process known as flotation so researchers can learn about the types of plant foods residents consumed and the environment surrounding Cloverfields. Flotation separates carbonized material from other artifacts and soil by using their differing densities. As soil is poured into the tank, the lighter carbonized remains float to the surface, while heavier soil and artifacts sink (Fig. 1). This process gently collects fragile carbon so it can be analyzed.
A wood-lined cellar, Feature 341 (Fig. 2), identified in the concrete addition to the rear of the back building and which contained artifacts dating to the mid-18th century provided abundant ashy soil samples to process for collecting botanical remains. The pit was located in front of a fireplace and the ashy soils within likely represent hearth sweepings. While there is still much analysis waiting to be completed on the collected carbonized remains, bread wheat grains (Triticum aestivum), corn kernel and cob (Zea mays), Plum (c.f. Prunus domestica), Apple or Pear (Malus sp.), Squash (Cucurbita sp.) and Peach pit (Prunus persica) have already been identified (Fig. 3). In addition to carbonized seeds and pits, charred fragments of food are also present. These fragments appear amorphous with an almost foam-like texture, and could be evidence of bread, porridge or starchy vegetable remains. The use of imaging from a Scanning Electron Microscope (SEM) can be used to identify which plants compose the amorphous fragments.
Historic documents pertaining to Cloverfields list a variety of plant resources both in storage and growing in fields near the main house. William Hemsley’s 1738 inventory lists over 464 bushels of corn and other inventories mention bushels of rye, wheat, barley and beans. Although orchards are not explicitly noted, the presence of a cider press and stills alongside apple seeds implies that apple orchards were likely maintained nearby.
Sorting through the flotation materials will take time, but it is already clear from the variety of fruit and vegetable remains thus far identified, that further analysis will provide information on the types of plants both being cultivated and growing wild at Cloverfields.
This article can also be found under the archaeology section of the website here.
By: Devin S. Kimmel, of Kimmel Studio Architects, for the Cloverfields Preservation Foundation
Graham, Willie, “Interior Finishes,” in: Carson, Cary, and Carl R. Lounsbury, eds. The Chesapeake House: Architectural Investigation by Colonial Williamsburg. UNC P Books, 2013. 312-47.
Graham, Willie, “Timber Framing,” in: Carson, Cary, and Carl R. Lounsbury, eds. The Chesapeake House: Architectural Investigation by Colonial Williamsburg. UNC P Books, 2013. 306-28.
Rideout V, Orlando, “Clovefields,” in: Miller, Marcia and Orlando Ridout V, eds. Architecture and Change in the Chesapeake: A Field Tour on the Eastern and Western Shores. Crownsville, Md.: Vernacular Architecture Forum and the Maryland Historical Trust P, 1998. 83-84.
Swann, Don. Colonial and Historic Homes of Maryland: One Hundred Etchings. Johns Hopkins UP, 1939.