Thus wrote Archeologist Eric Schweickhart, who came to Menokin to research our 18th century nails.
Here is the report he sent us to share with you.
On January 14th 1765, a number of men from Prince George’s County, Maryland gathered at Oxon Hill manor to inventory the estate of the recently deceased John Addison. In his cellar they noted finding “5,000 10d Nails” which he was presumably storing for some future construction project.
In the 1700s, blacksmiths made nails by hand, cutting long iron rods into sections which were each given a head on one side and tapered into a point on the other. The length of each of these sections, and therefore the length of the finished nails, varied according to the needs of the buyer. Thin wooden lathing, which was plastered over to create interior walls and ceilings, could be secured with nails about an inch long but thicker clapboards, rafters, and roofing shingles required longer nails. Therefore, a system had been developed in England to sell nails in sets of 1000 according to their weight. Since a thousand three-inch-long nails would weigh more than the same number of two-inch-long nails, buyers could know the average length of the nails they were purchasing. When sold, nails were given a classification (4d, 5d, 6d, etc.) to indicate their weight and if this system was anything like the 19th-century American ‘penny nail’ system, as many believe, then each of these categories represented a quarter-inch difference in length. Thus, Addison’s 10d nails would have probably been about three inches long, on average, but if they were 8d nails they would have been about 2 ½ inches long.
Knowing the size designation of nails found at a site would be a useful analytical tool for archaeologists. When a nail is dug up during an excavation it is usually completely removed from any context that could be used to identify what wooden elements it once held together. Nails found in the ground were generally either pulled and discarded or the wood that once surrounded them has long since rotted away. However, since particular sizes of nails were used for particular purposes, the presence of those nails could be used to better understand the nature of the site. For instance, a large number of nails about an inch long found at an excavation could be evidence that a house with lathing inside once stood on the site.
Additionally, if the same size nails are found at multiple sites in the same area, they may suggest that local people were buying nails from the same source or even that nails from one structure were salvaged to build the other. In order to assign excavated nails to particular size categories, some archaeologists measure their length and round them to the nearest quarter inch.
While this technique seems to work well on 19th-century sites in America, when most nails were made with machines, earlier nails made by hand could potentially have much more variation in size. Since nail sets were determined by weight, a nail considerably smaller than the ideal size could be included in the set if it also contained another nail considerably longer than average. Thus, the problem is: how can we be sure that a hand-wrought nail that rounds down to two-and-a-quarter inches long was not sold as part of a set of 8d (2 ½ inch long) nails?
Luckily the collections at Menokin are uniquely suited to answering this question. The incredible work done by the staff at Menokin to curate and identify the architectural elements which are no longer attached to the structure has created very useful dataset.
When Francis Lightfoot Lee had the manor house at Menokin constructed in 1769, his architect and carpenters acquired thousands of hand-made nails specifically for the structure. Since these nails are still embedded in the wooden lathing and roofing elements that have been carefully recovered and analyzed to determine their placement in the original house, they provide an opportunity to study nails which are known to be purchased as part of the same set. This process was more difficult with sections of the roof than with sections of lathing because the roof was repaired several times using different types of nails, but a number of the original 18th-century roofing beams, with their original nails, still exist. By carefully measuring the lengths of nails in several different architectural elements at Menokin, the general degree of size variation within sets of nails made by blacksmiths can be determined.
The results of this analysis were astounding. Despite the fact that there was about half-an-inch difference in length between the longest and the shortest nails from each architectural element, when all the nail lengths from any one wooden element were averaged together they fell within .05 inches of their ideal length.
For example, of the 50 nails measured from a section of lathing that was once part of the northwest ceiling of the mansion (2006-357), the shortest nail was 1.02 in. long and the longest was 1.52 in. long but the average nail length was 1.246 in., suggesting that they were all bought as part of a set of 3d nails made to be one-and-a-quarter inches long. If this section of lathing had been left to rot away and only the nails were recovered and measured to the nearest quarter inch, 5 of them (10%) would be classified as 2d nails, 39 of them (78%) would be classified as 3d nails, and 6 of them (12%) would be classified as 4d nails.
Each of the architectural elements analyzed at Menokin had similar bell curves, with the nails equally distributed above and below the ideal length and a small number of longer and shorter nails rounding to the next size up or down. The Menokin dataset suggests that in the 18th century, between 20% and 50% of the nails sold as part of a set were closer in length to other size categories than to their given category. However, in every case examined, the number of nails that fell into the smaller category was almost exactly the same as the number that fell into the larger category.
Therefore, thanks to the commitment of the Menokin staff to the conservation and analysis of the home of Francis Lightfoot Lee, archaeologists are one step closer to being able to understand the decisions made by the people who once lived at the sites they excavate. This analysis suggests that if the lengths of hand-wrought nails found at a site fit into a bell curve around a particular ideal length with between 10% and 25% falling into the next smallest size category and roughly the same amount falling into the larger size category then they were probably acquired together as part of one set. If the nails at a site do not fit into this pattern, they may have been sold as part of separate sets or were made by local, enslaved blacksmiths who might not have packaged their work in the same way that British nail-makers did. With this information, archaeologists can begin to make interpretations about the architectural elements people incorporated into their homes and workplaces, the access particular individuals had to the various networks though which nails (and other goods) were exchanged, and the extent to which common knowledge about what size nail was most appropriate for a task was shared between neighbors and families.
I would like to thank Sarah Pope, Alice French, and the rest of the Menokin staff for their help and patience. I appreciate their willingness to take time out of their day to help an archaeologist with his odd requests. I would also like to thank Barbara Heath and Matt Reeves for their guidance.
A Special Treat
Menokin Trustee and professional photographer Hullihen (Hullie) Williams Moore also has a fascination with Menokin’s nails. Here is a photo gallery of some of his work on the subject.