Cat-o’-nine-tails, from the Mariners’ Museum collection
In the last archaeological blog about the cannon boring project, I focused on why coal is cool. This was probably disappointing for some readers who hoped to read that we found the remains of a cat in one of the cannons. I skimmed over this because I wanted to focus on the cool things we did learn from the cannon boring, but I think it’s time to talk about whether there is ANY evidence, other than Francis Butts’ 1887 sinking account, that there was a cat on USS Monitor …or other ships, for that matter.
Microscopic image of grey cast iron, sampled from a Civil War period Hotchkiss bolt. The squiggly, black lines and nodules are graphite, surrounded by lighter-colored iron.
Last month, we were able to complete one of the last major steps in the conservation of USS Monitor’s two XI-Inch Dahlgren shell guns: boring concretion out of the barrels. Material Culture Specialist Hannah recently showed off what we found in this process (coal is, indeed, cool), but why clean the gun bores to begin with? And how do you actually go about doing that, anyway?
The ‘why’ has a few pieces to it. There are benefits to our archaeological knowledge of the wreck, but our primary concern was keeping the guns in good condition. Monitor’s guns are made of iron, and specifically are made of grey cast iron. Grey cast iron is not 100% pure iron; it contains about 4% carbon, and that carbon exists as flakes of graphite locked in by the metal surrounding it – picture little shavings of pencil lead and you won’t be that far off.Read more
History is filled with ages that are tied to the innovation of materials: The Stone Age, The Bronze Age, and The Iron Age. We are currently in The Plastics Age. Plastics have changed so much in our daily lives. Plastics are around us all the time. They are in every electrical thing in our houses, in the clothes that we wear, in our furniture and the packaging of our food.
This means that as caretakers of historic objects, museums have to consider how long plastic materials will last in our collections. We focus on what we have to do and learn in order to care for plastic objects. We also study plastics in order to store them in ways that better ensure their survival. This is a complicated thing. Plastics are not simple materials, and what works for one may damage another. Some plastics have been around longer than others, so we know more about them. We can see how they’ve aged. For other plastics, we can guess at how they will survive (or not) based on their behaviors and chemistries, while still others are a gigantic question mark.Read more
The archaeological conservators boring one of the two Dahlgren guns.
The Conservation team recently bored USS Monitor’s 2 XI-inch Dahlgren cannons. This was a huge step in the objects’ treatment. It came from a need, but also required the right expertise, a TON of planning, donor funding, and specially crafted parts to make it happen. This task was completed for absolutely no archaeological reason. It needed to happen to conserve the artifacts and, therefore, it happened, but that doesn’t mean that archaeological interpretation didn’t benefit from the project.
So, here is my tale of why coal is cool…
To accomplish “archaeological investigation” of the concretions which came out of the guns’ bores, we set up a screening station at which the screeners – me, and the poor fools I tricked into helping me (our CEO Howard, our intern Christy, and our volunteer Heidi) – broke up the concretion into smaller bits of concretion until it fit through the screen and we could say with fair certainty that there were no artifacts left inside. This is a standard archaeological practice called sifting. What is maybe unique about our situation, is that since everything belongs to NOAA, we don’t get rid of the dirt and rock after its sifted, we bury it and save it in case there are techniques that it will be useful for in the future. No, I won’t tell you where we bury it. Actually, even I don’t know where, so I couldn’t tell you if I wanted to.Read more
It was a crisp winter morning, the year newly minted as it was only January 2nd. I had just finished preparing all of our samples to run on our old, but usually reliable, ion chromatography (IC) unit. (Aside: The IC is vital in measuring when the desalination treatments of USS Monitor objects are complete.)
Our IC unit ran out of preventive maintenance coverage (read warranty) as of January 1st. The IC is so old that parts are hard to find and we couldn’t buy a new preventive maintenance policy on it. Our IC was balancing on the precipice of obsolescence and inactivity.Read more
