What can green glass tell us?

Hi there,

Near the end of the dig, my unit partner Kieran found a shard of glass near the southwest corner of our unit around 34 cm below datum. It was a very thick piece of glass, with a beautiful olive green color, slightly curved, and full of bubbles, resembling old bottle glass. This was the biggest piece of glass we had found, and we found the color and shape to be quite intriguing. It made me wonder: How were glass bottles made in the 18th century? Could we find the particular usage of this type of glass/bottle? 

A picture of one green
glass bottle found at Cahokia

After some research, I found some information that answered my questions. In a colonial Illinois village called Cahokia, archaeologists uncovered 18th-century bottle glass fragments that were dark green and hand-blown. These were characteristics of glass bottles made by French bottle makers in the 1700s. The procedure for creating these glass bottles goes as follows:

“Sand and wood ash are melted in giant iron pots placed on a red-hot flame to form molten glass. Sand could be made from a variety of crushed rocks ranging from very expensive to very cheap. The cheaper the sand, the greener the glass. The assistant gathers a mass of molten glass on the end of a hollow blowing pipe and inflates it like a soap bubble into a mold. Molds enabled bottle makers to mass-produce bottles that held the same amount of liquid. The assistant transfers the bottle from the blower's pipe to the pontil iron. The pontil iron is used to support the bottle while the glassmaker forms the neck of the bottle. The pontil iron is also used to push the base of the bottle up into its interior, forming the 'Kick-up.' The kick-up served two purposes: to make the bottle stronger and to catch the dregs of the wine--solid matter left over from the wine-making process. The bottle is removed from the pontil-iron, leaving a pontil scar on the base of the bottle, and then left to harden as the glass cools.” Illinois State Museum, 1996.

The bottles found from the site in Cahokia were exported from France and shipped to New Orleans and Illinois, and Illinois is pretty close to southwest Michigan. They appear to be a very similar color and thickness as the glass shard from our unit, though it can be hard to tell. This makes me wonder if glass bottles were exported from Illinois to Fort St Joseph, or if they were brought to the fort via the Great Lakes.

Glass bottle fragment found in our unit. 

I am also curious about what these bottles were used for. One theory I have is for wine. The existence of wine at the Fort has been documented. In a previous FSJAP blog post made ten years ago, a student stated that “wine bottle fragments are common, and are typically olive green,” and that at the fort, “ glass for liquor containers, wine bottles, and oil, medicinal, and many other containers of varying color have been found, as well as some tableware and a lot of window glass” (Gerechka, 2013). So we do have some evidence that the people of Fort St. Joseph were wine drinkers. The wine imports not only came from France but from Britain as well, and both countries have great influence over the fort. In the 18th and early 19th centuries, “The ‘wine’ bottle was the principal product of British bottle-glass factories... The bottles were used to ship, store, mature, and serve a variety of products, primarily beverages, and were widely used not only in Britain but also in her colonies and in other countries that traded with Britain” (Jones, 1984). Britain often traded wine with France, and at Fort Saint Joseph, so there was a constant cycle of trade throughout the three different countries.

The shard of glass we found near the end of our dig season gave us additional evidence as to what the people of Fort St. Joseph may have been doing hundreds of years ago. It also paints a picture of what may have happened in our unit. Maybe people at the fort has a great taste for wine. Though we may never get an official answer, small finds like these help us dig further into the history of the fort, one step at a time.

- Alivia

Sources:

At Home: 1700: Behind the Scenes. (December 31, 1996). Illinois State Museum. https://exhibits.museum.state.il.us/exhibits/athome/1700/activity/behind/frenchbot.htm

Gerechka, A (2013). At FSJ the Glass is Half Full. Blogspot.com. https://fortstjosepharchaeology.blogspot.com/2013/07/at-fsj-glass-is-half-full.html

Jones, O. Cylindrical English Wine and Beer Bottles 1735-1850 (1984). https://sha.org/assets/documents/Cylindrical%20English%20Wine%20and%20Beer%20Bottles%20-%20English.pdf