The Roman Road Project - Using a Groma

I've always wanted to build and use a groma, the famous surveying tool of ancient Greek and Roman civil engineers. With it the Romans built roads so straight, they still have people scratching their heads wondering how they did it.

                                                            (c) Matthias Kabel

I begin every Roman Technology lesson with the question "How do we know about this object, tool, or process?" And then I take students through the literary, archaeological, epigraphical, numismatic, etc., evidence for it. There's not much out there about the groma in literature, but my students will love seeing this mosaic decoration from the house of a land surveyor in Pompeii:

And the metal fragments of this groma found in the Shop of Verus, the Blacksmith, in Pompeii (I.6.3)...if I can find a picture of them. 

And this gravestone of a land surveyor with this inscription and wonderful image of a groma: 

Our Roman Road Project is the perfect opportunity to learn this tool, but I knew I was going to need help. I've read extensively about their use in books like Lewis' Surveying Tools of Greece and Rome, but you probably know how it is - unless you actually use one yourself, no video or book is going to be good enough.

Earlier this month, I finally got a chance to talk to Dr. Courtney Roby of Cornell University via Zoom. We met at the virtual 2022 annual meeting of the Classical Association of New England to which we were both invited to speak on our ancient STEM classes. (Her excellent book, Technical Ekphrasis in Greek and Roman Science and Literature: The Written Machine between Alexandira and Rome, Cambridge University Press, 2016, is linked here.) Her presentation was about her hands-on lesson using a groma she built to lay out the plan of the ancient porticus Pompeiana on her school's football field. I knew immediately that we needed to chat at some point in the future, and we've been emailing back and forth about numerous things since then.

Talking to her was an epiphany! I finally understood using the groma, and what to look for in sighting. She also talked about the importance of pacing and measurement in ancient surveying. She gave me some great ideas on how to teach the Roman pace, as she does with her surveying project. I'm truly thankful to her for sharing her lessons and taking the time to explain the groma to me. This project is indebted to her!

Now...to build a groma.

Some resources you may find helpful:

Lewis, Surveying Instruments of Greece and Rome

I've searched far and wide, and this reenactor describes best how to use a groma.

This student built one for a class project, and her telescoping innovation looks helpful.

The Roman Road Project - A Visit to the DOTD

I'm fortunate to have a husband who studied classics in high school and college and who still takes an interest in it. When he heard about the Roman Road Project, he suggested I reach out to the Department of Transportation and Development for assistance. To be honest, I was skeptical - what would modern engineers know about ancient road building?

But then, my husband played soccer with a guy who worked for DOTD, and when he told him about our Roman Road Project, he said he knew "just the guy." He offered a name and contact info. Still skeptical, I said I'd get to it later.

My school held a parent open house night in late August. I put out sign-out sheets for parents to volunteer with upcoming projects. I had a parent stop me later that night and ask if he could help with the Roman Road Project. "I work for DOTD, and I know just the guy who could help y'all. He's my boss. He just loves stuff like this." And guess what? It was the same name. That's when I knew I should really email "that guy."

I emailed him the next day. Dr. Tyson Rupnow, Ph.D. and P.E. (professional engineer), is the associate director of research at Louisiana's DOTD, and he got back to me almost immediately. "I would love to help you with your project," he wrote. "I studied and wrote about Roman roads in my engineering Ph.D. program." (!!!) Now, I was really intrigued!

In November, Tyson invited me to the Louisiana Transportation Research Center, and I had a spectacular visit. I never knew all the research that goes into modern road materials science, and at this lab, I got a first-hand look at that. Engineers test materials in special climate-controlled rooms with different types of lighting to simulate outdoor conditions.

In this picture, I'm feeling the heat coming off this asphalt "cake." They regularly pull these out of the "oven" to test in different ways.

They also cut them up for different types of tests. You can see the gravel aggregate in this sample.

Most interesting to me was their concrete core testing room.

Besides all the cool lab stuff, I got to talk to Tyson about our project and how he could help us. I was amazed at all that he offered. He'll be doing lectures on ancient Roman roads, getting us supplies at cost, talking to the students about jobs and training in civil engineering, and guiding us in every aspect of the project. "Don't think I'm going to visit for one day and forget y'all. I'm going to be there every day. This kind of work is part of my job at DOTD."

And it turns out, modern civil engineers learn a lot about Roman roads in their training! For once, I was glad I listened to my husband. (Thanks, David.)

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