Drag. I guess that takes you back to Trinopus’ suggestion:
I came across this. Its not a complete artifact, but has pretty detailed measurements:
Thanks, but again the hole sizes are tantalisingly absent. It boggles my mind that these objects are very often described as having holes of different sizes, yet nobody seems to think that’s important enough to warrant listing them.
If you have dimensions of the sides, and you have a photo, you can determine the hole sizes with a little bit of scaling and adjustment for parallax/perspective.
You can, but again, there does not seem to be a complete set of views for any single example. So I’d be missing the sizes of the holes in opposing faces, which I suspect may be crucial if the purpose if the object involves sticking something right through it.
There’s a recent theory published by an Italian lady that different sizing of holes allows a roman soldier to sight through it, viewing markings on a roman standard, to estimate distance. Paper published this spring.
This fellow seems well educated and funded apparently, but is probably headed in the wrong direction. Thinks it is related to measuring volume of an object in 6 directions and that this was totaled up using advanced math and roman numerals (!) to act as a 3D scanning tool for small objects.
http://www.romansystemsengineering.com/
Found an interesting drawing that was used by a museum in Zagreb, Croatia for a temporary exhibit, ending a couple months ago. Emailed them to try to get a copy of the drawing, but no results yet. Would like to know where the drawing came from. There are actually a couple posters that use the drawing, but pictures cover up much of the drawing. Have created a CAD drawing using these as an underlay and it is about 80% or so complete.
http://www.amz.hr/home/virtual-walk/temporary-exhibitions.aspx
The best measurements I’ve found, include the hole pair sizes, but is in German:
http://www.wingarden.de/wing/dodekaeder.html
It also mentions replicas being sold at the museum giftshop.
Shapeways, the 3D printing house also has a Roman Dodecahedron in white plastic for sale for about 15 bucks.
It seems to help Google searches to adjust your allowed language settings BTW.
some non-English terms: dodekaeder , dodekaedar , Römische Pentagondodekaeder
… and as I was reading through the previous replies, I found myself thinking, “This sounds like a job for a 3-d printer…”
Geometric notes:
12 (pentagonal) sides
6 pairs of holes
20 vertexes (little balls at corners, perhaps representing stars or planets, act as legs)
30 edges
Best guesses for use:
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a cosmological model, the concept of aether (5th element), a theoretical arrangement of celestial bodies in space, a fun thing to puzzle the mind a little and help think outside of boxes. A sign or symbol of a mathmatics related cult such as Pathagoras.
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combination pencil/pen holder and scroll placeholder (legs minimize ink smearing, but could damage paper if not careful)
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potpouri (cloth and aromatic herbs inside) (legs promote air circulation) (to repel insects, freshen air, aromatherapy)
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pincushion for diffent sized pins (cloth and fine sawdust filled)
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a fairly poor trivet/candle holder
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a combination of the above.
It would not have been a cheap object to make. It looks like there were two main ways to make them before 3d printing.
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Cut and bend from a template the prepunched sides of flat sheet metal. Solder the edges and solder the little balls to the corners. The balls help join the edges together and hide a rough corner joint by the way.
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Similarly make one out of wax sheet and round balls for the corners. Hot wax fillets used to join the pieces together and smooth edges. Carefully embed in casting sand and pack, and create a throw away mold for lost wax sand casting using hot liquid metal.
Metal was not cheap in the ancient world. I’m a little surprised that there doesn’t seem to be any made of pottery, as this would seem to have been cheaper. And would work fine as a burial object or offering. If these were used for regular tabletop use, however metal would be more durable and practical. Maybe this implies these were not just mantle top nick nacks.
A gambling or fortune-telling tool, as Romans were mad for both.
What is a pasta serving size measure?
I have one I modeled in some CAD software. I 3D printed ones for me and all the engineers in our office as desktop curiosities about a year ago hoping someone would be fiddling with and have a eureka moment. I made all the holes in mine the same size.
Our WAG is that it isn’t really handy for holding anything, once you have one pair of holes occupied the rest are blocked. And as Wonder Wheeler said they would be damned hard to make using primitive methods – too time consuming to just be a display piece we think. So far nobody has had a epiphany about what they might be.
I could send you the STL file I used to print them if you’d like it.
Not to be a nay-sayer, but there are no markings on any of the sides. You would think that a fortune telling tool would have the name of a card, or the name of one of the zodiac characters or something. Just different sized holes, and sometimes a different number of rings around a hole.
Drunken games would get bloody if people had to argue about the relative size of a hole one would think…
Even as a pasta serving instrument, it should have the number of servings by each hole one would think. Two dots versus three dots et cetera.
The lack of names or numbers around the sides seems to imply that it wasn’t really important WHICH side you were looking at. That implies it wasn’t some kind of instrument for gauging anything.
BTW, when doing manual drafting in the days before CAD, we used to put dimples or something (like taped pennies) to act as little feet under our plastic templates to try to keep the bottoms from rubbing against the paper and smearing ink (and to some extent graphite). The feet of the Roman Dodecahedrons remind me of those.
The dodecahedron of Tongeren has the following dimensions:
Total height: 81 mm
Height without balls at the corners: 66 mm
Weight: 172 g
diameter of the openings on opposite sides:
10.6 to 13.0 mm 13.8 to 14.0 mm 25.2 to 27.0 mm
23 0.0 to 26, 15.6 to 17.8 mm 20.3 to 20.5 mm 3 mm
China Guy: A pasta measure is something with three or four holes in it. Stick a bunch of uncooked spaghetti in a hole maybe an inch in diameter and if it fills it up, its a certain number of servings, maybe two for instance.
Thanks for reviving this thread with some great data and suggestions. I still have this listed as a project. I’m on a mobile device at the moment - will respond properly a little later.
I think your translated measurements are just about all I need to be able to crack on with this project now, My plan is to design the pentagons on the computer, print them out, then use them as templates to cut flat wax sheets - I can then chamfer the edges of these and join them into a dodecahedron - the corner balls can be made as separate little wax mushrooms and set into each corner.
I’ll then embed the wax form into plaster of paris, melt out the wax and cast in pewter (not exactly authentic, but I’ll then copper-plate it, so it’ll look OK.
My current thoughts on the thing:
The pairs of facing holes are different - so it’s not for measuring something that passes continually through (not pasta then). It could easily be intended for measing tapers on spear shafts (so they fit in standard metal spearheads being made elsewhere).
I don’t believe the weight is exactly critical, and it seems to me this is more likely a physical tool or measuring than a surveying or astronomical thingumajig.
The other possibility that I think has considerable weight is the notion that this is an apprentice’s masterpiece - an item designed to show the quality of workmanship, rather than have any specific utility.
One factor that I think suggests this: some examples have sides with holes surrounded with concentric ring marks. Other examples have holes with small ring marks dotted around them - now, imaging a written description “A hole in each face, encircled by rings” - and it’s open to either interpretation. Maybe this was an item for which an apprentice metalworker was given a written specification, as a test of craft.
The woman proposing the rangefinder theory has a paper on ArXiv, Roman Dodecahedron as dioptron: analysis of freely available data, with the hole sizes for several specimens.
Taper gauge is a good guess. Along those lines, it could a set of GO-NO GO gauges all in one piece. It could be used to measure a acceptable tolerance of a rod/shaft/sword hilt, etc… The work piece must be small enough to fit in the larger hole but not so small as to fit in the smaller hole. The different combinations could be used for different items. This would go along with being an apprentice’s masterpiece project. Something he makes to take with him when he strikes out on his own and allows him to make standardized items where ever he sets up shop. Different trades could use the same concept with different sizes.
Interesting thread. Thanks for bringing this up. I hadn’t heard of them.
Thanks - that one is really good, because it also includes details of the relative positions of the holes in the finished object - which may or may not be important, or as important as their opposition - but the closer I can get to the real thing, the better - I don’t want my findings to be too confounded by errors I may introduce myself.
I’ve got agreement from a local primary school that when I have a prototype, they’re going to borrow it and use it in an integrated curriculum theme about Romans - and have a go at theorising about its construction and purpose for themselves. Should be fun!
A couple odd things I noticed for what it’s worth. The website where I got the measurements:
http://www.wingarden.de/wing/dodekaeder.html
is rather offbeat. It seems to be proposing a relationship of the device to some kind of old surveying grid, and involves dowsing of some kind!
It also mentions a book in Flemish,
„De Romeinse Pentagon-dodecaeder. Mythe en enigma"
that includes an accounting of most of the one hundred items found, along with their hole sizes. I looked up the book on Google Books, but the only illustrations seem to be of clay pots and such. Maybe I had the wrong book or something.
Also noticed some very small (less than 1 millimeter) errors in the dimensions. Mention them only because they seem to be brought in by the automatic translation software by Google. Commas are used in Germany in the place of periods to show decimals of course. Following is original paragraph in German:
"Das Dodekaeder von Tongern hat folgende Abmessungen:
Gesamthöhe: 81 mm
Höhe ohne Kugeln an den Ecken: 66 mm
Gewicht: 172 g
Durchmesser der Öffnungen auf den gegenüberliegenden Seiten:
10,6-13,0 mm 13,8-14,0 mm 25,2-27,0 mm
23,0-26,3 mm 15,6-17,8 mm 20,3-20,5 mm"
Also noticed (mentioned somewhere else) that the metal for these devices was rather thin, maybe 2 mm thick. As if the lightness was a feature or benefit.
Looked up the Museum Gift Store, but they don’t sell online. Am a little afraid to see how much one would cost in Euros. If anyone finds out please let us know. http://www.galloromeinsmuseum.be/practical_information/museum_shop
Good luck with your Project!