RomanArmyTalk
Abacus - Printable Version

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Pages: 1 2


Abacus - Marcus Mummius - 02-21-2011

Salvete,

Does anyone have dimensions of the original Roman abacus this model was based on?

[Image: RomanAbacus.jpg]

Another reconstruction of the same original, shown in the Landesmuseum in Mainz, shows the abacus with beads that appear to be loose.

[Image: 06.abacus.jpg]

Not slidable elements like in the first reconstruction.

Does anyone know how the original was constructed?

Valete,
Jef


Re: Abacus - agrimensor - 02-21-2011

I too tryed to make one but the onlyway (the top one) is to cast it in bronze.
Maybe the one with the bullets is easyer to make but you have to let it be made by a proffesional metalworker (in dutch "freezen")
hope to be some help.
Vale


Re: Abacus - jvrjenivs - 02-21-2011

Why shouldn't one be able to cut a simple version from sheet, Jos? Just a drill, a jewelers saw and a bit of time, I would say.

Anyway, for a nicer one, casting would be easier indeed.


Re: Abacus - agrimensor - 02-21-2011

And more productive (in roman times)
But how does a juwelers saw look like?
(can tell me saturday)


Re: Abacus - Marcus Mummius - 02-21-2011

Hi Jos,

This is a saw like Jurjen means:

[Image: Jewelers-Saw-cutting-out-template.jpg]

Making it isn't really the problem. It's dimensions and the way the original was constructed that I'm after. Sliding knobs or loose balls?

I hope someone can help me with this!


Re: Abacus - jvrjenivs - 02-22-2011

Although it is a very bad picture, the lower one in this pdf shows (according to the description along with the pdf) the backside of an original from the Museo Nazionale Ramano at Piazzi delle Terme, Rome.

To me it seems like they are riveted on the back with some kind of bell-cap (or bell-washer or whatever you like to call it Wink )


Re: Abacus - jvrjenivs - 02-22-2011

Although it is a very bad picture, the lower one in this pdf shows (according to the description along with the pdf) the backside of an original from the Museo Nazionale Ramano at Piazzi delle Terme, Rome.

To me it seems like they are riveted on the back with some kind of bell-cap (or bell-washer or whatever you like to call it Wink ) Anyway, a simple ring will do fine, it seems.


Re: Abacus - Sutoris - 02-22-2011

Took this picture at the National museum in Rome last year.
No dimentions:-(


Re: Abacus - Epictetus - 02-22-2011

According to an older article on Bill Thayer's excellent website:

Quote:The type of Roman abacus which has survived is a small portable instrument with movable beads which could be slid up and down slots. This type, which has some resemblance to the Chinese suan-pan or Japanese soroban, is nowhere mentioned in Latin literature. The two surviving examples, in Rome and Paris, are both about 5 by 3 1/2 inches.



Re: Abacus - MDF - 02-23-2011

Hi Jef,
I was at the National Roman Museum in Palazzo Massimo about 2 months ago.
I saw the abacus (which is the picture Sutoris) and I remember that the size of the long side was about 10-12cm ... it was very small.
The side behind it was impossible to see but I think it's exactly the solution suggested by Jurjen :wink:

If you want to replicate with a simple sheet can drill with a press drill and finish with a round file.


Re: Abacus - Robert - 03-11-2011

[attachment=310]abacusmainz2.jpg[/attachment]

[attachment=309]Ivoor13x8.jpg[/attachment]

This one is made from ivory measuring 13 by 8 cm. This seems to be nearly the standard size, the one shown in the previous post measures 121 by 78 mm.

The upper one from Mainz appears to have a back plate, the other one shown in the previous post with the loose beads is the second origal from Mainz. Looking at the rim, most originals look cast, I am sure Marco is not going to be able to resist doing one :grin:


Re: Abacus - MDF - 03-13-2011

The second one in ivory is wonderful, thanks for post it Robert...yes I will probably build some in the future :twisted:


Re: Abacus - agrimensor - 04-10-2011

Yust a simple one in wood engraved,ballbearings. and written in ink.

salve


Re: Abacus - Sutoris - 04-10-2011

Made the crued form so Jef can do the finishing touch.

[Image: IMG_4791.jpg]


Re: Abacus - M. Demetrius - 04-10-2011

So how was the counting done on one of these? I understand the modern Asian(or is in ancient?)method. Is this similar? I don't decipher the inscriptions, some of them. I'm just and unschooled 21st C Texan. Any pointers?