Crawford say on p. 40 of CMRR:
Andrew Burnett acutely points out that the weight standard of the semunciae of the first issue of cast bronze [sc. RRC 14] makes it clear that they represent a point of transition to the second, which is heavier than the first (the reasons are mysterious).
This point is still raised in serious scholarly works such as Alessandro Maria Jaia and Maria Cristina Molinari’s NC piece of 2011 (p. 90). How exactly does this work? And what does it mean?
Here’s Crawford in RRC vol 2 p. 595:
I’m still unclear on the whole subject (hence the blogging about it…). Does it mean that the heavy semuncia of RRC 14 shows a tendency to think about the pound as heavier than 322g?
A 322g as should have a 13.42 ish semuncia as its the 1/24th denomination.
In the ANS collection, the weights are: 19.47, 13.43, 23.78(!), 14.76.
A search of acsearch.info, returned these numbers: 18.49, 14.36, 23.51.
Not a large sample size but woah that’s some variation in the data. And three, maybe four, of these seven specimens weigh enough to be a plausible weight for a uncia in the same series.
The ANS collection has RRC 14/6 specimens weighing: 20.2, 25.73, 29.33, 22.76, 19.64, 20.79, 25.22.
So what about the ‘heavy series’ RRC 18, no semuncia for comparison but we do have an uncia. And remember on weight standard of 334g we should expect as weight of about 27.83 g for the 1/12th piece.
The ANS weights for RRC 18/6 are: 18.1, 18.42, 21.51, 26.13, 28.15, 32.57, 22.97, 39.36, 23.61
Holy variation, batman! But again four of our RRC 14/7’s would fit comfortably into the lower end of this observed data set.
Time to step back and ask a really basic question. How do we know its a semuncia and it goes in this series? I opened up Crawford’s list of the Nemi finds. Not one example of RRC 14/7. There are for context 50 specimens of other RRC 14 denominations including 11 uncia (weights for the four specimens in Nottingham = 28.19, 27.04, 26.77, 27.46, cf. weights of RRC 18/6: 19.96, 29.09, 24.86, 28.55). Jaia and Molinari 2011 (link above) have an appendix of all the hoards of just RRC 14 and 18 aes graves (i.e. those that should have an early closing date). No semuncias. Not surprising really, small change isn’t the most desirable for hoarding.
Well, there is a big sigma on it, right? That has got to stand for semuncia. And we’ve got the comparative evidence of RRC 21/7 with an acorn and sigma on each side. Still. The weights bother me. And it also really bothers me how much the type looks like the obols of Mantineia:
One heck of a coincidence.
And I’m not really less confused that when I started writing this post, but I do have a mad urge to start collecting a big spreadsheet of specimen weights. I’ll resist for now.
Update: See now also this newer post on related material.