I’m still sick and it is for the birds. I do feel I’m on the mend though. But I’ve caught up on emails for the most part and otherwise cleared the decks to really start crunching my data so far and then build this slide deck for the conference in Rome next week. I’m going to keep this short as time and energy are at a premium.

The following article really felt a game-changer for my understanding of what I’m seeing in the data. The lead authors are known to me from a number of their other publications which I often cite, but this one really got to the heart of the matter of intrinsic value. Back in 2006 they had already came to conclusions through their testing that I personally reached back in 2019 with my meteorological work on RRC 14, 18, & 19 (final text, I’ve seen proofs so it should be out later this year). This and their careful thinking about bronze recipes will really strengthen my initial report on my data to say nothing about what the next steps are.

Ingo, G.M. & De Caro, Tilde & Riccucci, Cristina & Angelini, Emma & Grassini, Sabrina & Balbi, S. & Bernardini, P. & Salvi, D. & Bousselmi, Latifa & Çilingiroğlu, Altan & Gener, Marc & Gouda, Venice & Al-Jarrah, Omar & Khosroff, S. & Mahdjoub, Zoubir & Al saad, Ziad & El-Saddik, W. & Vassiliou, P.. (2006). Large scale investigation of chemical composition, structure and corrosion mechanism of bronze archeological artefacts from Mediterranean basin. Applied Physics A. 83. 513-520. 10.1007/s00339-006-3550-z.

FULL TEXT

Abstract:

A large number of Cu-based archaeological artefacts from the Mediterranean basin have been selected for investigation of their chemical composition, metallurgical features and corrosion products (i.e. the patina). The guidelines for the selection of the Cu-based artefacts have taken into account the representativeness of the Mediterranean archaeological context, the manufacturing technique, the degradation state and the expected chemical composition and structure of the objects.
The results show wide variation of the chemical composition of the alloys that include all kinds of ancient Cu-based alloys such as low and high tin, and also leaded bronzes, copper and copper-iron alloys. The examination of the alloy matrix shows largely different metallurgical features thus indicating the use of different manufacturing techniques for producing the artefacts. The results of the micro-chemical investigation of the patina show the structures and the chemical composition of the stratified corrosion layers where copper or tin depletion phenomenon are commonly observed with a remarkably surface enrichment of some soil elements such as P, S, Ca, Si, Fe, Al and Cl. This information indicates the strict interaction between soil components and corrosion reactions and products. In particular, the ubiquitous and near constant presence of chlorine in the corrosion layers is observed in the patina of the archaeological Cu-based artefacts found in different contexts in Italy, Turkey, Jordan, Egypt, Spain and Tunisia. This latter occurrence is considered dangerous because it could induce a cyclic corrosion reaction of copper that could disfigure the artefact.
The micro-chemical and micro-structural results also show that another source of degradation of the bronze archaeological artefacts, are their intrinsic metallurgical features whose formation is induced during the manufacturing of the objects, carried out in ancient times by repeated cycles of cold or hot mechanical work and thermal treatments. These combined treatments induce crystallisation and segregation phenomena of the impurities along the grain boundaries and could cause mechanical weakness and increase the extent of the inter-granular corrosion phenomena.

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In other news, I think I have my Nottingham dates to work on the Nemi material in May and my colleague Wayne Powell is coming with me and that means the science end of this work will be able to appear in a co author publication at some point to match my numismatic and historical approaches. He’s a bronze expert esp. tin isotopes among other things. Particularly awesome is his most recent publication on the Uluburun shipwreck and how it updates our understanding of tin trading and community connections. If you like that sort of thing you might check it out.

I’m sick, nothing special, just old-fashioned winter cold. I keep overdoing it before I’m fully well and then backsliding. Not a good pattern. I’m trying to slowly tend to communications and other tasks and nurse this pot of tea.

Anyway, I was looking at Crawford’s catalogue of the Nemi material to give the Nottingham curator how long I might wish for that visit later this year.

I was struck by the large numbers of RRC 38/7 and the pretty remarkable number of RRC 38/3 as well.

The former Mercury-Prow struck piece seems to average in the 6-4 grams range, and this small Roma-Prow seems to fall in the 3-1.5 grams range. (I’m eyeballing not actually running the numbers here!)

What really gets me is that this is the only so called quartuncia in the whole series. There are more of this type of semuncia to follow that look very similar and also are without a denomination mark but previous semuncia absolutely had a denomination mark and very late semuncia also had denomination marks (all semuncia types in CRRO).

How would anyone have known that these two coins were these denominations? Clearly they were accepted and readily used and small, light coins are certainly convenient, but after distribution as pay (if that is how they entered circulation), how did they come to be accepted and spendable at a specific monetary rate. How different at all are these from earlier struck bronze (issued at the same time as cast!), which Crawford called litra or double litra, such as RRC 13/2, RRC 16, and RRC 17 and more (all these types of issues in CRRO). These three show up in the Nemi lists. Why aren’t we calling 38/3 a litra and 38/7 a double litra?!

Grueber BMCRR p.26n.1 says D’Ailly (p. 115) is the first to recognize this denomination and connected it to the semi-libral standard.

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Today, as I’m able:

Book manuscript PR review

article PR review

send emails RE Nottingham

Schaefer

RE April event

that’s more than enough…

I’ve just finished up here at Rutgers and am waiting to discuss my early findings with a colleague, but I have some extra time before he arrives.

I’ve wrapped my head around zinc levels to be satisfied that in a few cases I can reject specimens from my analyses when levels are far too high. The other big interference is Light Elements, basically oxidation. All those readings go out the window too, even when I think the specimen is likely genuine. I do leave them in for other fabric analyses. But then what about other unexpected elements that keep coming up. The list of modern patina chemicals given below is quoted directly from the Newman Portal.

This type of ‘enhancement’ might explain to some degree some of the odd stuff I’m seeing, including perhaps some of the light elements (N, H, O etc…)

A big one that has been turning up is SULFUR. Obviously it could be naturally occurring from the conditions of deposition. Italy has TONS of the stuff. Campi Flegrei ?! This sort of interference from natural incrustation is my first assumption when I turn loads of CALCIUM as well.

—- I GOT MY FUNDING TO GO VISIT THE NEMI MATERIAL—

[That news came in as I was typing: had to share in real time.]

The other thing that shows up is CHLORIDE which is associated with bronze disease. On some specimens I suspect it is in fact bronze disease, but I wonder if in some cases it might be ‘enhancement’. Wouldn’t the use of this in patina creation be a bad idea? Couldn’t it lead to bronze disease and irreversible damage?

The other real insight was the use of BARIUM in the creation of patinas, I’d gotten some really surprisingly high barium readings and really was flummoxed by that until reviewing this list.

I also found the use of IRON in these patina’s a little surprising. Iron does show up in my readings but as it showed up in high levels in ramo secco (Burnett, Craddock, Meeks 1986) I thought it was most likely naturally occurring. I wonder if I could spot the associated nitrate salts.

The final element that has shown up that I don’t know if it is natural or not and isn’t in this list is SILICON. In the modern world there are manufactured silicon bronze alloys but I highly doubt anyone has used these to fake coins.

Please don’t take anything in this post as ‘fact’. I’m still thinking through the material and trying to make up my mind what to think.

[begin quotation]

Patina chemicals.  The following chemicals are some of the more frequently used in patina finishes:

Ammoniumcarbonate  (NH4)2 CO3.H2O.  A mixture of ammonium bicarbonate and carbonate. Used for a bronze patina of bluish-green color.  Also called “hartshorn.”

Ammoniumchloride  (NH4Cl) A patina solution for coloring bronze a verde antique green.  Also called “sal ammoniac.”

Ammoniumsulfide  (NH4)2SO4  An excellent darkening agent for bronze and silver in highlighting during a finishing operation. The objects to be darkened are immersed in this chemical for less than ten seconds – the sulfide is the source of sulfur as the darkening agent.  Also called “sulfate of ammonia” and “sulphuret of ammonia.”

Barium sulfide  (BaSO4)  Used as a coloring agent for bronze medals for a light brown color, called “Old English.”

Copperchloride  (CuCl2)  A patina coloring chemical producing yellowish-green color on bronze.  Also called “cupric chloride.”

Coppernitrate  (CuNO3)  Used for dark blue and green patina coloring on bronze.  Also called “cupric nitrate”

Coppersulfate  (CuSO4)  Colors bronze green. It is the green corrosion on copper items in an atmosphere exposed to sulphur and moisture over long time.  The composition of incrusted patina.

Ferricnitrate  (Fe(NO3)2)  For use only by very experienced finishers; colors a dark chocolate color. Care must be used, however, as some of the nitrate salts can spot the surface.      

Liversulfide  (K2S)  Used for a bronze patina on statues and medals; it produces a color from redbrown to dark brown.  Also called “liver of sulfur,”“potassium sulfide,”  “sulfurated potash.”

Liquidsulfur.  (S)  Quickly turns bronze and silver a dull black.

Oiloflavender.  A bronze patina of pale ashen green color, formed by adding yellow pigments to oil of lavender.

Potassiumnitrate  (KNO3) is a patina solution for turning bronze a dark red color.  It is most used for tempering tool steel (heat treating dies) and for chemical analysis. It is also called “saltpeter.”

Potassiumpermanganate  (KMnO4)

[end quotation]

Bronze is Tin and Copper, Brass is Zinc and Copper. The latter is far harder to produce than the former. The foundational work on Brass in the ancient world is Craddock 1978. I’m starting here and then working forward in scholarship. The main issues are obtaining zinc and then ensuring it doesn’t burn off when the alloy is made.

Craddock didn’t know exactly where or how the technology enters the ancient world or precisely the techniques used but he makes a good case that the techniques that end up being used by the Roman might have been v similar to those used in India (see diagram below)

The question is how early was brass commonly in use, certainly by the first early century CE. It is known to Plato and other Classical writers but is considered more precious than silver because of its gold color. Even in the Roman world it was valued for this property

Craddock says there are Etruscan figurines of Brass that must be genuine because of style.

But I am more skeptical. I couldn’t find this statue in the BM collection (I didn’t look as hard as I could have.) But I did find another fake brass with the curator’s notes from 1990 saying with certitude that Brass wasn’t used by Etruscans in this period.

Why do I care? Well because of zinc readings from surface analyses of aes grave. Could the material be ancient? I’m leaning very strongly no, but this is just the beginning of my thinking on the matter, don’t base any arguments on this yet.

One more brass object that is suspected of being a modern imitation:

Suffice to say I leave notes in the trays when I find high zinc readings.

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I got two pieces of exciting news today, I can’t share yet but both were just what I needed to hear.

Today

• further edits/tweaks – then send off
• Zoom on back to the 80s
• Rutgers follow up
• Shift Feb flights
• Submit receipts
• Update Rome contacts on Feb
• April NYC event follow up email on state of logistics
• Email Schaefer
• START CRUNCHING DATA

Not Today (but maybe tomorrow, or the day after)

• collect hoard data for RACOM paper
• Teaching requests for Fall 2023
• Set time table for any collaborative RRDP work/publication prep that needs to happen this semester: Chicago pub, INC pub, collaboration with RACOM, etc…
• Circle back to Capito project
• Consider ask for funding from Dean’s office
• Begin Med school rec letter
• record mini myth
• find out what is on that v old harddrive and back up to cloud
• Write up Teaching Eval
• renew Coinarchives

Schaefer archive

In my Satricum post I note that Termeer and Prins 2021 observed there was found:

“one Lion bronze (no. 38) with reverse lion to the left is a variety of RRC 16/1a and 1b, only known from Vicarello and Carsoli”

I made a note in my copy of RRC of the new subtype and moved on, now today while reading Catalli 2014 on the Nemi finds (scan on file), I notice that there too a lion left was listed there among “rinvenimenti soradici” stray finds from the sanctuary area.

How amazingly odd to have a sub-type that keeps turning up well provenanced, but with almost no presence in trade. Of course, Schaefer knows of one such specimen that sold in 1990, but I can find no more with a quick search of the usual databases.

RRC 16

Update Feb 8, 2023:

Crawford knew of 3 specimens of this type from Nemi in 1983 (Whole Catalogue).

This specimen of RRC 14/2 has what might be deliberate cut marks on one side.

This made me think of the chop marks found on struck coins at Satricum which I blogged about last week.

What function could they serve? Definitely not to check purity. Unlikely to be defacement for political/ideological purposes.

The specimen is from the S. Marinella Hoard (CHRR 21) discovered in 1927.

The images are from BN 13 1989 and Catalli’s republication of the hoard.

Before I get to work on the boring parts of today (persuading two machines to talk to each other via some rather mediocre software), I allowed myself to browse some of my scans from the ANS yesterday. Divo 1977, the coins stolen from Naples, is just one of the goodies (need a pdf? just ask!). [NB! I keep calling this Divo 1970 by accident, no idea why. Must clean up file names etc…]

I may have found a new Fabatus control mark (RRC 412/1). My run through Crawford’s plates LXVIII and LXIX turned up no likely matches. I’ve not spotted it in the Schaefer archive either for all he’s identified dozens of control-marks not known to Crawford (you can access this through CRRO). But I’ll be honest I didn’t give it too much time as other things take priority.

---

Today

• follow up on scans from yesterday
• edits/tweaks – then share
• Princeton follow up
• Read more on Aes Grave
• Rutgers follow up
• Prep PC for tomorrow
• international UG response
• April event logistics
• Cancel at least one more digital membership

Not Today (but maybe tomorrow, or the day after)

• Teaching requests for Fall 2023
• Set time table for any collaborative RRDP work/publication prep that needs to happen this semester: Chicago pub, INC pub, collaboration with RACOM, etc…
• Circle back to Capito project
• Consider ask for funding from Dean’s office
• Begin Med school rec letter
• record mini myth
• find out what is on that v old harddrive and back up to cloud
• Write up Teaching Eval
• renew Coinarchives

It’s an ANS day. I’m spending some time with the SNGs from Italian Collections this from Firenze (vol 3.) Umbria-Bruttium.

I also battled the scanning technology to make a high quality copy of the Divo, Coins Stolen from Naples (1977). I’ve been frustrated with not having it on file. But at long last I’ve a decent pdf (if you need one do ask!).

I’m now scanning most of Bolletino di Numismatica 13 (1989). The images of well provenanced aes grave From the Roman National Museum Collection (Palazzo Massimo) are just delish.

Some Etruscan pieces

Ardea 1940

S. Marinella 1927

Pozzaglia 1922-1923

not only full size images but some in color and all with weights and inv. numbers!

Then this afternoon I go to pick up some metallurgical testing equipment from a colleague’s lab and then I drive home.

More tomorrow…