Got this coin of Empress Julia Mamaea today. It has Vesta on reverse, holding a Palladium and a scepter. Cohen 83 - Ric 708. This coin is my first Sestersius and it weighs 24.54 g. The coin's weight appears to be listed 19.78 g. How come we encounter such a difference in weight?
They always tend to be off a bit around this time period. This is my first Sestertius, which I still have. Her son, which is 19g. Severus Alexander (222 - 235 A.D.) Æ Sestertius O: IMP ALEXANDER PIVS AVG, laureate bust right with slight drapery on far shoulder. R: SPES PVBLICA S C, Spes advancing left, flower in right, raising skirt with left. Rome Mint, 232 A.D. 19g 29mm RIC IV 648
There were two ways of measuring weights of coin flans. Rarely, the mint would adjust a blank to be exactly what it was supposed to be. More often, the mint made a given number of blanks from a given weight of metal not worrying too much that some were a bit over and some were a bit under. Yesterday I made some cornbread muffins. My intent was to make eight muffins all the same but in fact what I did was take eight muffin papers and pour some batter in each one until I ran out of batter. With experience I can do this with some accuracy but it is no big deal since a half ounce one way or the other doesn't keep the things from tasting good. The mint was proabably a bit more likely to assign experienced metal pourers to working with gold and apprentices to the bronze line and, unlike muffins, it is hard to take a spoon and adjust the heavy ones down or the light ones up. Catalogs tend to give averages or theoretical numbers. Even today the US mint lists the five cent coin as 5.000g. Weigh ten brand new nickels and tell me how many weigh even 5.0 rather than 4.9 or 5.1. Today as in the time of Julia Mamaea there was a theory called "Good enough for government work." The fancy term for striking coins so many to the pound is al marco. Weighing each one is al pezzo. The article below will tell you way, way more than you wanted to know. https://www.academia.edu/1443037/Weight_adjustment_al_marco_in_Antiquity_and_the_Athenian_decadrachm
don't these feel great in hand 7C? congrats on your new coin! this is my latest sestertius, it's been a while since i picked one up..faustina jr.
And, if you'ever seen Roman Republic denarii that look like they've had scoops of metal scraped off of them (look around, they are out there), that is evidence of the al marco method of weight adjustment. Metal would be removed from a few denarii blanks in each batch to get the weight of the batch down to spec.
Here is a scoop, or al marco weight adjustment. PUBLIUS FURIUS CRASSIPES (84 B.C.) AR Denarius O: AED CVR, turretted head of Cybele right. Long oval gouge and tool mark across Cybele's head (al marco weight adjustments). R: Curule chair inscribed P FOVRIUS, CRASSIPES in exergue. Rome Mint 3.9g 20.5mm RCV 275 Publius Furius strikes here not as moneyer, but as a special issue in his role as Curule Aedile, hence the curule chair bearing his name.
Adjusting them individually is the "al pezzo" (by the piece) method. That's what Doug said. The scoops (gouges) on Republican coins are not "al marco" but "al pezzo."
My first: Gordian III, AD 238-244 AE, sestertius, 25.46g, 32.5mm; 12h; Rome, AD 238-239 Obv.: IMP CAES MANT GORDIANVS AVG; laureate, draped, and cuirassed bust right Rev.: VICTORIA AVG; Victory advancing left, carrying wreath and palm; S-C
I respectfully disagree. The theory on these scoops is that only a few denarii blanks out of a set number were lightened to bring down the weight of an overweight batch. That's al marco, not al pezzo. Let's say the mint needed to stike 1000 denarii from 3800 grams of silver. The pourers do their best to pour 1000 perfect 3.8 gram blanks. When the blanks are made, ALL 1000. blanks are weighed together, but they weigh 3850 grams. The adjusters then go about scooping 50 grams of silver off of 100 blanks to bring the entire batch to the correct 3800 gram weight. Thus, every coin was not adjusted to correct weight (THAT would be al pezzo). Instead, a group was adjusted to an average weight by lightening only a few coins. If every Republican denarius was adjusted to correct weight, al pezzo, we would see a LOT more scooped coins and there would be much less weight variance. Am I making sense?
The original author about this gouging practice agrees with Carausius and not what I wrote above. Stannard's article "The adjustment al marco of the weight of Roman Republican denarii blanks by gouging" proposes that the average blank was cast a little bit to high in weight (to keep the randomly lower-weight ones from the Gaussian distribution still reasonably high) and then the heavy ones were selected out to be lowered in weight, making the overall total for a batch what is should be [page 49]. He defines "al peso" as "adjustment is intended to bring each individual piece within a certain weight of the standard." For "al marco" he says "weight and tale are managed only by batch, with the aim of getting a fixed number of blanks from a fixed weight of metal, without too much attention begin paid to the weights of individual blanks." [page 47] So, the Romans adjusted the weights of some individual blanks downward. Stannard suggests that is because the total was purposely a bit too high and the total was adjusted downward the right amount by taking some off of selected heavier blanks. Thus the total is adjusted to be right which would in some sense be "al marco." Nevertheless, there is quite a bit of downward variation in weights of denarii as every collector knows. Slightly lighter coins were clearly accepted. I think the mint would be more concerned that heavy blanks would make heavy coins which would be pulled from circulation. They didn't want to give too much silver away. The adjusted coins were, obviously, adjusted individually. All his gouged examples have weights which are in a narrow range around their average of 3.86 grams (the standard is 3.90 or 3.88) which means they were too heavy to begin with and now very close to the standard. Adjusting individual coins seems like "al peso" weights to me. He argues this reduces the tail of the weight distribution at the higher end, which would reduce the total, which is certainly true. But, was this done to reduce the total (Stannard), or to reduce the individual pieces (me)? That is the difference between al marco and al peso.
Very interesting stuff, gentlemen, thank you! This is about silver, but for bronze coins, the weight needed not to be precise, because the metal was not valuable. Isn't that right?
I'm with Carausius on this one. The coins scooped were not always just the heaviest ones but randomly grabbed coins scooped and returned to the batch until the magic number was achieved. There are heavy coins of the types that suffered the practice that were not scooped and underweight ones that would have not have been selected had they been selecting heavies. There are even (rare and I want one) coins that were scooped on both sides when the blank was grabbed twice and they failed to notice that the other side was already done. Were the consideration al pezzo, we would not have overweight unscooped coins or 3.2g (my lightest one, below) scooped ones. Of course some of its weight loss may be porosity. The acsearch one linked below at 4.17g would have been better scooped than my coin. https://www.acsearch.info/search.html?id=1537724 This is another study for someone to do. I don't know how many coins have been studied with this in mind. As far as bronzes are concerned, certainly it would be less important. At the peak of the sloppy standards period is this coins of Trajan Decius weighing 11.2g and looks to have used larger dies as appropriate for the normal 18g sestertii. I once thought it might have been made on a flan intended for dupondii but my actual dupondius of Decius weighs only 7.5g. A highlight related to this matter is the less common Falling Horsemen of Constantius II and (as here) Constantius Gallus which are openly marked 72 for the weight of 72 to the (Roman) pound (328.9g). Mine weighs 4.61g which means it is very slightly heavy (4.57g aim). You can never say anything about how the 'ancients' did something. In this case, I'd say Decius did not care as much as Constantius that year in that mint.
