In the Krause Standard Catalogs, if I see something like this: Bahamas KM# 19 15 Cents Cu-Ni, 25mm, ... Shape: 4-sided Can it be assumed that the 25mm measurement is diagonal? (It is in this case, because I checked against this very coin ... but are they consistent in measuring non-round coins across the longest possible crossing?)
The older editions showed actual size images. The newer books have many reduced size images, usually without noting that fact with the listing.
I think you are correct in your assumption that the measurement would be from the farthest points. I remember from my first year of mechanical drawing (7th grade, 1959-60) that you constructed a pentagon, hexagon or octagon by drawing a circle and dividing it into the corresponding number of arcs. For example, to construct a pentagon with a 3" diameter, you would draw the 3" circle and mark each increment of 72 degrees (5 x 72 = 360) along the perimeter with a protractor which gives you the five sides. Chris
My bad, forgot to mention that for a square you measure both 9 to 3 and 12 to 6, similar for an oblong piece. Really, you have to use your best judgment.
Please correct me if I'm wrong since I don't collect ancients, but weren't most of them "hammered" using rather crude equipment (as compared to the last couple of centuries)? For example, if no retaining collar was used, wouldn't the metal of the hammered planchet have a tendency to flow away from the area of impact where the greatest force was applied. Aren't many of the coins out-of-round as a general rule? If that is the case, I don't see how you could apply the same standard other than an approximation of diameter. Chris
And? The purpose of providing the diameter is to provide a reader with the size of the coin, even if its an approximation. The same methodology should apply, regardless.
Going back to your comment about taking the measurement 9-3 & 12-6, what happens if the coin is oblong from 1-7 or 2-8? So, my question is why shouldn't the measurement be taken from whereever the two axes may be? Chris
True. Most people will give the min and max diameters of such coins if they are over 2mm difference but things more round are approximations. Many ancient coins are of uncertainly named denominations and will be denoted by metal an size so AE18 is a bronze coin of about 18mm diameter. An AE 18x22 would be a very oval coin. If you have an example of a coin listed in the catalog as an AE18, it is quite possible that yours will be AE 17 or AE19 or as irregular as could be since repeatability was not an important concept in many ancient civilizations and an extra strong hit by the hammerman could make a coin a bit bigger. Most were more concerned with weight than diameter or thickness. There are exceptions where ancient technology made very precise coins the rule but the concepts of bank rolls and stackable coins had not occurred to most of the authorities. Rule makers in ancient coins rarely follow consistent rules. Experts in fourth century AD Roman give little concern to how those in 5th century BC Greek wrote up their coins. Sometimes you will see a book that specifies that they took measurements 9-3 or some other way but someone studying a relatively unpublished specialty is quite likely to pick rules that fit that subject rather than feeling the need to follow random rules of another student.
It seems though that in the newer editions when the coins are not shown actual size, they provide the size in the data listed. In the older editions they do not provide the size, you have to measure them. So swimmingly - pick another coin of an odd shape where they provide you the size, tell me what the listed size is and I'll measure the image in my old editions to get you your answer.
