Ptolemy IV coin found in Queensland – Part 2

The first part of this post discussed the discovery of a Ptolemy IV bronze coin, dating from 221-204 BC, by a farmer in north Queensland in 1910.  In this part we discuss the coin itself and identify some problems with the evidence that need to be resolved before it is used to support any claims for Egyptian contact with Australia.

Two coins

The first significant problem is that Henderson found only one coin, but Terry and later Gilroy illustrated two different specimens that are each supposed to be the actual coin.  The photo included in Terry’s 1966 and later articles is clearly different to the one shown by Gilroy [1995: 256].

Both coins shown in Figure 1 [Terry] and Figure 2 [Gilroy] – are bronze coins of Ptolemy IV, known as ‘Philopater’ to distinguish him from the other 15 Ptolemies who eventually ruled Hellenistic Egypt prior to its incorporation into the Roman Empire.  Ptolemy IV reigned from 221 to 204 BC.  The coin depicts him on the obverse in the guise of Zeus Ammon, signified by ram horns, and the obverse has an eagle with spread wings grasping thunderbolts.  Along the obverse can be read the inscription ΠΤΟΛΕΜΑΙΟΥ ΒΑΣΙΛΕΩΣ  [‘Ptolemy King’ in Greek].  Between the eagle’s legs there is a small star.  This is a control mark that indicated it was minted following an undated monetary reform during Ptolemy IV’s reign.

”]”]According to the descriptions both coins measure about 35 mm in diameter, but are not perfectly circular, and are about 6 mm thick.  A blind hole appears in the centre of both coins, a common feature on Ptolemaic bronze coinage.  A coin of this type should weigh about 35-36 grams.  The coins were stamped from circular blanks or flans with a fixed lower die and an upper hand-held die struck with a hammer.  In authentic examples the hole passes through the coin.  When Terry’s coin was examined it was attributed to mintage in the Alexandrian city of Barce based on the detail of the design features.  This may not be clear-cut as other cities in Cyrenaica produced coinage that was essentially identical [DHN 2011].

The Terry coin is in good condition with some wear.  In contrast the Gilroy coin is heavily corroded, and appears slightly distorted, with the reverse side appearing to be slightly concave.  It also has a substantial notch missing on the perimeter near the eagle’s claws.

The Terry coin was used to illustrate articles he wrote about the coin, and the original print is believed to be in his papers held by the National Library of Australia [Terry 1965, 1966, 1967].  An article by Gilroy published in August 1978 includes a picture of the Terry coin [Gilroy 1978].  It is likely that this article was submitted for publication before Gilroy’s visit to Queensland that year where he intended to examine the coin himself, as it contains no mention of meeting anyone associated with the coin.  All subsequent Gilroy articles use images of a different coin.  As discussed above in Part 1, Gilroy is inconsistent about how he says he gained access to the coin and is unclear about who owned the coin at the time.

Unfortunately the pictures of the Gilroy coin are not clear enough to definitively say it is or is not the same coin, although it does seem to differ in details.  However, these may be photographic distortions or relate to recent damage.  Is it possible that they are actually the same coin, which has been severely damaged between Terry’s initial inspection in 1963 and Gilroy’s visit in 1978?  Although it seems unlikely that the severe deterioration and damage visible in Figure 2 could happen it needs to be excluded.  To do this a simple test was devised.  Because they were individually hand-made the images were not always properly centred, and also the top die could be oriented differently to the bottom die on each coin made.  As a result, when the head of Ptolemy is the right way up, the eagle on the back may be right side up, on its side or even on its head.  If Terry and Gilroy show the same coin it should have the same orientation and relationship between the two faces.

Using tracing paper, the outlines of the front and back of each coin were matched, making sure that the centre hole was exactly located in the same position.  Two lines were plotted on each coin – one from the centre hole to the tip of Ptolemy’s nose on the obverse, and other other from the centre hole to the back of the eagle’s right claw on the reverse.  These points were chosen because they were clearly visible on each of the photos of the coins.  The angle between the lines was measured.  On the Terry coin the angle between the lines is about 85 °, while on the Gilroy coin it is 60°.  We have to conclude that they are different coins.

Potential fake

The other significant concern comes from examining the best quality photographs of the Terry coin.  These show the obverse side with pitting in different locations [Figure 3].  This pitting is one of the characteristics that coin experts use to determine the authenticity of ancient coins.  The pitting is caused by bubbles introduced into the molten metal rapidly cooling down as it is introduced into the mould.  The bubbles may be completely closed over when removed from the mould but the extremely thin metal between the bubble and the surface corrodes over time, leaving distinctive pitting across the surface [Prokopov 2011; Calgary Coin 2011].

In authentic coins the surface will show very slight corrosion across the entire surface rather than uneven depressions.  Compare the surface detail shown in Figure 3 with any of the Ptolemaic bronze coins shown in this comprehensive portfolio [Ptolemae Project 2011].  Authentic coins struck from flans will have no pitting.

Figure 3.  Casting bubbles on the Terry 1910 coin marked by red circles.

According to Terry the coin had been examined by ‘a coin dealer and foundation member of the Brisbane Numismatic Society’, and he also sent a plaster cast to the Museum of Applied Arts and Sciences’s numismatist [Terry 1966].  Their responses assured him of its authenticity.  These experts may have not have been aware of the tell-tale signs of forgery or may have not handled sufficient ancient coinage to get a feel for the real thing.  Alternately, as often happens, they may have been caught up in the excitement of the speculation and not been as critical as hoped.

Both Terry and Gilroy draw significance from its discovery before the Great War, which reduced the likelihood that it was brought to Australia more recently.  This is not correct, as noted in another blog entry there had been concerns about the importation of forged antiquities and relics into Australia in precisely the period when Henderson is supposed to have found the coin.  While the influx of Australian troops during the Great War is likely to have boosted the amount of both real and fake material that came back to Australia, it certainly was already sufficiently large before the war to generate complaints.

At present the photos available of Gilroy’s coin do not allow a close examination of surface detail.

Continue to Part 3 or go back to Part 1.

Since Parts 1, 2 and 3 were written more research has been done to solve the mystery of the two coins.  Find out in Part IV.