Further Research
Sub-strains
Sub-strains
During the course of locating the various Unicorn Pennies across numerous collections throughout Australia, the author noticed a peculiarity in the coin designated "UP8".
During the course of locating the various Unicorn Pennies across numerous collections throughout Australia, the author noticed a peculiarity in the coin designated "UP8".
UP8 was the latest Unicorn Penny discovered at the time, and came to the author's attention just before the final draft of the JNAA article was published. Although, counted into the total number of discovered Unicorn Pennies, the author only had a proper opportunity to fully study the coin after the JNAA publication.
UP8 was the latest Unicorn Penny discovered at the time, and came to the author's attention just before the final draft of the JNAA article was published. Although, counted into the total number of discovered Unicorn Pennies, the author only had a proper opportunity to fully study the coin after the JNAA publication.
While the author found most attributes of this coin to be consistent with other Unicorn Pennies, there was a noticeable difference in the shape of the date numeral '3' (see images below). This observation pointed to the possibility of Unicorn Penny sub-strains existing, which suggested that multiple working tools may have been used in the coin's production.
While the author found most attributes of this coin to be consistent with other Unicorn Pennies, there was a noticeable difference in the shape of the date numeral '3' (see images below). This observation pointed to the possibility of Unicorn Penny sub-strains existing, which suggested that multiple working tools may have been used in the coin's production.
UP 2
UP8
UP2 (left) shows a pronounced curvature on the top of the '3' in the date, which is typical of all the Unicorn Pennies. UP8 (right), however, has a considerably less pronounced curvature in the counterpart '3'.
UP2 (left) shows a pronounced curvature on the top of the '3' in the date, which is typical of all the Unicorn Pennies. UP8 (right), however, has a considerably less pronounced curvature in the counterpart '3'.
Interestingly, the '3' in the date of UP8 is very similar in shape to the '3' that appears in the 1930 penny (see below), which suggests another link between the two coins.
Interestingly, the '3' in the date of UP8 is very similar in shape to the '3' that appears in the 1930 penny (see below), which suggests another link between the two coins.
The author has also examined the '3' used in both the 1913 and 1923 pennies (the only other pennies prior to 1930 that featured a date numeral '3') and found that in both coins the numeral is shaped differently to UP8.
The author has also examined the '3' used in both the 1913 and 1923 pennies (the only other pennies prior to 1930 that featured a date numeral '3') and found that in both coins the numeral is shaped differently to UP8.
It is worth noting that a similar '3' also appears in the dates of other 1931 varieties that feature a Birmingham reverse. However, on close examination, the '3' in the Birmingham date varieties appears to be different to the '3' used in both the 1930 penny and UP8 (see below).
It is worth noting that a similar '3' also appears in the dates of other 1931 varieties that feature a Birmingham reverse. However, on close examination, the '3' in the Birmingham date varieties appears to be different to the '3' used in both the 1930 penny and UP8 (see below).
The '3' in the date of the Birmingham reverse die of the 1931 penny varieties (above) presents with a 'teardrop' end on the top curvature.
The top curvature of the '3' in the date of the UP8 (above) appears to terminate with a flat cut line. The '3' in the date of the 1930 penny also appears to terminate with a similar flat cut line.
Another interesting observation is that the dropped '1' in the date of UP8 is not in the same position as the dropped '1' found in other Unicorn Pennies (see below). If we define the space between the '3' and '1' in Unicorn Pennies as "wide date" (due to a more upright '1') then we can say that UP8 represents a "normal date" sub-strain.
Another interesting observation is that the dropped '1' in the date of UP8 is not in the same position as the dropped '1' found in other Unicorn Pennies (see below). If we define the space between the '3' and '1' in Unicorn Pennies as "wide date" (due to a more upright '1') then we can say that UP8 represents a "normal date" sub-strain.
A superimposed image of UP2 over UP8 (above) reveals the different placement of the dropped '1' in both coins. The difference in the '3' is also noted.
The above comparison reveals that at least two of the date numerals (the '3' and the rightmost '1') had been pressed into blank hubs (e.g. '19__') as individual numeral punches. However, irregularities such as the malformed base of the leftmost numeral '1' present evidence of additional alterations taking place.
The above comparison reveals that at least two of the date numerals (the '3' and the rightmost '1') had been pressed into blank hubs (e.g. '19__') as individual numeral punches. However, irregularities such as the malformed base of the leftmost numeral '1' present evidence of additional alterations taking place.
A further discovery of die markers in UP2 that can be traced to the 1929 penny [observation courtesy of F. Lever] points to the use of a 1929 reverse hub (see Image Gallery). This would have been a copy relief hub with leftmost '1', the '2' and the rightmost '9' removed. However, the fact that the 1929 die markers only appear in UP2 (i.e. these markers do not appear in any other Unicorn Penny) suggests that either multiple 1929 hub sources were used or that the processing of hubs/dies varied from one Unicorn Penny to another. That is, if the hubs/dies were properly annealed, polished and hardened, it would have been less likely for the markers to be visible on the struck coins. Accordingly, it is possible that more than one sub-strain of the Unicorn Penny exists; reflecting the minor adjustments in production methods. This is entirely expected in experimental coins.
A further discovery of die markers in UP2 that can be traced to the 1929 penny [observation courtesy of F. Lever] points to the use of a 1929 reverse hub (see Image Gallery). This would have been a copy relief hub with leftmost '1', the '2' and the rightmost '9' removed. However, the fact that the 1929 die markers only appear in UP2 (i.e. these markers do not appear in any other Unicorn Penny) suggests that either multiple 1929 hub sources were used or that the processing of hubs/dies varied from one Unicorn Penny to another. That is, if the hubs/dies were properly annealed, polished and hardened, it would have been less likely for the markers to be visible on the struck coins. Accordingly, it is possible that more than one sub-strain of the Unicorn Penny exists; reflecting the minor adjustments in production methods. This is entirely expected in experimental coins.
Origins
Origins
While numerous hypotheses are being considered to explain the origins of the Unicorn Penny, a common starting point is the production timeline for all of the 1931 penny varieties [Mullett, Crellin]. See below.
While numerous hypotheses are being considered to explain the origins of the Unicorn Penny, a common starting point is the production timeline for all of the 1931 penny varieties [Mullett, Crellin]. See below.
13th August 1931
13th August 1931
First Variety
First Variety
3rd - 10th September 1931
3rd - 10th September 1931
Second Variety
Second Variety
11th September 1931
11th September 1931
Third Variety
Third Variety
15th September 1931 -
15th September 1931 -
9th July 1932
9th July 1932
Fourth Variety
Fourth Variety
Indian obverse and Birmingham reverse.
Indian obverse and Birmingham reverse.
All of date numerals correctly formed and aligned.
All of date numerals correctly formed and aligned.
±46,000 struck
±46,000 struck
English obverse and a London reverse.
English obverse and a London reverse.
Blunt nose leftmost '1'; small void '9' and the dropped '1'.
Blunt nose leftmost '1'; small void '9' and the dropped '1'.
±300,000 struck
±300,000 struck
Indian obverse and a London reverse.
Indian obverse and a London reverse.
Blunt nose leftmost '1'; small void '9' and the dropped '1'.
Blunt nose leftmost '1'; small void '9' and the dropped '1'.
Less than 1000 struck
Less than 1000 struck
English obverse and Birmingham reverse.
English obverse and Birmingham reverse.
All of date numerals were correctly formed and aligned.
All of date numerals were correctly formed and aligned.
481,000 struck
481,000 struck
The above timeline reveals that after the Mint completed its relatively short run (±46,000) of the first variety coin (using a Birmingham reverse die) no additional pennies were struck for around three weeks. When production resumed, the Mint had suddenly switched to a London reverse die, which contained misaligned and mis-shaped date numerals that yielded the second variety coin. It is unclear what events transpired during the second half of August 1931 that compelled the Mint to hastily change the reverse die, but by the first week of September 1931 the Mint had decided to proceed with penny production (striking ±300,000 coins) despite the obvious imperfections.
The above timeline reveals that after the Mint completed its relatively short run (±46,000) of the first variety coin (using a Birmingham reverse die) no additional pennies were struck for around three weeks. When production resumed, the Mint had suddenly switched to a London reverse die, which contained misaligned and mis-shaped date numerals that yielded the second variety coin. It is unclear what events transpired during the second half of August 1931 that compelled the Mint to hastily change the reverse die, but by the first week of September 1931 the Mint had decided to proceed with penny production (striking ±300,000 coins) despite the obvious imperfections.
It is interesting that neither Mullett nor other commentators have noted any references among the Mint's official records to the rather prominent date numeral problem introduced by the London reverse die. This is not, however, entirely unexpected given that records were not meticulously maintained on all of the Mint's activities, and that the Mint was never particularly forthcoming about its blunders. There are copious examples of the Mint failing to reflect conspicuous events in its official records such as, for example, the release of the 1930 penny into circulation and the origin of 1933/2 overdate penny, which remains a mystery to date.
It is interesting that neither Mullett nor other commentators have noted any references among the Mint's official records to the rather prominent date numeral problem introduced by the London reverse die. This is not, however, entirely unexpected given that records were not meticulously maintained on all of the Mint's activities, and that the Mint was never particularly forthcoming about its blunders. There are copious examples of the Mint failing to reflect conspicuous events in its official records such as, for example, the release of the 1930 penny into circulation and the origin of 1933/2 overdate penny, which remains a mystery to date.
It is, of course, somewhat untenable to assume that the Mint had no knowledge of the 'dropped 1' defect, which appeared in the second variety coin. The defect was in fact so prominent that by the second week of September 1931 the Mint was ostensibly taking some hasty steps to correct it. The above timeline shows that within only one week of switching to the imperfect London reverse die, the Mint decided to switch the English obverse die for an Indian one. This decision suggests a somewhat chaotic state of activity, which led to the 'nil run' of the third variety coin using an Indian obverse and the defective London reverse dies. A few days later, however, the Mint reverted to the English obverse and Birmingham reverse die combination to yield the fourth variety coin, thereby resolving the problem of the improperly-shaped and misaligned date numerals.
It is, of course, somewhat untenable to assume that the Mint had no knowledge of the 'dropped 1' defect, which appeared in the second variety coin. The defect was in fact so prominent that by the second week of September 1931 the Mint was ostensibly taking some hasty steps to correct it. The above timeline shows that within only one week of switching to the imperfect London reverse die, the Mint decided to switch the English obverse die for an Indian one. This decision suggests a somewhat chaotic state of activity, which led to the 'nil run' of the third variety coin using an Indian obverse and the defective London reverse dies. A few days later, however, the Mint reverted to the English obverse and Birmingham reverse die combination to yield the fourth variety coin, thereby resolving the problem of the improperly-shaped and misaligned date numerals.
The above timeline observations support the premise that during the first half of September 1931, the Mint was taking urgent remedial steps that ultimately brought about the 1931 penny varieties. If this assertion is untrue, then the alternative is the rather fanciful idea of prominent defects going unnoticed by the Mint, and then being corrected within a short space of time by chance and pure coincidence.
The above timeline observations support the premise that during the first half of September 1931, the Mint was taking urgent remedial steps that ultimately brought about the 1931 penny varieties. If this assertion is untrue, then the alternative is the rather fanciful idea of prominent defects going unnoticed by the Mint, and then being corrected within a short space of time by chance and pure coincidence.
As for the dropped '1' numeral that appears in the second and third varieties of the 1931 penny, there is no question over it being pressed into to a '193_' type blank hub. This is evident from the hub containing a 'blunt nose' version of the '1' (leftmost date numeral), while the 'dropped 1' itself featured a 'pointy nose'. The Mint's records confirm that this hub was derived from a master die received from London earlier. Mullett also tells us that this master die was used as a source for producing a considerable number of hub derivatives, which points to the likelihood of extensive wear, resulting in the type of die distortions that caused the 'blunt nose 1' and the 'small void 9'.
As for the dropped '1' numeral that appears in the second and third varieties of the 1931 penny, there is no question over it being pressed into to a '193_' type blank hub. This is evident from the hub containing a 'blunt nose' version of the '1' (leftmost date numeral), while the 'dropped 1' itself featured a 'pointy nose'. The Mint's records confirm that this hub was derived from a master die received from London earlier. Mullett also tells us that this master die was used as a source for producing a considerable number of hub derivatives, which points to the likelihood of extensive wear, resulting in the type of die distortions that caused the 'blunt nose 1' and the 'small void 9'.
In attempting to address the date numeral problem observed in the second variety coin, it appears that the Mint suddenly realised that die distortion was the likely cause. Accordingly, it would have became clear that it could no longer continue relying on derivatives of the '193_' blank die, and would have needed to hastily consider a different approach. An obvious option was to turn to an alternative die source - most likely a redundant reverse die that contained correctly formed date numerals.
In attempting to address the date numeral problem observed in the second variety coin, it appears that the Mint suddenly realised that die distortion was the likely cause. Accordingly, it would have became clear that it could no longer continue relying on derivatives of the '193_' blank die, and would have needed to hastily consider a different approach. An obvious option was to turn to an alternative die source - most likely a redundant reverse die that contained correctly formed date numerals.
It is important to emphasise that during the first half of September 1931, the Mint was likely still trying to create an 'improved version' of the second variety coin. This is why the alternative die source had to be of the London type. It is submitted that the Mint selected a relief copy of a 1929 penny London reverse hub because it contained a perfectly formed leftmost '1' and leftmost '9'. It would have started preparing the die by removing the rightmost numerals '29'; grinding them down to make room for the numerals '31' to be added. However, since the gap between the remaining '1' and '9' in the resulting '19__' hub was wider than the standard gap in the '193_' master die, and therefore inconsistent with the very coin the Mint was trying to improve, the '1' seemingly also had to be ground down to accommodate the necessary adjustment. Ultimately, the Mint would have been left with a '_9__' blank incuse hub into which individual date numerals were to be pressed.
It is important to emphasise that during the first half of September 1931, the Mint was likely still trying to create an 'improved version' of the second variety coin. This is why the alternative die source had to be of the London type. It is submitted that the Mint selected a relief copy of a 1929 penny London reverse hub because it contained a perfectly formed leftmost '1' and leftmost '9'. It would have started preparing the die by removing the rightmost numerals '29'; grinding them down to make room for the numerals '31' to be added. However, since the gap between the remaining '1' and '9' in the resulting '19__' hub was wider than the standard gap in the '193_' master die, and therefore inconsistent with the very coin the Mint was trying to improve, the '1' seemingly also had to be ground down to accommodate the necessary adjustment. Ultimately, the Mint would have been left with a '_9__' blank incuse hub into which individual date numerals were to be pressed.
It is likely that production of the second variety coin had already begun by that time. This would explain why, in its attempt to correct the date numeral problem, it was important for the Mint to adhere to its commitment of using a London reverse die, and to retain the integrity of the original coin while attempting to improve it. Otherwise, instead of trying to correct the date numerals, it would have been much easier for the Mint to have simply produced an entirely new 1931 penny. Accordingly, the Mint experimented with the idea of transplanting the individual date numerals (i.e. the leftmost '1', the '3' and the dropped '1'), which were taken from either the second variety coin or its precursor relief hub, into the '_9__' blank incuse hub, using hand-made punches. This would have been a highly unconventional process with which the Mint had little experience.
It is likely that production of the second variety coin had already begun by that time. This would explain why, in its attempt to correct the date numeral problem, it was important for the Mint to adhere to its commitment of using a London reverse die, and to retain the integrity of the original coin while attempting to improve it. Otherwise, instead of trying to correct the date numerals, it would have been much easier for the Mint to have simply produced an entirely new 1931 penny. Accordingly, the Mint experimented with the idea of transplanting the individual date numerals (i.e. the leftmost '1', the '3' and the dropped '1'), which were taken from either the second variety coin or its precursor relief hub, into the '_9__' blank incuse hub, using hand-made punches. This would have been a highly unconventional process with which the Mint had little experience.
The resulting coin was the Unicorn Penny, which presented with a correctly formed '9' and an adjusted 'dropped 1' (more upright). Interestingly, no obvious attempt was made to correct the relatively minor defect in the form of the 'blunt nose 1'. This defect was seemingly overshadowed by the more significant problems observed in the other date numerals.
The resulting coin was the Unicorn Penny, which presented with a correctly formed '9' and an adjusted 'dropped 1' (more upright). Interestingly, no obvious attempt was made to correct the relatively minor defect in the form of the 'blunt nose 1'. This defect was seemingly overshadowed by the more significant problems observed in the other date numerals.
Sub-strains of the Unicorn Penny also appeared, showing evidence of further trials using different hand punches to create the date numeral '3' (see UP8 above).
Sub-strains of the Unicorn Penny also appeared, showing evidence of further trials using different hand punches to create the date numeral '3' (see UP8 above).
It is important to remember that the above corrections were most likely performed within a very limited time period and under considerable pressure to resume penny production as quickly as possible. Consequently, the attempt to produce an 'improved' second variety coin had, by all reasonable standards, failed. This is apparent from the numerous irregularities seen in the date numerals of the Unicorn Pennies.
It is important to remember that the above corrections were most likely performed within a very limited time period and under considerable pressure to resume penny production as quickly as possible. Consequently, the attempt to produce an 'improved' second variety coin had, by all reasonable standards, failed. This is apparent from the numerous irregularities seen in the date numerals of the Unicorn Pennies.
Ultimately, the rush to return to the presses meant that the Mint had little option but to abandon its attempt to improve the 1931 London reverse penny, end the imperfect run of the second variety coin, and resign to the considerably easier solution of producing a new 1931 penny by reverting to the Birmingham reverse die (i.e. the fourth variety coin).
Ultimately, the rush to return to the presses meant that the Mint had little option but to abandon its attempt to improve the 1931 London reverse penny, end the imperfect run of the second variety coin, and resign to the considerably easier solution of producing a new 1931 penny by reverting to the Birmingham reverse die (i.e. the fourth variety coin).
The few Unicorn Pennies that were 'hand-produced' during this brief period remain as a remnant of what can probably be best described as a rather shambolic episode in the history of the Melbourne Mint. At the same time, it can be said that the Unicorn Penny shines a light onto the mindset and resolve of the Mint's employees during arguably one of the most challenging periods in the nation's history.
The few Unicorn Pennies that were 'hand-produced' during this brief period remain as a remnant of what can probably be best described as a rather shambolic episode in the history of the Melbourne Mint. At the same time, it can be said that the Unicorn Penny shines a light onto the mindset and resolve of the Mint's employees during arguably one of the most challenging periods in the nation's history.
The Evidence
The Evidence
Evidence supporting the above hypothesis on the origins of the Unicorn Penny can be found through microscopic analysis (see below), which shows traces of activity associated with cutting numerals from a donor coin or hub, and hand-pressing them into a recipient hub.
Evidence supporting the above hypothesis on the origins of the Unicorn Penny can be found through microscopic analysis (see below), which shows traces of activity associated with cutting numerals from a donor coin or hub, and hand-pressing them into a recipient hub.
Microscopic analysis of UP2 (looking at the base of the leftmost date numeral '1' with 1000x magnification) shows the presence of a small ridge, which is visible when looking from the bottom upwards along the length of the numeral (Figure A). The ridge was likely formed during the process of removing the numeral from a donor coin or hub (see below). It indicates that during the pressing stage, the punch was allowed to sink into the hub surface below the intended level (i.e. the depth of the numeral punch itself). Moreover, the punch must have struck the hub at a slight angle, as traces of the ridge fade along the length of the numeral towards its top (Figure B). This observation also confirms that the numeral was independently pressed, since the ridge is unique to the leftmost '1'. The ridge line is not visible at the top of the numeral (Figure C), meaning that during pressing, the punch remained at its intended level above the surface of the hub. This supports the explanation that the punch struck the hub at a slight angle.
Microscopic analysis of UP2 (looking at the base of the leftmost date numeral '1' with 1000x magnification) shows the presence of a small ridge, which is visible when looking from the bottom upwards along the length of the numeral (Figure A). The ridge was likely formed during the process of removing the numeral from a donor coin or hub (see below). It indicates that during the pressing stage, the punch was allowed to sink into the hub surface below the intended level (i.e. the depth of the numeral punch itself). Moreover, the punch must have struck the hub at a slight angle, as traces of the ridge fade along the length of the numeral towards its top (Figure B). This observation also confirms that the numeral was independently pressed, since the ridge is unique to the leftmost '1'. The ridge line is not visible at the top of the numeral (Figure C), meaning that during pressing, the punch remained at its intended level above the surface of the hub. This supports the explanation that the punch struck the hub at a slight angle.
The ridge observed in the above analysis was most likely formed while the date numeral was being transferred from a donor source to the hub. Cutting the numeral from the surface of the donor coin (or a relief hub) would have involved the cutting tool penetrating deeper (under the numeral) into the body of the coin (or hub). This was done to ensure that the numeral was removed in one piece (see below).
The ridge observed in the above analysis was most likely formed while the date numeral was being transferred from a donor source to the hub. Cutting the numeral from the surface of the donor coin (or a relief hub) would have involved the cutting tool penetrating deeper (under the numeral) into the body of the coin (or hub). This was done to ensure that the numeral was removed in one piece (see below).
The excess metal under the numeral would have then been ground down to leave a flat base, enabling it to be evenly mounted onto the punch. However, in some areas, a microscopic amount of the excess metal (from the body of the coin) may have been left in place, creating a tiny ridge along the perimeter of the removed numeral (see illustration below).
The excess metal under the numeral would have then been ground down to leave a flat base, enabling it to be evenly mounted onto the punch. However, in some areas, a microscopic amount of the excess metal (from the body of the coin) may have been left in place, creating a tiny ridge along the perimeter of the removed numeral (see illustration below).
STEP 1
STEP 2
During the pressing stage, the ridge would have left an impression in the hub if the punch penetrated the surface beyond the depth of the numeral itself. This could have occurred either due to the ridge being unevenly sized along the perimeter of the numeral (particularly likely in the case of removing a curved numeral such as the '3') or due to the punch striking the hub surface at an angle (as seen with the leftmost '1' above).
During the pressing stage, the ridge would have left an impression in the hub if the punch penetrated the surface beyond the depth of the numeral itself. This could have occurred either due to the ridge being unevenly sized along the perimeter of the numeral (particularly likely in the case of removing a curved numeral such as the '3') or due to the punch striking the hub surface at an angle (as seen with the leftmost '1' above).
Once the hub was hardened to form a working die it was then used to strike the coins. Accordingly, the struck coins would have featured a very small ridge (visible under microscope) in some parts along the perimeter of the date numerals.
Once the hub was hardened to form a working die it was then used to strike the coins. Accordingly, the struck coins would have featured a very small ridge (visible under microscope) in some parts along the perimeter of the date numerals.
STEP 3
STEP 4
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