Robert Matthews Coin Authentication


Coin Report No. USA 1


Coin submitted by: with held                             Date: 27th November 2002


Coin denomination: British one penny    Date:    1926   




The British bronze penny was introduced in 1860 to replace the copper penny. Its issued weight was 145.83 grains (9.4498 gram) and its diameter 30.81 mm. The reverse design was the traditional Britannia with a shield and trident. It was not until the Coinage Act 1870 that the coin specifications were defined in law. This Act called for a coin weight of 9.44984 gram with a plus or minus tolerance of 0.18899 gram. The composition called for an alloy of a mixed metal of copper, tin and zinc. No actual percentage of the metals was set. The diameter was not defined in law.


The Royal Mint used factory tolerances for the alloy of:


1860 to 1923: copper 95%, tin 4% and zinc 1%.

1923 to 1942: copper 95.5%, tin 3% and zinc 1.5%.


In 1894 the Britannia reverse was significantly modified. The new design did not contain the lighthouse and ship previously shown. This design remained essentially the same in 1926.


George V reigned between 6th May 1910 and 20th January 1936. Sir Bertram Mackennal designed the portrait, which was used on the obverse side of the coins struck in this reign. This obverse gave problems with “ghosting”, that is an impression of the head could be seen on the reverse side. Sir Bertram Mackennal modified the effigy to try to eliminate this ghosting. This modified effigy was used on the penny for some of 1926 coins and for the 1927 coins. It was not entirely successful and a completely new “small head” design by Sir Bertram Mackennal was introduced in 1928.


Main references:


“Coins of England and the United Kingdom”, 36th edition, Spink, London, 2001


“English Copper, Tin and Bronze Coins in the British Museum 1558 – 1958” by C.W. Peck, published by the British Museum, second edition 1970.


Description of the submitted coin


The coin had been cleaned and polished.




This had a well worn, left facing effigy of George V with little of the fine detail of the hair and beard remaining. It was possible to see a faint M on the truncation of the effigy, presumably the remains of the BM initials of the designer. There was a raised rim and toothed beading.



 The inscription was:




There was circulation damage and surface defects due to corrosion, although the corrosion products had mostly been removed presumably during the cleaning process.









This had a right facing Britannia sitting and holding a trident and shield. There was a date, 1926, below Britannia. Similar to the obverse there was a raised rim with toothed beading.


The inscription was: “ONE PENNY”. A lot of the fine detail was missing due to wear and corrosion.




This was plain.


Physical measurements


Weight: 8.977g             Diameter,  North/South:            30.77mm

     East/West:               30.78mm


Edge thickness: 1.58 to 1.68mm                       Alignment (Die axis):     ↑↑                    




Electrical conductivity: 20.2% IACS     Relative density: 8.83g/cc          Magnetic? No


X-ray fluorescence surface analysis:


Copper = 95.1%; tin = 2.9%; zinc = 1.9%; iron and nickel both less than 0.05%.


This x-ray fluorescence analysis was as expected for a 1926 British bronze coin. The relative density confirmed this. The electrical conductivity was lower than usually expect, 22 to 27% IACS. This was probably due to the presence of an impurity that was not included in the analytical program.


Microscopic examination




The obverse showed significant metal removal due to corrosion around the letters, DEI GRA : BRI.., and around the rear of the truncation. This made it almost impossible to see the initials, BM, of the designer. The B could not be seen and neither could any full stops.


Due to wear no fine detail of the hair or beard of the effigy could be seen.


All the details were consistent with a genuine coin.  




The bottom of the first vertical element of the first N of PENNY was missing.


The numerals in the date were as expected and had not been altered in any way.


All the details were consistent with a genuine coin.




This penny is a genuine coin with all aspects as expected.


Two variety of obverse design exist for this year, the original and modified designs. Coins with the modified design are scarce. Peck, see reference above, notes three diagnostic features to identify the modified design.


1.         “The hair, beard and moustache have been retouched.”


Comment: the wear on the coin means it was not possible to make any comparison on these features.


2.         “BM (in smaller letters and without stops) is placed nearer the back of

the neck.”


Comment: only the M can be seem and no stops. Comparing with a

1927 penny (modified design) the M appears nearer to the front of the neck.


3.         “The two dots of the colon are set farther apart.”


Comment: again comparing with a 1927 penny, the dots of the colon appear closer together. This is especially noticeable on the colon after “BRITT”.


Summarising, because of the amount of wear on the coin it is only possible to give a tentative opinion. This is that the obverse design is the unmodified and relatively common obverse design.




Robert W. Matthews C.Chem., MRSC

Formerly Queen’s Assay Master the Royal Mint

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