Dr. Philip L. Mossman, M.D., talks about denominations of the St. Patrick coinage at COAC 2006
Channel: American Numismatic Society
Date: 2020-04-03

Philip L. Mossman discusses the production of the St. Patrick copper coinages with a view to determining the potential relationship between the large and small coppers and their probable original face values in Irish circulation. Analyzing the metrology of the coins in light of weight reduction through circulation, he estimates a full mint weight of 143.5 grains for the large planchet variety and 95.3 grains for the small planchet coin. With the support of textual evidence and taking into consideration the desire for profit by the unknown issuer(s), Mossman suggests that the small-planchet copper may have circulated originally as an Irish halfpenny of reduced size, which was subsequently (before 1724) devalued as a farthing. This was the same legal value given to the small-planchet variety by the West Jersey Assembly after quantities of St. Patrick coppers were brought to North America by the English Quaker, Mark Newby.

The presentation was part of the Coinage of the Americas Conference held at the American Numismatic Society on November 11th 2006.