Plate Assay Act, 1783

If of 20 carats, maker's mark (20) & initials of his name,

and stamped in Dublin 3, in New Geneva 2 feathers.

IV. And be it further enacted, That no person shall sell, exchange, or export, or cause to be sold, exchanged or exported, any gold vessel, gold plate, or other manufacture of gold, being of the aforesaid standard of twenty carats fine, unless it be marked with the mark of the maker, which mark shall be the number (20,) and the first letter of the christian and sirname of the maker, nor unless it be likewise stamped at the assay-office in Dublin, with a plume of three feathers, or at the assay-office in New Geneva aforesaid, with a plume of two feathers only, under the like penalties as aforesaid.