Pix
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
A mode of testing coin. The ascertaining whether coin is of the proper standard is in England called "pixing" it; and there are occasions on which resort is had for this purpose to an ancient mode of inquisition called the "trial of the pix," before a jury of members of the Goldsmiths' Company. 2 Steph. Comm. 540, note.
— Pix jury. A j'ury consisting of the members of the corporation of the goldsmiths of the city of London, assembled upon an inquisition of very ancient date, called the "trial of the pix."