Ruding (ii. 102) states that at the close of the eighteenth century " the copper coinage of Ireland was in an infinitely better state compared with the silver coinage of England. The greater part of it, however, was not mint coin, but what was called Cammac's, being half pence made by a person of that name, a proprietor of copper mines, with a device upon it, not the King's face. "
Source: Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)