After a discussion of previous analyses of antoniniani issued around the middle of the third century A.D., the results of gravimetric analyses of four representative antoniniani of each of the three successive emperors are given. In order of their reigns the average silver content of the coins of these rulers was found to be 35.4%, 31.5%, and 17.9%, thus showing the rapid debasement that occurred in the decade after the middle of the century. Copper was the other major component of the coinage alloys, but small proportions of gold, tin, lead, iron, nickel, and zinc were present in all of them. -- AATA