The house of Marius, bought of Cornelia for $12,105, was sold to Lucullus for $80,760; the burning of his villa was a loss to M. Scaurus of $4,036,455; and Nero's golden house must have cost an immense sum, since Otho laid out in furnishing a part of it $2,017,225." But though Rome was greatly enriched by conquest, she never obtained possession of the chief wealth of Asia; and the largest quantity of the precious metals was always excluded from the calculations of ancient writers. The whole revenue of the Roman Empire under Augustus is "supposed to have been equal to 200 millions of our money;" and at the time of his death (A.D. 14) the gold and silver in circulation throughout the empire is supposed to have amounted to $1,790,000,000; which at a reduction of 1 grain in 360 every year for wear, would have been reduced by the year A.D. 482 to $435,165,495; and when the mines of Hungary and Germany began to be worked, during the seventh and ninth centuries, the entire amount of coined money was not more than about 42 at the former, and 165 or 170 million dollars at the latter, period; so that if no other supply had been obtained, the quantity then circulating would long since have been exhausted. "The loss by wear on silver" is shown by Mr. Jacob "to be four times that of gold;" that on our money is estimated at more than one part in a hundred annually; and "the smaller the pieces, the greater loss do they suffer by abrasion." "The maximum of durability of gold coins seems to be fixed at 22 parts, in 24, of pure gold with the appropriate alloys. When the fineness ascends or descends from that point, the consumption by abrasion is increased." It is from its ductility that gold wears so much less than silver; and many ancient gold coins (as those of Alexander and others), though evidently worn by use, nearly retain their true weight, from the surface being partly transferred into the adjacent hollows, and not entirely rubbed off as in silver. The quantity of the precious metals, formerly used for the purposes of luxury, greatly diminished after the decline of the Roman empire, and in the middle ages they were sparingly employed except for coinage; ornamental work in gold and silver, mostly executed by first-rate artists, being confined to men of rank, till the opening of new mines added to the supply; which was afterwards increased by the abundant treasures of America; and the quantity applied to ornamental purposes then began to vie with that of olden times. M. Leon Faucher even calculates the annual abstraction of the precious metals from circulation by use for luxury, disasters at sea, and export, at 25 million dollars, in Europe and the United States.