CHAP. XXIII.

WEAR OF COIN.

187

If, then, the rate of loss by wear on gold moneywas at the rate of one part in six hundred, andthat money was one sixth of the circulating me-dium, and if the rate of loss on the silver moneywas at the rate of one part in one hundred andfifty, the mean rate of depreciation would be asnear to one part in three hundred and sixty ascan be calculated. The silver is estimated at onefourth greater degree of friction than our standardsilver, because it was at no time equal in finenessto our standards, and in most periods, and some-times for generations, vastly inferior.

Although the amount of silver in circulation asmoney at all times must have been greater thanthat of gold, yet, as the gold has six times thedurability of silver, the relative value of the twometals to each other could not be maintainedunless the mines produced the two metals in pro-portion to the loss on them by wear respectively.It seems probable that the due proportion waskept up during the existence of the Roman power,and through the dark ages which succeeded, tillthe discovery of America , and till the dispersionover the world of the excessive surplus produce ofsilver above that of gold. The value of gold tosilver had varied but little before the mines ofPotosi were discovered. Among the Romanse:old to silver seldom varied more than from nineto eleven for one, that is, a pound of gold wasrarely worth either more than eleven or less than