CHAP. V. PRECIOUS METALS. 147 



less loss by friction on the gold coin at that than 

 at subsequent periods, on account of the great 

 purity of the metal. 



It is well known now, and seems to have been 

 ascertained at an early period, that the purer 

 the gold is, the less consumption of it from fric- 

 tion arises in use. Without examining the che- 

 mical reasons for this, the fact is undoubted, and 

 the ancients seem to have been acquainted with 

 it. They had early acquired the art of refining 

 it. We learn from Pliny 1 , that in his time gold 

 was refined by mercury, which mingled with it, 

 but rejected all alloy ; and the gold was after- 

 wards freed from the mercury by squeezing botli 

 in skins ; in which operation the mercury ran 

 through, and left the gold in a pure state. 



In the time of Philip of Macedon, the art of 

 refining had arrived at great perfection, for his 

 coins are found of the utmost purity ; and they 

 are rivalled by those of his son Alexander, and 

 of the other princes and cities which immedi- 

 ately followed. The purest gold coin now cir- 

 culating in Europe is that which issues from the 

 English mint. Our standard gold consists of 

 twenty-two carats of pure gold, and two carats of 

 alloy. That of all the other kingdoms of Europe 

 contains more alloy in different proportions ; 

 but except the Dutch ducats, which are few in 



1 Pliny, book xxxiii. 6. 



