E PI A DA.' 391 
consequence of our inquiry after antient medals, CHAP. 
several Venetian coins were offered to us ; and 
the number of them found here may serve to 
explain the origin of the castle, which was 
probably built by the Venetians. But besides 
these coins, the author purchased here, for 
twenty piastres, a most beautiful silver tetra- Greek 
drachm Qi Alexander the Great, as finely preserved Medals * 
as if it had just issued from the mint; 
together with some copper coins of Megara. 
The Greek silver medals, as it is well known, 
are often covered with a dark surface, in some 
instances quite black, resembling black varnish: 
the nature of this investment, perhaps, has not 
been duly examined: it has been sometimes 
considered as a sulphuret; but the colour which 
sulphur gives to silver is of a more dingy 
nature, inclining to grey: the black varnish is a 
muriat of silver 1 . It maybe decomposed by 
placing the medals in a boiling solution of 
(1) It once happened to the author to open a small case of Greek 
silver medals that had been sunk in sea-water. The medals had been 
separately enveloped in brown paper, which was now become dry. To 
his great surprise, he found every one of them covered with a fine 
impalpable powder, as white as snow. Placing them in a window, 
the action of the sun's rays turned this powder to a dark colour: when 
a brush was used to remove it, the silver became covered with a black 
shining varnish, exactly similar to that which covers the antient 
silver coinage of Greece ; and this proved to be a muriat of silver. 
