Alloys known to the Ancients, 79 



four fingers square. The other minerals, after their extrac- 

 tion, require the fire for their conversion into metal, but 

 gold of which we now treat, is gold as soon as it is found." 

 Again, *' Neither rust nor canker alters the weight of gold, 

 or affects in any way its quality. Salt and vinegar, though 

 such active solvents, do not make the least impression on it." 

 The above quotations go to shew, that many of the pro- 

 perties of gold were known at this period, and also that the 

 methods of extracting it from the earth were similar to those 

 employed at the present day. Pliny, however, gives us but 

 little information relative to its metallurgic treatment, ex- 

 cept that lead was employed in its purification, and also that 

 when found in lumps it was of itself pure, and required no 

 artificial refining. He also states, when speaking of the pro- 

 perties of mercury,* " So penetrating is this liquor, that there 

 is no vessel but it will eat and pass through. It supports every- 

 thing which may be thrown into it, unless it be gold only, 

 which sinks to the bottom. It is besides, very useful for the 

 purpose of refining gold ; to effect which object, that metal 

 mixed with cinders is placed in an earthen pot, and shaken 

 with mercury, which rejects all the impurities mixed with it, 

 but in return takes hold of the gold itself. To expel it from 

 the gold, the mixture is poured on skins, which on being 

 pressed, allow the mercury to pass through them in drops, 

 whilst the gold remains in all its purity." The above pro- 

 cess differs little from those in general use, for the purposes 

 of amalgamation, at the present day, but in this case also, 

 Pliny's description is very imperfect, inasmuch as the solid 

 amalgam remaining on the skins would require the separa- 

 tion of the combined mercury before the gold could exist in 

 the pure and fine state described. No mention is moreover 

 made of any means of separating gold from silver, or in 

 fact of their ever being found associated, except in an alloy 

 called electrum^\ said to be found in veins, and of which 

 an artificial kind was made by mixing one part of silver 

 and four parts of gold, and which appears to have been 

 anciently in great request, as Homer describes the palace 



* Pliny xxxiii., 6. \ Pliny xxxiii., 4. 



