BOOK X. 445 



Some workers, into an ampulla which contains gold and silver and the 

 aqua which separates them, pour two or three times as much of this aqua 

 valens warmed, and into the same ampulla or into a dish into which all is 

 poured, throw fine leaves of black lead and copper ; by this means the gold 

 adheres to the lead and the silver to the copper, and separately the lead 

 from the gold, and separately the copper from the silver, are parted in a 

 cupel. But no method is approved by us which loses the aqua used to part 

 gold from silver, for it might be used again^^^. 



A glass ampulla, which bulges up inside at the bottom like a cone, is 

 covered on the lower part of the outside with lute in the way explained above, 

 and into it is put silver bullion weighing three and a half Roman librae. The 

 aqua which parts the one from the other is poured into it, and the ampulla is 

 placed in sand contained in an earthen vessel, or in a box, that it may be 

 warmed with a gentle fire. Lest the aqua should be exhaled, the top of the 

 ampulla is plastered on all sides with lute, and it is covered with a glass 

 operculum, under whose spout is placed another ampulla which receives the 

 distilled drops ; this receiver is likewise arranged in a box containing sand. 

 When the contents are heated it reddens, but when the redness no 

 longer appears to increase, it is taken out of the vessel or box and shaken ; 

 by this motion the aqua becomes heated again and grows red ; if this is 

 done two or three times before other aqua is added to it, the operation is sooner 

 concluded, and much less aqua is consumed. When the first charge has all 

 been distilled, as much silver as at first is again put into the ampvilla, for if 

 too much were put in at once, the gold would be parted from it with difl&culty. 

 Then the second aqua is poured in, but it is warmed in order that it and the 

 ampulla may be of equal temperature, so that the latter may not be cracked 

 by the cold ; also if a cold wind blows on it, it is apt to crack. Then the third 

 aqua is poured in, and also if circumstances require it, the fourth, that is to 

 say more aqua and again more is poured in until the gold assumes the colour 

 of burned brick. The artificer keeps in hand two aquae, one of which is 

 stronger than the other ; the stronger is used at first, then the less strong, 

 then at the last again the stronger. When the gold becomes of a reddish 

 yellow colour, spring water is poured in and heated until it boils. The gold is 

 washed four times and then heated in the crucible until it melts. The water 

 with which it was washed is put back, for there is a httle silver in it ; for 

 this reason it is poured into an ampulla and heated, and the drops first distilled 

 are received by one ampulla, while those which come later, that is to say 

 when the operculum begins to get red, fall into another. This latter aqua is 

 useful for testing the gold, the former for washing it ; the former may also 

 be poured over the ingredients from which the aqua valens is made. 



The aqua that was first distUled, which contains the silver, is poured into 

 an ampulla wide at the base, the top of which is also smeared with lute and 

 covered by an operculum, and is then boiled as before in order that it may be 

 separated from the silver. If there be so much aqua that (when boiled) it 



i^'We confess to a lack of understanding of this operation with leaves of lead and 

 copper. 



31 



