444 BOOK X. 



ounces of the alloy contain only five drachmae of copper or at most six, for 

 if there is more copper in it, the silver separated from the gold soon unites 

 with it again. Such molten silver containing gold is formed into granules, 

 being stirred by means of a rod split at the lower end, or else is poured into an 

 iron mould, and when cooled is made into thin leaves. As the process of 

 making granules from argentiferous gold demands greater care and diligence than 

 making them from any other metals, I will now explain the method briefly. The 

 alloy is tirst placed in a crucible, which is then covered with a lid and placed 

 in another earthen crucible containing a few ashes. Then they are placed 

 in the furnace, and after they are surrounded by charcoal, the fire is blown 

 bj? the blast of a bellows, and lest the charcoal fall away it is surrounded 

 by stones or bricks. Soon afterward charcoal is thrown over the upper 

 crucible and covered with live coals ; these again are covered with charcoal, 

 so that the crucible is surrounded and covered on all sides with it. It 

 is necessary to heat the crucibles with charcoal for the space of half an hour or 

 a little longer, and to provide that there is no deficiency of charcoal, lest the 

 alloy become chilled ; after this the air is blown in through the nozzle of the 

 bellows, that the gold may begin to melt. Soon afterward it is turned 

 round, and a test is quickly taken to see whether it be melted, and if it is 

 melted, fluxes are thrown into it ; it is advisable to cover up the crucible 

 again closely that the contents may not be exhaled. The contents are heated 

 together for as long as it would take to walk fifteen paces, and then the 

 crucible is seized with tongs and the gold is emptied into an oblong vessel 

 containing very cold water, by pouring it slowly from a height so that the 

 granules will not be too big ; in proportion as they are lighter, more fine 

 and more irregular, the better they are, therefore the water is frequently 

 stirred with a rod split into four parts from the lower end to the middle. 



The leaves are cut into small pieces, and they or the silver granules are 

 put into a glass ampulla, and the aqua is poured over them to a height of a 

 digit above the silver. The ampulla is covered with a bladder or with waxed 

 linen, lest the contents exhale. Then it is heated until the silver is dissolved, 

 the indication of which is the bubbling of the aqua. The gold remains in the 

 bottom, of a blackish colour, and the silver mixed with the aqua floats above. 

 Some pour the latter into a copper bowl and pour into it cold water, which 

 immediately congeals the silver ; this they take out and dry, having poured 

 off the aqua^''-. They heat the dried silver in an earthenware crucible until 

 it melts, and when it is melted they pour it into an iron mould. 



The gold which remains in the ampulla they wash with warm water, 

 filter, dry, and heat in a crucible with a little chrysocolla which is called 

 borax, and when it is melted they likewise pour it into an iron mould. 



" it until the lead has incorporated itself . . . blow it until it plickt (blickens). Then 

 " you will have as much silver as before." 



"The silver is apparently precipitated by the copper of the bowl. It would seem 

 that this method was in considerable use for small amounts of silver nitrate in the i6th 

 Century. Lazarus Ercker gives elaborate directions for this method (Besckreibiiiif; Aller- 

 furnemsten, etc., Prague, 1574, P- 77). 



