474 



BOOK X. 



and thick ; with these he pushes the sticks of wood forward and the bars 

 then rest on the trestles. There are others who, when they separate metals, 

 put two such sticks of wood into the crucible through the aperture which is 

 between the bellows, as many through the holes at the back, and one through 

 the channel ; but in this case a larger number of long sticks of wood is 

 necessary, that is, sixty ; in the former case, forty long sticks of wood suffice 

 to carry out the operation. When the lead has been heated for two hours, 

 it is stirred with a hooked bar, that the heat may be increased. 



If it be difficult to separate the lead from the silver, he throws copper 

 and charcoal dust into the molten silver-lead alloy. If the alloy of argen- 

 tiferous gold and lead, or the silver-lead alloy, contains impurities from the 

 ore, then he throws in either equal portions of argol and Venetian glass or of 

 sal-ammoniac, or of Venetian glass and of Venetian soap ; or else unequal 

 portions, that is, two of argol and one of iron rust ; there are some who 

 mix a little saltpetre with each compound. To one centumpondium of the 

 aUoy is added a hes or a libra and a third of the powder, according 

 to whether it is more or less impure. The powder certainly separates the 

 impurities from the alloy. Then, with a kind of rabble he draws out through 



A— Furnace. B— Sticks of wood. C— Litharge. D— Plate. E— The foreman 



WHEN HUNGRY EATS BUTTER, THAT THE POISON WHICH THE CRUCIBLE EXHALES MAY NOT 

 HARM HIM, FOR THIS IS A SPECIAL REMEDY AGAINST THAT POISON. 



