The Patio and Cazo Process. 



43 



space 0.20 m. between the bell and the wall, was then built 

 around it and fired with charcoal for fifteen hours, and removed 

 when cold. The yield of silver was about 200 kilos., and the 

 charcoal used about 250 kilos, per charge. This process is now 

 abandoned. 



In the more modern method, the strained amalgam is 

 charged into quicksilver-flasks from which the bottom has been 

 removed. Into these flasks others, open at both ends, are fitted so 

 that the lower parts are beneath the surface of the water, in a 

 tank placed under the furnace. The two flasks are luted so 

 that the quicksilver has no outlet except into the water, where it 

 condenses, as the screw in the upper part of the upper flask has 

 been firmly set. The inside of the flask is then washed, with 

 milk of lime or lined with brown paper, to prevent the silver 

 from adhering to the sides. To be sure that the amalgam 

 fills the whole flask, it is first rammed in, and then pounded 



HALF ELEVATION 



QUEMADERO FOR RETORTING SILVER AMALGAM. 

 Fig. 8. 



down with a heavy mallet. 30 to 35 kilos, are charged in each 

 of the flasks, which are then set aside to drain off the ex- 

 cess of quicksilver, and to allow the amalgam to harden. As 



