52 TlMEHRI. 
An iron tube rises from the cover and bends down at an 
angle of 20 degrees. The balls of amalgam being placed 
in the bowl, wood ashes and clay mixed with water into 
a thick paste are applied as a lute to the edges, and the 
cover being fitted, the whole is firmly fixed by means of a 
clamp and set screw. The superfluous luting being 
removed, the retort is placed over a moderate fire. The 
end of the pipe is placed just below the surface of water 
conveniently placed, and if the fire is properly regulated 
the pipe need not be cooled. To prevent adhesion of 
gold to the retort, as may happen, the interior of the 
retort may be chalked, or the amalgam placed on a piece 
of paper. Two stakes driven into the ground, with a 
rod between their tops on which the retort is hung, with 
a fire of small wood built round it, is a convenient 
arrangement. When the retort is dull red hot, and no 
more mercury comes over, the fire is withdrawn and the 
retort allowed to cool. The bullion which ought to be 
metallic in appearance and of a gold color, is then ready 
to be melted. 
A caution is given not to open the retort before it is cool, 
nor to hasten its cooling by water, as great injury will 
accrue from the poisonous mercurial fumes. Larger quanti- 
ties of amalgam are refined in large cast iron retorts 
like those used in gas manufactories, with movable doors 
and arrangements for aiding condensation by water. 
Care in cleansing amalgam before putting it into the 
retort is essential — negle6l of this sometimes causes the 
bullion to be black, and attempts to remedy improperly 
retorted bullion by treatment with acids, are almost sure 
to result in loss. Any impurity in the bullion is best 
eliminated in the crucible when melting it. 
