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GOLD 177

tour and to be built out over long bevels to thin edges, and
also on account of greater familiarity on the part of modern

operators with its working properties.

METHOD OF WORKING COHESIVE GOLD

Annealing.—Annealing is for the purpose of driving off
volatile surface impurities, and rendering soft. There are

two methods, as follows, viz.,
1. Cut the gold into small pieces,
and lay on the tray of a gold annealer,
thus preventing contact with the im-
pure gases of the flame, as well as the

tendency to overheating and irregular
annealing. The best form of annealer
is the electric, though good results are
obtained with the ordinary forms, con-

structed for use on the alcohol lamp or
Bunsen burner (Fig. 192).
2. Grasp the gold near one end with
foil carriers, and pass back and forth
over the flame of an alcohol lamp or
Bunsen burner. Then grasp at another
Fig. -Kerr flame
point, and repeat the procedure, heating shield and gold "'annelier
^^^^ ^^"^^^^ ^^"^p-
the gold to a dull red color, being careful
not to overheat or melt any portion. There are three disadvan-
tages in this method, (a) The danger of overheating or melt-

ing the gold, rendering it brittle and destroying its softness,
(b) The danger of overheating one part and underheating
another, (c) The danger of gases from an impure gas flame,
or a charred wick of an alcohol flame, destroying some of the
natural cohesive property of the gold. The point first grasped

by the pliers is not annealed because the handles of the pliers
carry off the heat at that point, hence the necessity of grasp-
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