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PLUGGING INSTRUMENTS. Ill ;

point of the instrument on a piece of cold polished
iron or steel is, that the heat there may be subject to
complete control. The precise shade will be governed
by the purpose for which the instrument is to be used
if for a drill, the edge or point should be of a light
straw color ; indeed, some operators prefer to have
them scarcely changed at the cutting edge, while ex-
cavators and chisels should be brought to a deep straw

or copper color ; this will be modified, however, by
the manner of working the steel, and its quality.
Skillfully hammering steel at a low heat—below a
red—adds much to its quality for a fine cutting instru-
ment, and gives an improved texture. Indeed, some
assert that those instruments that can be forged to
nearly their proper shape, can be as well, if not better,
tempered by the hammer as by any other means.
The instrument is then to be polished by the emery

wheel and dressed up with the oil-stone. Of the va-
rious methods of tempering, the foregoing is equal in
efficiency, and in convenience superior, to any other.

PLUGGING INSTRUMENTS.

For introducing and consolidating fillings, a great
variety of instruments is in use. In filling with gold
in some of the forms in which it is employed, the

plugging-pliers are required, for picking up the pieces
of gold and placing them in the proper positions in