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240 MECHANICAL DENTISTRY AND METALLURGY
chilled l)y plunging it into water or some medium which will
rapidly abstract its heat. Water alone, or with the addition
of small proportions of acid or salt—the first to aid in the
separation of the scale or oxid, the latter to increase conduc-
tivity—is most commonly used, though in some instances
where extreme hardness is desired mercury is used, which,
on account of its superior conductivity, chills the heated
metal instantly. With water the chilling process is slower,
it being an inferior conductor, and when articles of con-
siderable size in a heated state are plunged into it actual
contact of the cold w^ater is prevented for a moment by the
formation of an envelope of steam, which surrounds the
hot metal and protects it. This does not occur when the
mercury bath is used.
The approximate temperatures corresponding to the
various tints are shown in the following" table:
Tem PERATURE. Color. Temper
430° to 450° F. Very faint yellow to Lancets, razors, surgical instru-
pale straw. ments, enamel chisels.
470° Full yellow. Excavators, very small cold-
chisels.
490° Brown. Pluggers, scissors, penknives.
510° Brown with pur pie Axes, plane-irons, saws, cold-
spots. chisels, etc.
530° Purple. Table-knives, large shears.
550° Bright blue. Swords, watch springs.
560° Full blue. Fine saws, augers.
600° Dark blue. Hand and pit saws.
ANTIMONY.
Symbol. Sb (Stibium). Atomic wciglif. 120.
Occurrence.—Antimony is found in the metallic state in
nature in various parts of the world. It is chiefly found,
however, as gray antimony ore, or sfibiiitc, which is a sul-
|)hid, Sl)oS;>, occurring most abundantly in CiM'uwall and
T lungary.
240 MECHANICAL DENTISTRY AND METALLURGY
chilled l)y plunging it into water or some medium which will
rapidly abstract its heat. Water alone, or with the addition
of small proportions of acid or salt—the first to aid in the
separation of the scale or oxid, the latter to increase conduc-
tivity—is most commonly used, though in some instances
where extreme hardness is desired mercury is used, which,
on account of its superior conductivity, chills the heated
metal instantly. With water the chilling process is slower,
it being an inferior conductor, and when articles of con-
siderable size in a heated state are plunged into it actual
contact of the cold w^ater is prevented for a moment by the
formation of an envelope of steam, which surrounds the
hot metal and protects it. This does not occur when the
mercury bath is used.
The approximate temperatures corresponding to the
various tints are shown in the following" table:
Tem PERATURE. Color. Temper
430° to 450° F. Very faint yellow to Lancets, razors, surgical instru-
pale straw. ments, enamel chisels.
470° Full yellow. Excavators, very small cold-
chisels.
490° Brown. Pluggers, scissors, penknives.
510° Brown with pur pie Axes, plane-irons, saws, cold-
spots. chisels, etc.
530° Purple. Table-knives, large shears.
550° Bright blue. Swords, watch springs.
560° Full blue. Fine saws, augers.
600° Dark blue. Hand and pit saws.
ANTIMONY.
Symbol. Sb (Stibium). Atomic wciglif. 120.
Occurrence.—Antimony is found in the metallic state in
nature in various parts of the world. It is chiefly found,
however, as gray antimony ore, or sfibiiitc, which is a sul-
|)hid, Sl)oS;>, occurring most abundantly in CiM'uwall and
T lungary.
