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DENTAL MKTATJA'RGY. 197 :
Capacity for Heat.*— l'^(|ual \vcii4lUs of (liffcreiu inelnls
require diffefent amounts of heat to raise tlieni from the
same to a higher given temperature. The amount of heat
necessary to raise one part hy weight of water from o C. to
I C. being 1, the amount of lieat required respectively to
raise the same weight of the following metals from o C.
to 1 C. will be as follows:

Specific Heat of Metals.!
Aluminum 0.2143 Tin 0.0562
Iron 0.1138 Antimony 0.0508
Nickel 0.1086 Alercury 0.0333
Zinc 0.0955 Platinum 0.0324
Copper 0.0952 Gold 0.0324
Palladium 0.0593 Lead 0.0314
Silver 0.0570 Bismuth 0.0308
Cadmium 0.0567

It will be seen from the above table that the capacity for
heat of the several metals is very variable. If small balls
of equal weights of different metals are exposed for the
same length of time to exactly the same temperature and
then withdrawn simultaneously and placed upon a thin
cake of wax, it will be observed that the metals having the
" "
greatest capacity for heat such as iron, will melt their
way through the wax much more rapidly than those hav-
ing a smaller capacity for heat.
Expansion by Heat.—Metals expand when heated,
though not uniformly. The degree of expansion, within
certain limits, is generally proportionate to the increase of
heat. Expansion can be considered from three standpoints
linear expansion, or expansion in one direction, superficial,
or expansions in two dimensions, and cubical or expansion
in three dimensions. This property is taken advantage of
in adopting metals for certain purposes. Zinc, for instance,
* Smith's Dental Metallurgy.
t Regnault, " Cours filementaire."