epared in this way they
are orange-colored substances, though the mineral stibnite is
black.

~Metallic properties of antimony.~ The physical properties of the element
are those of a metal, and the fact that its sulphide is precipitated by
hydrogen sulphide shows that it acts like a metal in a chemical way.
Many other reactions show that antimony has more of the properties of a
metal than of a non-metal. The compound Sb(OH)_{3}, corresponding to
arsenious acid, while able to act as a weak acid is also able to act as
a weak base with strong acids. For example, when treated with
concentrated hydrochloric acid antimony chloride is formed:

Sb(OH)_{3} + 3HCl = SbCl_{3} + 3H_{2}O.

A number of elements act in this same way, their hydroxides under some
conditions being weak acids and under others weak bases.

ALLOYS

Some metals when melted together thoroughly intermix, and on cooling
form a homogeneous, metallic-appearing substance called an _alloy_. Not
all metals will mix in this way, and in some cases definite chemical
compounds are formed and separate out as the mixture solidifies, thus
destroying the uniform quality of the alloy. In general the melting
point of the alloy is below the average of the melting points of its
constituents, and it is often lower than any one of them.

Antimony forms alloys with many of the metals, and its chief commercial
use is for such purposes. It imparts to its alloys high density, rather
low melting point, and the property of expanding on solidification.
Such an alloy is especially useful in type founding, where fine lines
are to be reproduced on a cast. Type metal consists of antimony, lead,
and tin. Babbitt metal, used for journal bearings in machinery, contains
the same metals in a different proportion together with a small
percentage of copper.

BISMUTH

~Occurrence.~ Bismuth is usually found in the uncombined form in nature.
It also occurs as oxide and sulphide. Most of the bismuth of commerce
comes from Saxony, and from Mexico and Colorado, but it is not an
abundant element.

~Preparation.~ It is prepared by merely heating the ore containing the
native bismuth and allowing the melted metal to run out into suitable
vessels. Other ores are converted into oxides and reduced by heating
with carbon.

~Physical properties.~ Bismuth is a heavy, crystalline, brittle metal
nearly the color of silver, but with a slightly rosy tint which
distinguishes it from ot