at the ordinary temperature into which such
liquid air is poured, would be so hot compared with the coldness of the
liquid air, that as soon as the exceedingly cold liquid air came into
contact with the vessel, the comparatively hot vessel would make the
liquid air to boil.

ART. 36. _Three Divisions of Matter._--Matter has been divided into
three divisions, viz. solid, liquid, and gaseous. These divisions are
each known by characteristic qualities, which separate the one division
from another. At the same time, it is possible for matter to pass from
one division into another, as for example in the case of water, which
may exist in solid, liquid, and gaseous form. In view of the recent
researches of Sir. Wm. Crookes and Professor J. J. Thompson, it is very
probable that before long we shall have to add a fourth division to
matter, which we should have to call ultra-gaseous form, or it may
possibly be the aetherial form. If it should prove to be true that
Aether is matter, and possesses the essential qualities of matter as
suggested by Lord Kelvin, then certainly we shall have reached the
boundary of another great division of matter, and our conception of the
divisions of matter will have to be enlarged to take in that form, so
that matter would then be divided into four great divisions, viz. solid,
liquid, gaseous, and aetherial.

We will now consider the three groups as at present recognized.

_Solid._--Examples of solid bodies are common and familiar, and are
typified by such things as iron, silver, copper, and lead. The chief
characteristic of this condition of matter is that its condition or
state is fixed, and cannot be altered without the expenditure of heat or
electricity or some other form of energy.

All solid elementary substances, with the exception of carbon, can be
melted or reduced to a molten condition, although some of them require a
very high temperature to effect this reduction, as, for example,
platinum. When a still higher temperature is applied, the metals may be
vaporized, or reduced from a molten state to that of a vaporous
condition. In the case of solids, the atoms have not a free path in
which to move. It must not be thought, however, that the atoms of a
solid are motionless, as there is nothing absolutely motionless in the
universe. In the case of the solid, the molecules which compose it,
preserve their relative position and are linked together in relation to
each other by the force of