of
two, in another of four, in a third of eight, and in a fourth of
sixteen simple atoms.

The discovery of these facts immediately led to many most beautiful
and interesting results; they furnished us with a satisfactory
explanation of observations which were before veiled in mystery,--a
key to many of Nature's most curious recesses.

Again; solid bodies, whether simple or compound, are capable of
existing in two states, which are known by the terms amorphous and
crystalline.

When matter is passing from a gaseous or liquid state slowly into a
solid, an incessant motion is observed, as if the molecules were
minute magnets; they are seen to repel each other in one direction,
and to attract and cohere together in another, and in the end become
arranged into a regular form, which under equal circumstances is
always the same for any given kind of matter; that is, crystals are
formed.

Time and freedom of motion for the particles of bodies are necessary
to the formation of crystals. If we force a fluid or a gas to become
suddenly solid, leaving no time for its particles to arrange
themselves, and cohere in that direction in which the cohesive
attraction is strongest, no crystals will be formed, but the
resulting solid will have a different colour, a different degree of
hardness and cohesion, and will refract light differently; in one
word, will be amorphous. Thus we have cinnabar as a red and a
jet-black substance; sulphur a fixed and brittle body, and soft,
semitransparent, and ductile; glass as a milk-white opaque
substance, so hard that it strikes fire with steel, and in its
ordinary and well-known state. These dissimilar states and
properties of the same body are occasioned in one case by a regular,
in the other by an irregular, arrangement of its atoms; one is
crystalline, the other amorphous.

Applying these facts to natural productions, we have reason to
believe that clay-slate, and many kinds of greywacke, are amorphous
feldspar, as transition limestone is amorphous marble, basalt and
lava mixtures of amorphous zeolite and augite. Anything that
influences the cohesion, must also in a certain degree alter the
properties of bodies. Carbonate of lime, if crystallised at ordinary
temperatures, possesses the crystalline form, hardness, and
refracting power of common spar; if crystallised at a higher
temperature, it has the form and properties of arragonite.

Finally, Isomorphism, or the equality of form of man