eneous state in which it was composed of one or a few
types of matter, to that relatively-heterogeneous state in which it is
composed of many types of matter very diverse in their properties. This
deduction from the law which holds throughout the cosmos as now known to
us, would have much weight even were it unsupported by induction; but a
survey of chemical phenomena at large discloses several groups of
inductive evidences supporting it.

The first is that since the cooling of the Earth reached an advanced
stage, the components of its crust have been ever increasing in
heterogeneity. When the so-called elements, originally existing in a
dissociated state, united into oxides, acids, and other binary
compounds, the total number of different substances was immensely
augmented, the new substances were more complex than the old, and their
properties were more varied. That is, the assemblage became more
heterogeneous in its kinds, in the composition of each kind, and in the
range of chemical characters. When, at a later period, there arose salts
and other compounds of similar degrees of complexity, there was again an
increase of heterogeneity, alike in the aggregate and in its members.
And when, still later, matters classed as organic became possible, the
multiformity was yet further augmented in kindred ways. If, then,
chemical evolution, so far as we can trace it, has been from the
homogeneous to the heterogeneous, may we not fairly suppose that it has
been so from the beginning? If, from late stages in the Earth's history,
we run back, and find the lines of chemical evolution continually
converging, until they bring us to bodies which we cannot decompose, may
we not suspect that, could we run back these lines still further, we
should come to still decreasing heterogeneity in the number and nature
of the substances, until we reached something like homogeneity?

A parallel argument may be derived from consideration of the affinities
and stabilities of chemical compounds. Beginning with the complex
nitrogenous bodies out of which living things are formed, and which, in
the history of the Earth, are the most modern, at the same time that
they are the most heterogeneous, we see that the affinities and
stabilities of these are extremely small. Their molecules do not enter
bodily into union with those of other substances so as to form more
complex compounds still, and their components often fail to hold
together under ordinary