perty in common, but in
which one property was constantly related to many others; and that the
classification now current, places together in groups _supporters of
combustion_, _metallic and non-metallic bases_, _acids_, _salts_, etc.,
bodies which are often quite unlike in sensible qualities, but which are
like in the majority of their _relations_ to other bodies. In mineralogy
again, the first classifications were based upon differences in aspect,
texture, and other physical attributes. Berzelius made two attempts at a
classification based solely on chemical constitution. That now current,
recognises as far as possible the _relations_ between physical and
chemical characters. In botany the earliest classes formed were _trees_,
_shrubs_, and _herbs_: magnitude being the basis of distinction.
Dioscorides divided vegetables into _aromatic_, _alimentary_,
_medicinal_, and _vinous_: a division of chemical character. Caesalpinus
classified them by the seeds, and seed-vessels, which he preferred
because of the _relations_ found to subsist between the character of the
fructification and the general character of the other parts.

While the "natural system" since developed, carrying out the doctrine of
Linnaeus, that "natural orders must be formed by attention not to one or
two, but to _all_ the parts of plants," bases its divisions on like
peculiarities which are found to be _constantly related_ to the greatest
number of other like peculiarities. And similarly in zoology, the
successive classifications, from having been originally determined by
external and often subordinate characters not indicative of the
essential nature, have been gradually more and more determined by those
internal and fundamental differences, which have uniform _relations_ to
the greatest number of other differences. Nor shall we be surprised at
this analogy between the modes of progress of positive science and
classification, when we bear in mind that both proceed by making
generalisations; that both enable us to make previsions differing only
in their precision; and that while the one deals with equal properties
and relations, the other deals with properties and relations that
approximate towards equality in variable degrees.

Without further argument, it will, we think, be sufficiently clear that
the sciences are none of them separately evolved--are none of them
independent either logically or historically; but that all of them have,
in a greater or