nd though the productions of the animal and vegetable kingdom
are much more submitted to the power of atmospheric agents than those of
the mineral kingdom, yet, as in the instances which have just been
mentioned, oxygen gradually destroys the equilibrium of the elements of
stones, and tends to reduce into powder, to render fit for soils, even
the hardest aggregates belonging to our globe. Electricity, as a
chemical agent, may be considered not only as directly producing an
infinite variety of changes, but likewise as influencing almost all which
take place. There are not two substances on the surface of the globe
that are not in different electrical relations to each other; and
chemical attraction itself seems to be a peculiar form of the exhibition
of electrical attraction; and wherever the atmosphere, or water, or any
part of the surface of the earth gains accumulated electricity of a
different kind from the contiguous surfaces, the tendency of this
electricity is to produce new arrangements of the parts of these
surfaces; thus a positively electrified cloud, acting even at a great
distance on a moistened stone, tends to attract its oxygenous, or
acidiform or acid, ingredients, and a negatively electrified cloud has
the same effect upon its earthy, alkaline, or metallic matter. And the
silent and slow operation of electricity is much more important in the
economy of Nature than its grand and impressive operation in lightning
and thunder. The chemical agencies of water and air are assisted by
those of electricity; and their joint effects combined with those of
gravitation and the mechanical ones I first described are sufficient to
account for the results of time. But the physical powers of Nature in
producing decay are assisted likewise by certain agencies or energies of
organised beings. A polished surface of a building or a statue is no
sooner made rough from the causes that have been mentioned than the seeds
of lichens and mosses, which are constantly floating in our atmosphere,
make it a place of repose, grow, and increase, and from their death,
their decay, and decomposition carbonaceous matter is produced, and at
length a soil is formed, in which grass can fix its roots. In the
crevices of walls, where this soil is washed down, even the seeds of
trees grow, and, gradually as a building becomes more ruined, ivy and
other parasitical plants cover it. Even the animal creation lends its
aid in the process of de