Vestiges of the Natural History of Creation | Page 9

respect to the conditions under which the
laws operate, and consequently the effects which they produce. Thus,
there may be substances here which are not in some other bodies, and
substances here solid may be elsewhere liquid or vaporiform. We are
the more entitled to draw such conclusions, seeing that there is nothing
at all singular or special in the astronomical situation of the earth. It
takes its place third in a series of planets, which series is only one of
numberless other systems forming one group. It is strikingly--if I may
use such an expression--a member of a democracy. Hence, we cannot
suppose that there is any peculiarity about it which does not probably
attach to multitudes of other bodies--in fact, to all that are analogous to

it in respect of cosmical arrangements.
It therefore becomes a point of great interest--what are the materials of
this specimen? What is the constitutional character of this object, which
may be said to be a sample, presented to our immediate observation, of
those crowds of worlds which seem to us as the particles of the desert
sand-cloud in number, and to whose profusion there are no conceivable
local limits?
The solids, liquids, and aeriform fluids of our globe are all, as has been
stated, reducible into fifty-five substances hitherto called elementary.
Six are gases; oxygen, hydrogen, and nitrogen being the chief.
Forty-two are metals, of which eleven are remarkable as composing, in
combination with oxygen, certain earths, as magnesia, lime, alumin.
The remaining six, including carbon, silicon, sulphur, have not any
general appellation.
The gas oxygen is considered as by far the most abundant substance in
our globe. It constitutes a fifth part of our atmosphere, a third part of
water, and a large proportion of every kind of rock in the crust of the
earth. Hydrogen, which forms two-thirds of water, and enters into some
mineral substances, is perhaps next. Nitrogen, of which the atmosphere
is four-fifths composed, must be considered as an abundant substance.
The metal silicium, which unites with oxygen in nearly equal parts to
form silica, the basis of nearly a half of the rocks in the earth's crust, is,
of course, an important ingredient. Aluminium, the metallic basis of
alumin, a large material in many rocks, is another abundant elementary
substance. So, also, is carbon a small ingredient in the atmosphere, but
the chief constituent of animal and vegetable substances, and of all
fossils which ever were in the latter condition, amongst which coal
takes a conspicuous place. The familiarly-known metals, as iron, tin,
lead, silver, gold, are elements of comparatively small magnitude in
that exterior part of the earth's body which we are able to investigate.
It is remarkable of the simple substances that they are generally in
some compound form. Thus, oxygen and nitrogen, though in union
they form the aerial envelope of the globe, are never found separate in
nature. Carbon is pure only in the diamond. And the metallic bases of

the earths, though the chemist can disengage them, may well be
supposed unlikely to remain long uncombined, seeing that contact with
moisture makes them burn. Combination and re-combination are
principles largely pervading nature. There are few rocks, for example,
that are not composed of at least two varieties of matter, each of which
is again a compound of elementary substances. What is still more
wonderful with respect to this principle of combination, all the
elementary substances observe certain mathematical proportions in
their unions. One volume of them unites with one, two, three, or more
volumes of another, any extra quantity being sure to be left over, if
such there should be. It is hence supposed that matter is composed of
infinitely minute particles or atoms, each of which belonging to any
one substance, can only (through the operation of some as yet hidden
law) associate with a certain number of the atoms of any other. There
are also strange predilections amongst substances for each other's
company. One will remain combined in solution with another, till a
third is added, when it will abandon the former and attach itself to the
latter. A fourth being added, the third will perhaps leave the first, and
join the new comer.
Such is an outline of the information which chemistry gives us
regarding the constituent materials of our globe. How infinitely is the
knowledge increased in interest, when we consider the probability of
such being the materials of the whole of the bodies of space, and the
laws under which these everywhere combine, subject only to local and
accidental variations!
In considering the cosmogenic arrangements of our globe, our attention
is called in a special degree to the moon.
In the nebular hypothesis, satellites are considered as masses thrown off
from their primaries, exactly as the primaries had