CONSTITUENT MATERIALS OF THE EARTH AND OF THE OTHER BODIES OF SPACE.



The nebular hypothesis almost necessarily supposes matter to have
originally formed one mass. We have seen that the same physical laws
preside over the whole. Are we also to presume that the constitution
of the whole was uniform?--that is to say, that the whole consisted
of similar elements. It seems difficult to avoid coming to this
conclusion, at least under the qualification that, possibly, various
bodies, under peculiar circumstances attending their formation, may
contain elements which are wanting, and lack some which are present
in others, or that some may entirely consist of elements in which
others are entirely deficient.

What are elements? This is a term applied by the chemist to a
certain limited number of substances, (fifty-four or fifty-five are
ascertained,) which, in their combinations, form all the matters of
every kind present in and about our globe. They are called elements,
or simple substances, because it has hitherto been found impossible
to reduce them into others, wherefore they are presumed to be the
primary bases of all matters. It has, indeed, been surmised that
these so-called elements are only modifications of a primordial form
of matter, brought about under certain conditions; but if this should
prove to be the case, it would little affect the view which we are
taking of cosmical arrangements. Analogy would lead us to conclude
that the combinations of the primordial matter, forming our so-called
elements, are as universal or as liable to take place everywhere as