Fire was found to be but the visible and otherwise perceptible
indication of changes proceeding within the, so called, elements.

Lavoisier investigated the composition of the atmosphere and of
water, and studied the many wonderful offices performed by an
element common to both in the scheme of nature, namely, oxygen: and
he discovered many of the properties of this elementary gas.

After his time, the principal problem of chemical philosophers was
to determine the composition of the solid matters composing the
earth. To the eighteen metals previously known were soon added
twenty-four discovered to be constituents of minerals. The great
mass of the earth was shown to be composed of metals in combination
with oxygen, to which they are united in one, two, or more definite
and unalterable proportions, forming compounds which are termed
metallic oxides, and these, again, combined with oxides of other
bodies, essentially different to metals, namely, carbon and
silicium. If to these we add certain compounds of sulphur with
metals, in which the sulphur takes the place of oxygen, and forms
sulphurets, and one other body,--common salt,--(which is a compound
of sodium and chlorine), we have every substance which exists in a
solid form upon our globe in any very considerable mass. Other
compounds, innumerably various, are found only in small scattered
quantities.

The chemist, however, did not remain satisfied with the separation
of minerals into their component elements, i.e. their analysis; but
he sought by synthesis, i.e. by combining the separate elements and
forming substances similar to those constructed by nature, to prove