formed
by precipitation from this sea as the waters cooled; that even veins
have originated in this way; and that mountains are gigantic crystals,
not upheaved masses. In a word, he practically ignored volcanic action,
and denied in toto the theory of metamorphosis of rocks through the
agency of heat.

The followers of Werner came to be known as Neptunists; the Huttonians
as Plutonists. The history of geology during the first quarter of the
nineteenth century is mainly a recital of the intemperate controversy
between these opposing schools; though it should not be forgotten that,
meantime, the members of the Geological Society of London were making
an effort to hunt for facts and avoid compromising theories. Fact and
theory, however, were too closely linked to be thus divorced.

The brunt of the controversy settled about the unstratified
rocks--granites and their allies--which the Plutonists claimed as of
igneous origin. This contention had the theoretical support of the
nebular hypothesis, then gaining ground, which supposed the earth to be
a cooling globe. The Plutonists laid great stress, too, on the observed
fact that the temperature of the earth increases at a pretty constant
ratio as descent towards its centre is made in mines. But in particular
they appealed to the phenomena of volcanoes.

The evidence from this source was gathered and elaborated by Mr. G.
Poulett Scrope, secretary of the Geological Society of England, who, in
1823, published a classical work on volcanoes in which he claimed that
volcanic mountains, including some of the highest-known peaks, are
merely accumulated masses of lava belched forth from a crevice in the
earth's crust.

"Supposing the globe to have had any irregular shape when detached from
the sun," said Scrope, "the vaporization of its surface, and, of course,
of its projecting angles, together with its rotatory motion on its axis
and the liquefaction of its outer envelope, would necessarily occasion
its actual figure of an oblate spheroid. As the process of expansion
proceeded in depth, the original granitic beds were first partially
disaggregated, next disintegrated, and more or less liquefied,
the crystals being merged in the elastic vehicle produced by the
vaporization of the water contained between the laminae.

"Where this fluid was produced in abundance by great dilatation--that
is, in the outer and highly disintegrated strata, the superior specific
gravity of the crystal