of every mass of separate form, if it be at all largely divided, is
to be expressed in terms of _miles_; and that every boiling heap of
illuminated mist in the nearer sky, is an enormous mountain, fifteen or
twenty thousand feet in height, six or seven miles over an illuminated
surface, furrowed by a thousand colossal ravines, torn by local tempests
into peaks and promontories, and changing its features with the majestic
velocity of the volcano.

Sec. 11. And consequent divisions and varieties of feature.

To those who have once convinced themselves of these proportions of the
heaven, it will be immediately evident, that though we might, without
much violation of truth, omit the minor divisions of a cloud four yards
over, it is the veriest audacity of falsehood to omit those of masses
where for yards we have to read miles; first, because it is physically
impossible that such a space should be without many and vast divisions;
secondly, because divisions at such distances must be sharply and
forcibly marked by aerial perspective, so that not only they must be
there, but they must be visible and evident to the eye; and thirdly,
because these multitudinous divisions are absolutely necessary, in order
to express this space and distance, which cannot but be fully and
imperfectly felt, even with every aid and evidence that art can give of
it.

Sec. 12. Not lightly to be omitted.

Now if an artist taking for his subject a chain of vast mountains,
several leagues long, were to unite all their varieties of ravine, crag,
chasm, and precipice, into one solid, unbroken mass, with one light side
and one dark side, looking like a white ball or parallelopiped two yards
broad, the words "breadth," "boldness," or, "generalization," would
scarcely be received as a sufficient apology for a proceeding so
glaringly false, and so painfully degrading. But when, instead of the
really large and simple forms of mountains, united, as they commonly
are, by some great principle of common organization, and so closely
resembling each other as often to correspond in line, and join in
effect; when instead of this, we have to do with spaces of cloud twice
as vast, broken up into a multiplicity of forms necessary to, and
characteristic of, their very nature--those forms subject to a thousand
local changes, having no association with each other, and rendered
visible in a thousand places by their own transparency or cavities,
where the mountain form