A plain of sad-coloured cloud lay along the level of the top of
the Cathedral dome, so that the ball and the cross looked like a
buoy riding on a leaden sea. As the flying ship swept towards it,
this plain of cloud looked as dry and definite and rocky as any
grey desert. Hence it gave to the mind and body a sharp and
unearthly sensation when the ship cut and sank into the cloud as
into any common mist, a thing without resistance. There was, as
it were, a deadly shock in the fact that there was no shock. It
was as if they had cloven into ancient cliffs like so much
butter. But sensations awaited them which were much stranger than
those of sinking through the solid earth. For a moment their eyes
and nostrils were stopped with darkness and opaque cloud; then
the darkness warmed into a kind of brown fog. And far, far below
them the brown fog fell until it warmed into fire. Through the
dense London atmosphere they could see below them the flaming
London lights; lights which lay beneath them in squares and
oblongs of fire. The fog and fire were mixed in a passionate
vapour; you might say that the fog was drowning the flames; or
you might say that the flames had set the fog on fire. Beside the
ship and beneath it (for it swung just under the ball), the
immeasurable dome itself shot out and down into the dark like a
combination of voiceless cataracts. Or it was like some cyclopean
sea-beast sitting above London and letting down its tentacles
bewilderingly on every side, a monstrosity in that starless
heaven. For the clouds that belonged to London had closed over
the heads of the voyagers sealing up the entrance of the upper
air. They had broken through a roof and come into a temple of
twilight.