a time through the colossal metallic tracery of its supports, and came at
last above a place of moving platforms like the place into which Graham
had looked from the balcony. They crawled across the sloping transparency
that covered this street of platforms, crawling on hands and knees
because of the slipperiness of the snowfall.

For the most part the glass was bedewed, and Graham saw only hazy
suggestions of the forms below, but near the pitch of the transparent
roof the glass was clear, and he found himself looking sheerly down
upon it all. For awhile, in spite of the urgency of his guide, he gave
way to vertigo and lay spread-eagled on the glass, sick and paralysed.
Far below, mere stirring specks and dots, went the people of the
unsleeping city in their perpetual daylight, and the moving platforms
ran on their incessant journey. Messengers and men on unknown
businesses shot along the drooping cables and the frail bridges were
crowded with men. It was like peering into a gigantic glass hive, and
it lay vertically below him with only a tough glass of unknown
thickness to save him from a fall. The street showed warm and lit, and
Graham was wet now to the skin with thawing snow, and his feet were
numbed with cold. For a space he could not move. "Come on!" cried his
guide, with terror in his voice. "Come on!"

Graham reached the pitch of the roof by an effort.

Over the ridge, following his guide's example, he turned about and slid
backward down the opposite slope very swiftly, amid a little avalanche of
snow. While he was sliding he thought of what would happen if some broken
gap should come in his way. At the edge he stumbled to his feet ankle
deep in slush, thanking heaven for an opaque footing again. His guide was
already clambering up a metal screen to a level expanse.