It came down in a steep curve and swept round, wide wings extended and a trail of white condensing steam behind it, rose with an easy swiftness and went gliding up the air, swept horizontally forward in a wide curve, and vanished again in the steaming specks of snow.

And, through the ribs of its body, Graham saw two little men, very minute and active, searching the snowy areas about him, as it seemed to him, with field glasses.

For a second they were clear, then hazy through a thick whirl of snow, then small and distant, and in a minute they were gone.
"_Now_!" cried his companion.

"Come!" He pulled Graham's sleeve, and incontinently the two were running headlong down the arcade of iron-work beneath the wind-wheels.

Graham, running blindly, collided with his leader, who had turned back on him suddenly.