Graham hesitated, went down upon all fours, crawled to the edge, and peered into a velvety blackness.  For a sickly moment he had courage neither to go on nor retreat, then he sat and hung his leg down, felt his guide’s hands pulling at him, had a horrible sensation of sliding over the edge into the unfathomable, splashed, and felt himself in a slushy gutter, impenetrably dark.

“This way,” whispered the voice, and he began crawling along the gutter through the trickling thaw, pressing himself against the wall.  They continued along it for some minutes.  He seemed to pass through a hundred stages of misery, to pass minute after minute through a hundred degrees of cold, damp, and exhaustion.  In a little while he ceased to feel his hands and feet.

The gutter sloped downwards.  He observed that they were now many feet below the edge of the buildings.  Rows of spectral white shapes like the ghosts of blind-drawn windows rose above them.  They came to the end of a cable fastened above one of these white windows, dimly visible and dropping into impenetrable shadows.  Suddenly his hand came against his guide’s. “Still!” whispered the latter very softly.

He looked up with a start and saw the huge wings of the flying machine gliding slowly and noiselessly overhead athwart the broad band of snow-flecked grey-blue sky.  In a moment it was hidden again.

“Keep still; they were just turning.”

For awhile both were motionless, then Graham’s companion stood up, and reaching towards the fastenings of the cable fumbled with some indistinct tackle.

“What is that?” asked Graham.

The only answer was a faint cry.  The man crouched motionless.  Graham peered and saw his face dimly.  He was staring down the long ribbon of sky, and Graham, following his eyes, saw the flying machine small and faint and remote.  Then he saw that the wings spread on either side, that it headed towards them, that every moment it grew larger.  It was following the edge of the chasm towards them.

The man’s movements became convulsive.  He thrust two cross bars into Graham’s hand.  Graham could not see them, he ascertained their form by feeling.  They were slung by thin cords to the cable.  On the cord were hand grips of some soft elastic substance.  “Put the cross between your legs,” whispered the guide hysterically, “and grip the holdfasts.  Grip tightly, grip!”

Graham did as he was told.

“Jump,” said the voice.  “In heaven’s name, jump!”

For one momentous second Graham could not speak.  He was glad afterwards that darkness hid his face.  He said nothing.  He began to tremble violently.  He looked sideways at the swift shadow that swallowed up the sky as it rushed upon him.

“Jump!  Jump—­in God’s name!  Or they will have us,” cried Graham’s guide, and in the violence of his passion thrust him forward.