His head reappeared.

"It is a ledge," he whispered.

"In the dark all the way along.

Do as I did." 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.