"No; I only took a passing glimpse. We'll turn in a few minutes and take a better look going back."
They went on. Lawrence shot a ptarmigan which would give colour to the ostensible object of their walk. Then they turned and retraced their steps. As they passed the buttress Bob looked carefully for the rope, and could just discern it by its slight motion against the background of rock.
"You might pass a dozen times and never notice it," he said.
Facing in the same direction as the current they were now able to take a more comprehensive view of the gorge.
"Where would you make your plunge if you wanted to swim across?" asked Bob.
Lawrence looked along the bank.
"There!" he said after a little, indicating a rock a few feet below and beyond them, that jutted out into the river.
"Well, let's go and take a look from there."
They left the track, climbed on to the rock, and sat down there with their knees up, flinging pebbles aimlessly into the water.
"I think you're right," said Bob. "Allowing for the strength of the current it's just about here that I should take the plunge. The oblique distance between this and the rope would make the diagonal--parallelogram of forces, you know."