I warrant he will know my cap, if he sees it.

He has an eye like a hawk and, if he sees anything outside one of the windows, he will suspect at once that it is a signal; and when he once looks closely at it, he will make out its orange tint and these three long cock's feathers." So saying, he thrust one of his arms through the bars with the cap, which he allowed to hang down against the wall below.

There he stood for two hours, closely examining every boat that came along.
At last he saw one rowed by two men, with a third sitting in the stern; and had no difficulty in making out, as it came closer, that this was Pierre, who was gazing at the castle.
Presently he saw him suddenly clap his hands, and speak to the rowers.

These did not look up, but continued to row on in the same leisurely way as before; nor did Pierre again glance at the castle.
Satisfied that his signal had been observed, Philip withdrew it, but continued to watch the boat.

It went half a mile higher up, then turned and floated quietly down the stream again.