Mark promised him faithfully that when he and Bevis had done it first, he should come too if he would help them. Charlie gave in and agreed, but on condition that he should be taken for a sail first. Eager as Mark was for the island, it was no good trying to persuade Charlie, he adhered to his stipulation, and Mark had to yield. However, he reflected that if they took Charlie for a sail he would be certain to do as he promised, and besides that it would make Val jealous, and he and Charlie would quarrel, and so they would not be always watching. So it was settled--Charlie to have a sail, and then every afternoon at four o’clock he was to stand just above the quarry and wave a white handkerchief if all was right. If Bevis and Mark were missed he was to take off his hat, and wave that. As he had no watch, Charlie was to judge the time by the calling of the cows to be milked--the milkers make a great hullabaloo and shouting, which can be heard a long distance off. “I said we were going to live in the wood,” Mark told Bevis when he came back. “Then he won’t think we’re on the island. If he plays us any trick he’ll go and try and find us in the wood.” While Mark was gone about the signal, Bevis, thinking everything over, remembered the letter he had promised to write home. To post the letter one or other of them must go on the mainland, if by day some one would very likely see them and mention it, and then the question would arise why they came near without going home? Bevis went up to the cottage, and told Loo to listen every evening at ten o’clock out of her window, which looked over the field at the back, and if she heard anybody whistle three notes, “Foo-tootle-too,” to slip out, as it would be them. “That I will,” said Loo, delighted. “I’ll come in a minute.” Charlie had his sail next morning, but they took care not to go near the island. Knowing how sharp his eyes were, they tacked to and fro in Mozambique and Fir-Tree Gulf. Charlie learned to manage the foresail in five minutes, then the tiller, and to please him the more they let him act as captain for a while. He promised most faithfully to make the signal every day, and they knew he would do it.