“You never know,” said Fatty. “One of us might be captured in one mystery we solve, and we might want to get a message to the others. If we wrote it in invisible ink our enemies wouldn’t be able to read the message.”
Bets thought this sounded rather thrilling, though she didn’t very much want to be captured. Then a thought struck her.
“We’ll all have to carry an orange about with us, if ever we have enemies,” she said. “Won’t we? We’d better not take very juicy ones, or they’ll get squashed.”
“And we’d have to take a pen,” said Pip. “Well, I shan’t bother till we have enemies.”
“I shall,” said Fatty seriously. “You never know when you might need to write an invisible message. I take tons of things about with me in my pockets, just in case I might need them.”
This was quite true. The others were often amazed at the things Fatty carried about with him. As a rule he had practically anything needed in an emergency from a lemonade-bottle opener to a pocket-knife that contained twelve different kinds of tools.
“My mother goes through my pockets each night and won’t let me keep half what I want to,” said Pip.
“My mother never does things like that,” said Fatty. “She never bothers about my pockets.”
The others thought that it wasn’t only Fatty’s pockets his mother didn’t bother about - it was Fatty himself! He seemed to come and go as he pleased, missed his meals if he didn’t want them, went to bed what time he liked, and did more or less as he wanted to.
“Fatty, you said you’d show us how to get out of a locked room if the key wasn’t on your side,” said Bets, suddenly remembering. “There’s time to do that, too. Will you?”