“You think so?” She picked up a discarded bit of paper and wrote something on it.
“Take this,” she commanded, and passed it to him. “Hold it until it’s dry. Convince yourself you can see no writing whatever. Then rake a hot stone from the camp fire and slowly heat the paper. I hope that will occupy you till I’ve finished.”
Falcon the Flunky carried out her instructions. Before he began heating the paper he could see only a faint glaze on its surface, which the casual observer would not have noticed at all. Now he pressed the paper to the hot stone, lifting it to cool it when it threatened to char; and gradually brown letters, clear and distinct, began to appear, till finally he found himself confronted by this:
Falcon the Flunky needeth a shave.
“By George!” he exclaimed. “I never knew that!”
“You should carry a pocket mirror,” murmured the girl, deep in her copying of the form letter she had written in pencil.
She finished the sixth invisible communication.
“You haven’t read to me what you are writing to Mart,” he pointed out.
She handed him the copy, and he read:
Dear Rattle-pod: You can’t imagine the fun we’re having. Too bad you are not in on it; but this will give you the chance to get in, after a fashion.