“I came a little sooner than I planned,” the newcomer admitted. “A business conference I had expected to attend was postponed until tomorrow. Naturally, that has upset my schedule. I had hoped you might consent to a demonstration of your machine tonight.”
“Tonight?” The professor seemed caught off guard. “But that is impossible!”
“Impossible?” inquired Mr. Johnson. “Why?”
“For one thing, my assistant is not here.”
“Can’t you get in touch with him?”
“I doubt it. Besides, I have another engagement.” The professor hesitated and added: “Officials of the Navy have invited me to confer with them tonight at the Gables Hotel in Riverview. I rather expect them to make me a very attractive offer for my invention.”
“But you promised me first option on it!” Mr. Johnson protested. “If necessary, I can wait for the demonstration tomorrow night, though it will greatly inconvenience me.”
“Tomorrow at eight o’clock,” the professor nodded. “If you should care to put up a small sum of money as a guarantee of your intentions, I promise to make no final deal with the Navy until after that time.”
“Why, yes,” Mr. Johnson agreed, taking out his check book. “Any amount you say.”
Feeling themselves no longer welcome by the Bettenridges, Penny and Louise slipped quietly away. As they climbed the hill they could hear the professor and Mr. Johnson discussing the amount to be paid.