When these arrangements had been concluded, Professor Chadwick reached into a drawer of his desk, at which he was seated, in order to produce blotting paper to sign the contracts. But as he opened the drawer he suddenly paused, turned deathly pale, and pressed his hand to his forehead.
“What is the matter, are you ill?” cried the doctor in a concerned voice.
The boys, full of anxiety and alarm, repeated the question. But Professor Chadwick waved them aside.
“No, not ill,” he exclaimed in a strange voice. “Wait—wait! It is coming back to me now!”
He pressed a spring in his desk, and a secret drawer flew open. As it did so, they all uttered a shout of astonishment.
It contained the long-missing plans!
The mystery was soon explained. The Professor’s memory had come back to him with a rush when he opened the drawer for the blotting paper. On the day of the trial trip of the Electric Monarch, it will be recalled, he had been left behind. After the boys’ departure, (as it came back to him, he had begun to feel uneasy about the plans, secure though they seemed to be in the safe.)
He decided to find a better hiding place than the safe even, for them, and with that object in view arose from the lounge and opened the receptacle. Taking out the papers, he placed them in the secret drawer of the desk. Hardly had he done so, however, when an attack of vertigo seized him and he fell unconscious. Now that his memory had come back suddenly, as he seated himself once more at the desk, all became clear.
And so the mystery of the vanished plans was cleared up with satisfaction to all of them. After all, they had wrongfully suspected Hank and his allies, and they were glad to learn that their suspicions had been unfounded.
There is little more to tell. Heiny Dill finally evolved a burglar trap out of his invention, but he makes more money working for the Boy Inventors at High Towers than he does out of his numerous eccentric contrivances. Sam Hinkley returned to Nestorville not long after his invasion of New York, and after he had begged for forgiveness, his father finally gave him the post of night clerk in the hotel, which he fills admirably. Of the fate of Hank and Miles we are already informed.