Owing to the examination of the aeroplane, and the experimental flight to test its working order, time had passed uncommonly swiftly, and it was now fifteen minutes past one o'clock. Dan made up his mind to beard Curberry in his library, without waiting for the arrival of Queen Beelzebub, who, after all, might not arrive. His man and some willing onlookers wheeled the machine into the great shed, and the doors were about to be closed when one of the crowd uttered an exclamation, which was echoed by many others. Halliday, always on the alert for the unexpected, came quickly to the door of the building, and saw everyone looking upward and northward, to where a small black dot spotted the blue of the sky. It increased in size rapidly, and there was no difficulty in seeing that it was a flying-machine. At once a thought entered Dan's mind that there was Mrs. Jarsell on a Vincent biplane, paying her expected visit, although he had no reason to suppose that she was the pilot. Wondering if he was right or wrong in his surmise, he waited with a fast-beating heart, and became certain of the truth of his guess very shortly. Travelling at a great height, the strange biplane poised itself directly over the open space, and then began to drop slowly into the enclosed grounds of Lord Curberry's mansion. Not having field-glasses, Halliday could not make out if the pilot was a man or a woman, but, when the machine, cleverly managed, disappeared below the trees and walls of the park, he was convinced that Queen Beelzebub had arrived. At once he determined to make a third at her interview with Curberry, whatever objections might be raised. But first he arranged what to do in order to guard against future events of a dangerous nature. "Wheel my machine out again," he ordered the man and those who had assisted, "see that everything is in order, and have everything prepared to start. Do not let anyone touch this," and he tapped the aeroplane, "you understand?" "Yes, sir," said the man stolidly, "you're going for another fly?" "Exactly. The person who arrived is a friend of mine. I am going into yonder house to ask if a race can be arranged."