"I should like to have the experience," hesitated the secretary, "that is if you will not fly too high or too far."

"I'll take you across the Heath and back again and will keep within a tolerably safe distance from the ground."

"It's tempting," quavered Penn, wistfully, while Dan busied himself in getting things square. "Please yourself," rejoined Halliday carelessly, and satisfied that the timid man was nibbling at the bait. "I can't stay here all day." He slipped into the pilot's seat. "Well, well?"

"I really think I should like--where am I to sit?"

"In this place." Dan touched a spring and the pilot box of aluminium lengthened out so that there was room for two people. This was one of Vincent's improvements upon which he prided himself, as the vehicle could, by adjusting the closed-in car, seat two people or one, as the need arose. "But don't come, if you feel the least fear." Those of the idle spectators close at hand grinned at Penn's pale face, and he was stung into accepting hastily what he would have rejected in a cooler moment. "I am not afraid," he said, trying to steady his voice, and with an air of bravado he stepped in beside the aviator. "Oh, I say," he gasped. And no wonder. Dan did not give him a moment to change his mind. Having captured his prey, he intended to keep him, so set the engine going almost before Penn was comfortably seated. In less time than it takes to tell the aeroplane whirled along the ground swiftly and lifted herself gracefully upward. Penn gasped again, and glanced down at the sinking ground, where the spectators were already beginning to grow smaller. But the motion of the biplane was so easy, and the face of her pilot was so composed, that after the first thrill of terror Penn began to feel that flying was not such a very dangerous pastime as he had imagined. "Wonderful, wonderful," he murmured, as the great artificial bird glided smoothly through the air, "but don't--don't go too high, Mr. Halliday."

"I shall go high enough to smash you," said Dan, coolly. He was circling in swallow flights round the Heath, now high now low, now swift now slow, and had the machine so entirely under command that he was enabled to give a certain amount of his attention, though not all, to his companion. Penn gasped again, and his terror revived. "Smash me! Oh!!" he almost shrieked. "Yes," said Dan, not looking, since he had to watch where he was going, but speaking rapidly and clearly all the same. "I want to know the truth about that perfume. About the Sumatra perfume you told me was possessed alone by you. That was a lie, and you know it was a lie."

"I--I--I don't know anything more about it," whimpered the secretary. "Yes you do. Out with the truth," said Dan relentlessly, "if you don't I shall drop you overboard to smash like an egg." Penn clung to his seat desperately. "That would be murder."

"I daresay, but I shouldn't suffer. Accidents will happen in aeroplanes you know. You are like Mahomet's coffin, slung between heaven and earth, and overboard Mahomet's coffin will go in a few minutes unless----" Dan swerved the machine which tilted slightly and Penn went green with terror. "What--what--what do you want to know?" he wailed, as the biplane dipped nearly to earth, to sweep upward in a graceful curve. "Who is Mrs. Jarsell?"

"I--oh, Lord--I don't know."

"You do. She has this perfume also. Has it anything to do with a gang?"