outside laid aside something that looked like an air pump. He applied one eye to a crack, and looked in on the sleeping watchman.
"He's off," the man murmured. "I thought he'd never get to sleep! Now to get in and dose those two lads! Then I'll have the place to myself!"
There was a clicking noise about the lock on the shed door. It was not a very secure lock at best, and, under the skilful fingers of the midnight visitor, it quickly gave way. The man entered. He gave one look at the slumbering watchman, listened to his heavy breathing, and then went softly toward the airship, which looked to be immense in the comparatively small shed—taking up nearly all the space.
The intruder peered in through the cabin windows where Ned and Tom were asleep. Once more there was in the atmosphere a sickish odor. The man again worked the instrument which was like a small air pump, taking care not to get his own face too near it. Presently he stopped and listened.
"They're doped," he murmured. He arose, and took from his mouth and nose a handkerchief saturated with some chemical that had rendered him immune to the effects of the sleep-producing gas that he had generated. "Sound asleep," he
