“Won’t somebody disturb them?” inquired Ben.

“Why should anyone do that? Of course this queer layout will attract attention. No one will meddle with our little stations, though, for they will know they must be an equipment for some new experiments.”

The night watchman came forward to meet the boys as Ben emerged from the shed, a bag slung across his shoulders.

The officer leaned perplexedly on his cane and stood staring wonderingly at the singular outlay of boxes.

“Hello, Mr. Brown,” hailed Bob heartily. “Thought you had gone home, and we were stealing a march on you.”

“I’m waiting to be relieved by the day man. He’s a little late on duty,” explained the watchman. “What’s those boxes?”

“Oh, a big new idea, Mr. Brown,” declared Bob, with a mysterious air.

“No mischief, I hope?”

“Mischief?” repeated Bob with great gravity. “I should say not. If Ben and I don’t tumble out of the airship, those boxes will comprise a very original and remarkable experiment in the aviation line.”

“That so?” muttered the watchman in a puzzled way.