The kid from Hagenmyer's waved his hand, then turned around and made his way briskly toward the fence.
"Who's this Hagenmyer, mate?" queried Ferral, drawing closer to his chum and looking at the latter curiously.
"He's the fellow that bought this balloon house from Brady," explained Matt. "That was before the police found out that Brady was a thief, but Brady knew the discovery was coming, so he got rid of everything he owned in South Chicago."
"What business has Hagenmyer got with you?"
"We'll know in a minute, Dick."
Matt tore off the end of the envelope and pulled out the enclosed sheet. He gave a low whistle as he read; then, after he had finished, he passed the letter over to Ferral. The communication ran as follows:
"Motor Matt: My workmen will begin tearing down the balloon house to-morrow morning. It will be necessary, therefore, for you to remove your air ship sometime this afternoon or to-night.
"Isidore Hagenmyer."
A look of satisfaction crossed Ferral's face.
"That means we've got to trip anchor and bear away," said he. "I'm not sorry. We've been hung up here for two weeks, old ship, and what good has it done us?"
"Not much, that's a fact," answered Matt discontentedly. "Hagenmyer has held off on tearing down the balloon house for that length of time, just to give us a safe place to keep the Hawk. We can't blame him for getting busy on the old shed to-morrow morning."