Finally, after several hours of work, the wireless was in shape to send and receive messages.  Tom pulled over the lever, and a crackling sound was heard, as the electricity leaped from the transmitters into space.  Then he clamped the receiver on his ear.

“All ready,” he announced.  “Has anybody any messages they wish sent?” For, with the courtesy of a true host he was ready to serve his guests before he forwarded his own wireless notes.

“Just tell my wife that I’m enjoying myself,” requested Mr. Damon.  “Bless my footstool!  But this is great!  We’re off the earth yet, connected with it.”

Mr. Jenks had no one to whom he wanted to send any word, but Mr. Parker wish to wire to a fellow scientist the result of some observations made in the upper air.

Tom noted all the messages down, and then, when all was in readiness he began to call his home station.  He knew that either his father or Mr. Jackson, the engineer, could receive the wireless.

But, no sooner had the young inventor sent off the first few dots and dashes representing “S.  I.”—­his home station call—­than he started and a look of surprise came over his face.

“They’re calling us!” he exclaimed.

“Who is?” asked Mr. Jenks.

“My house—­my father.  He—­he’s been trying to get us ever since we started, but I didn’t have the wireless in shape to receive messages.  Oh, I hope it’s not too late!”

“Too late!  Bless my soul, too late for what?” gasped Mr. Damon, somewhat alarmed by Tom’s manner.

The lad did not answer at once.  He was intently listening to a series of dots and dashes that clicked in the telephone receiver clamped to his left ear.  On his face there was a look of worriment.

“Father has just sent me a message,” he said.  “It’s a warning flashed through space!  He’s been trying to get it to me since yesterday!”

“What is it?” asked Mr. Jenks, rising from his seat.

“The mysterious man is aboard the airship—­hidden away!” cried Tom.  “That’s what Eradicate was trying to call to our attention as we started off.  Eradicate saw his face at a rear window, and tried to warn us!  The mysterious man is a stowaway on board!”

CHAPTER X—­DROPPING THE STOWAWAY

Tom’s excited announcement startled Mr. Damon and the others as much as if the young inventor had informed them that the airship had exploded and was about to dash with them to the earth.  The men leaped to their feet, and stared at the lad.

“A stowaway on board!” cried Mr. Damon.  “Bless my soul!  How did he—­”

“Are you sure that message is straight?” asked Mr. Jenks.  “Did Eradicate see the man?”

“He says he did,” answered Tom.  “The man is hidden away on board now—­probably among the stores and supplies.”

“Bless my tomato sauce!” exploded Mr. Damon.  “I hope he doesn’t eat them all up!”