“Well, I’m afraid we’ll have to build another Comet,” came from Jerry.

I will not tire you with a description of the voyage home. Sufficient to say that it was made, without accident, though once, when in deep water, a gigantic shark tried to ram the boat. But it was killed with the electric bomb gun, as the whale had been.

The boys and the three machinists were able to run the submarine to their entire satisfaction. After the first few days Jerry and his chums ran it alone, to get the experience. They also halted once, went to the bottom, and donned diving suits, for the professor wanted to get a few more specimens. He secured some rare ones.

“Oh, this has been a most fortunate trip for me!” he cried, with enthusiasm.

And finally the Sonderbaar entered Boston Harbor, creating no end of excitement. Great crowds watched her, and when her story was known the excitement increased. The boys were overwhelmed by reporters.

“But before we tell anything let them tell us if the old sailor was saved, and whether our airship was picked up,” stipulated Jerry.

“I can tell you about that,” volunteered an old reporter. “I had the story of both. Your airship was picked up, badly damaged, but in the main intact. Everyone supposed you were all drowned.”

“No wonder!” cried Bob. “We must send off telegrams at once to our folks.”

After this was done, and the safety of Mr. Sheldon and Grace told of to Bob’s mother, the newspaper men again begged for particulars of the remarkable voyage.

“First tell us—was that old sailor saved?” asked Ned.