he shed.
Then they all started for the house.

"Bless my umbrella! How it rains!" cried Mr. Damon, as he splashed on
through numerous puddles. "We got back just in time, Mr. Sharp."

"Where did you go?" asked the lad.

"Why we took a flight of about fifty miles and stopped at my house in
Waterfield for supper. Were you anxious about us?"

"A little when it began to storm," replied Tom.

"Anything new since we left?" asked Mr. Sharp, for it was the custom of
himself, or some of his friends, to take little trips in the airship.
They thought no more of it than many do of going for a short spin in an
automobile.

"Yes, there is something new," said Mr. Swift, as the party, all
drenched now, reached the broad veranda.

"Bless my gaiters!" cried Mr. Damon. "What is it? I hope the Happy
Harry gang hasn't robbed you again; nor Berg and his men tried to take
that treasure away from us, after we worked so hard to get it from the
wreck."

"No, it isn't that," replied Mr. Swift. "The truth is that Tom thinks
he has invented a storage battery that will revolutionize matters. He's
going to build an electric automobile, he says."

"I am," declared the lad, as the others looked at him, "and it will be
the speediest one you ever saw, too!"

CHAPTER III

THE MOTORCYCLE WINS

"Well, Tom," remarked Mr. Sharp, after a pause following the lad's
announcement. "I didn't know you had any ambitions in that line. Tell
us more about the battery. What system do you use; lead plates and
sulphuric acid?"

"Oh, that's out of date long ago," declared the lad.

"Well, I don't know much about electricity," admitted the aeronaut.
"I'll take my chances in an airship or a balloon, but when it comes to
electricity I'm down and out."

"So am I," admitted Mr. Damon. "Bless my gizzard, it's all I can do to
put a new spark plug in my automobile. Where is your new battery, Tom?"

"Out in my shop, running yet if it hasn't been frightened by the
airship smash," replied the lad, somewhat proudly. "It's an oxide of
nickel battery, with steel and oxide of iron negative electrodes."

"What solution do you use, Tom?" asked Mr. Swift. "I didn't get that
far in questioning you before the crash came," he added.

"Well I have, in the experimental battery, a solution of potassium
hydrate," replied the lad, "but I think I'm going to change it, and add
some lithium hydrate to it. I think that will make it stronger."

"Bless my watch chain!" ex