y. And there are the
trolleys and electric railways that have been made possible. And the
incandescent electric lamp--how about that? Edison has turned his
wonderful genius only to those things that benefit millions of--"

"And he deserved to make millions out of it," said Ted.

"I guess he has, too," offered one of the girls.

"You bet, and that's what he works for: not just to benefit people,"
asserted Terry.

"I suppose your dad and most other guys got their dough all by accident
while they were trying to help other folks; eh?" Bill fired at Terry.

But the rich boy walked away, his usual method to keep from getting the
worst of an argument.

"Oh, I wish Grace Hooper were here," Cora said. "She's no snob like
Terry and wouldn't she enjoy this?"

"And her dad, too. Isn't he a nice old fellow, even though he's awfully
rich?" laughed Dot.

"He'd have his say about this argument, grammar or no grammar. He thinks
a lot of this chap he calls Eddy's son," Mary Dean declared.

"Great snakes! Does he really think the wizard is the child of some guy
named Eddy?" Ted queried.

"Sounds so," Cora said. "But you can't laugh at him, he's so kind and
good and it would hurt Grace. He would be interested in radio, too."

"Wonder he hasn't got a peach of a receiver set up in his house," Lucy
Shore ventured.

"Is he keen for all new-fangled things?" asked Ted.

"You bet he is, though somebody would have to tell him and show him
first. Well, people, I'm going home; who's along?"

With one accord the others got to their feet and started up or down the
street. Gus and Bill went together, as always; they had much to talk
about.

CHAPTER X

BRASS TACKS

On the day following the radio lecture, true to his promise, Professor
Gray led Bill and Gus to the broad acres of the Hooper estate and there,
with the plans before them, they went over the ground chosen for the
water-power site, comprehending every detail of the engineering task.
Professor Gray was more pleased than surprised by the ready manner in
which both lads took hold of the problem and even suggested certain
really desirable changes.

Bill indicated a better position fifty yards upstream for the dam and he
sketched his idea of making a water-tight flood gate which was so
ingenious that the Professor became enthusiastic and adopted it at once.

After nearly a whole day spent thus along the rocky defiles of the
little stream, eating their lunch beside