lass at school." This from the girl who had joyfully greeted the
Professor and the boys, yodeling a school yell from the hillside. Then
she shot an aside at the slim youth: "You're a regular, downright
simpleton, Thad, and forever looking for trouble. Don't listen to him,
Dad."

This appeared to settle the matter. Mr. Hooper squared his shoulders and
grinned broadly, adding: "Well, I ain't just satisfied 'bout them
knowin' how, but go to it your own way, Professor. I'm a goin' to watch
it, you know; not to interfere with your plans an' ways, but it's got to
be done right. If it goes along free an' fine, I ain't goin' to kick."

The Professor explained that they had further work to do on the plans
and must be going back. He took leave of Mr. Hooper and the daughter,
and retreated with the boys as hurriedly as Bill could manage his handy
crutch. They all proceeded silently in crossing the broad field, but
when in the road Bill had to voice his thoughts:

"I expect that old fellow'll make it too hot for us."

"Not for a minute; you need not consider that at all. Of course it would
be more satisfactory if Mr. Hooper could be assured at once of your real
ability, but it will have to grow on him. Just let him see what you can
do; that's all."

"I rather expect we can frame up something that will satisfy him and
Bill can spring it," said Gus.

"In just what way, can you imagine?" queried the Professor.

"Some geometrical stunt, maybe; triangulation, or--"

"Why, sure! That's just it!" exploded Bill. "I know how we can get him:
Parallax! Shucks, it'll be easy! Just leave it to me."

"Looks as though some kind of Napoleonic strategy were going to be
pulled off," asserted Professor Gray, laughing. "But, boys, keep in mind
that Mr. Hooper, while a rough-and-ready old chap, with a big fortune
made in cattle dealing, is really an uncut diamond; a fine old fellow at
heart, as you will see."

CHAPTER XI

ENGINEERING

Two busy days followed during which Bill and Gus went to the city with
Professor Gray to purchase materials in full for the power plant. They
also had cement, reinforcing iron, lumber for forms and a small tool
house hauled out to the power site and they drove the first stakes to
show the position of wheel and pipe line. Mr. Hooper did not put in an
appearance.

On the third morning the Professor bade the boys good-by, exacting the
promise that they would write frequently of their progress. They