pe that some
of your dreams come true."

Her sons laughed good-naturedly; then Paul turned to his brother.
"Come on down in the basement, John," he said; "I wish to show you our
latest miniature model, the Sky-Bird. Another day's work ought to
finish it."

John followed him downstairs. In one corner of the large basement was
a good-sized workbench, lighted by two windows, and equipped with
several neatly-arranged shelves, which now held a divers collection of
chisels, bits, countersinks, etc. In a splendid oak cabinet attached
to the wall above was a more extensive array of wood- and metal-working
tools, some of which the brothers had bought with money earned at odd
jobs when they were still small boys. Since, they had added to their
set from time to time, as they needed this tool or that, until now few
professional mechanics could boast of a finer assortment.

Suspended from a hook directly over the bench was a beautiful six-foot
model of a racy-looking monoplane of peculiar and striking design. It
was glistening in several coats of spar-varnish, and so light and
delicate was its spidery frame that, as John reached out to take it in
his hand, the exhalation of his breath set it swaying away from him.

"My word, it's a light boy all right!" exclaimed John admiringly, as he
carefully took hold of the pretty thing. "That's just the feature
we've tried to get, too, Buddy,--lightness." He looked closely at the
long, graceful pair of wings, which were of an unusual thickness and a
slight upward thrust like those of a bird, and which widened batlike as
they ran back and joined the rear fuselage or body of the craft. "Have
you put the helium-gas in these wings yet, Paul, as we planned? I see
you have installed the valves. There's a valve in the after-fuselage,
too."

"The wings and fuselage are both filled," said Paul; "that is what
makes the Sky-Bird so light. If you had brought more helium the last
time you were here, I could have pumped in twice the quantity, I think,
and that would have made her so light she would rise of her own accord,
I really believe. As it is, she now weighs less than a half-ounce. I
had the scales on her yesterday."

John shared his brother's enthusiasm. "Fine!" he cried, with sparkling
eyes. "Why, that's almost a neutral condition, as she is! Buddy, if
we can apply this principle to a full-size machine--and I don't know
why we can't--we shall have solved the biggest problem fa