and end elevations and tracings
were made of the same transferred to heavy manila paper. These were to
be placed on the varnished panels, so that holes could be bored through
paper and panel, thus insuring perfect spacing and arrangement.
Sketches, also, were made of all details.

The audion tubes, storage batteries and telephone receivers had been
purchased in the city. Almost all the other parts were made by the boys
out of carefully selected materials. The amplifiers consisted of iron
core transformers comprising several stages of radio frequency. The
variometers were wound of 22-gauge wire. Loose couplers were used
instead of the ordinary tuning coil. The switch arms, pivoting shafts
and attachments for same, the contact points and binding posts were
home-made. A potentiometer puzzled them most, both the making and the
application, but they mastered this rather intricate mechanism, as they
did the other parts.

In this labor, with everything at hand and a definite object in view, no
boys ever were happier, nor more profitably employed, considering the
influence upon their characters and future accomplishments. How true it
is that they who possess worthy hobbies, especially those governed by
the desire for construction and the inventive tendency, are getting
altogether the most out of life and are giving the best of themselves!

The work progressed steadily--not too hastily, but most satisfactorily.
Leaving at supper time, Bill's eyes would sparkle as he talked over
their efforts for that day, and quiet Gus would listen with nods and
make remarks of appreciation now and then.

"The way we've made that panel, Gus, with those end cleats doweled on
and the shellacking of both sides--it'll never warp. I'm proud of that
and it was mostly your idea."

"No, yours. I would have grooved the wood and used a tongue, but the
dowels are firmer."

"A tongue would have been all right."

"But, dear boy, the dowels were easier to put in."

"Oh, well, it's done now. To-morrow we'll begin the mounting and wiring.
Then for the aerial!"

But that very to-morrow brought with it the hardest blow the boys had
yet had to face. Full of high spirits, they walked the half mile out to
the Hooper place and found the garage a mass of blackened ruins. It had
caught fire, quite mysteriously, toward morning, and the gardener and
chauffeur, roused by the crackling flames, had worked like beavers but
with only time to push out the two automo