fortunately to-night it
promises to be pretty bad. You see it has been a close, heavy day and
no doubt thunderstorms are in the air. A thunderstorm will kick up no
end of a rumpus with wireless."

"But we haven't had any thunderstorm," Nancy called above the hubbub.

"No, but somebody else's thunderstorm would bother us almost as
much," Bob explained good-humoredly.

"Never mind the thunderstorms now," put in Mr. Crowninshield. "Aren't
we going to hear anything but this whistling and groaning? Whee! There
it goes again. It is for all the world like a chorus of cats."

"It is more like a siren horn tooting up and down," laughed Nancy.

A spluttering crackle blotted out the wail.

"You would think they were frying doughnuts," grinned Dick, "wouldn't
you?"

"And you really believe a thunderstorm would cause a noise like this?"
queried Mrs. Crowninshield incredulously.

"It might. We have no way of knowing exactly what is raising the
trouble."

"Do you mean to say that a storm that wasn't round here at all
could----" burst out Jerry, then stopped embarrassed.

"Indeed it could," replied Bob, answering the unfinished question.
"You see thunderstorms cause powerful electrical waves that affect
apparatus miles and miles distant. Of course such waves vary in length
but nevertheless they act on all aerials to a greater or less degree.
Then, too, the atmospheric conditions are never quite identical,
changing with the hour of the day, the season of the year, and local
weather disturbances. Fortunately, since the air is positively
electrified and the earth negatively, certain of these differences are
remedied by the aerial that connects the two, the current discharges
partially seeping off through the ground. Sometimes, however, in spite
of every device used, such currents are strong enough to cause a roar
in the receiver. In addition there is the interference from other
radio stations which are busy transmitting messages, and although
there are rules that aim to reduce this annoyance, it is, to a certain
extent, always to be reckoned with."

"I should think somebody ought to invent something to prevent such
troubles," declared Nancy.

"Why don't you, Sis?" asked Dick wickedly.

"But it is terrible to have the air so full of noise," continued the
girl, as she made a little face at her brother. "I've always thought
of the air as being still."

"It is still in a general sense," smiled Bob. "It is only when the
ampl