station, even approximately."

"On the contrary," replied Frank Brandon, "it is little more than a
matter of routine. Probably any of these radio fiends here could explain
the method as well as I can, but I'll try to make it plain to you.

"There is a certain type of aerial that has what we call 'directional'
properties, that is, when it is shifted around, the incoming signals
will be loudest when this loop aerial, as it is called, is directly in
line with the sending station. The receiving antenna is wound on a
square frame, and when the signals are received at their maximum
strength, we know that the frame is in a practically straight line with
the sending station we're after."

"Yes, but that still leaves you in the dark as to whether the station is
one mile away or a hundred miles," observed Mr. Fennington, as Brandon
paused.

"That's very true," answered the other. "And for that reason we can't
stop at using just one loop aerial. What we actually do is to have three
stations, each one equipped with a loop. These three stations are
located a good many miles apart. Now, with these three loops, we have
three lines of direction. We lay out these lines on a chart of the
territory, and where they intersect, is the place where the unlicensed
station is located. Is that clear?"

"Perfectly," said Mr. Fennington. "But what looks like a point on the
map may be a large space on the actual territory."

"Oh, yes, our work isn't done by any means after we have got our first
rough bearings," continued Brandon. "Having determined the approximate
position, we take the loops and receivers to what we know is a place
quite near the station we're after, and then we repeat the former
process. This time it is much more accurate. Gradually we draw the net
tighter until we find the antenna belonging to the offender, and
then--well, we make him wish he hadn't tried to fool the government."

"You certainly have it reduced to an exact science," acknowledged Mr.
Fennington. "I don't wonder that everybody interested in radio gets to
be a fanatic."

"We'll make a 'bug' out of you before we get through, Dad," declared
Herb, grinning.

"If my load of silk is recovered through the agency of radio, I'll be
enthusiastic enough over it to suit even you fellows," said his father.
"It will mean the best set that money can buy for you if I get it back."

"We'll hold you to that promise," threatened Herb. "Radio can do
anything," he added, wit