bject. The task of the harbor stations, then, is to listen
both on a six-hundred-meter range, and one of nine hundred and
fifty-two--the first wave length for commercial and the latter for
Navy ship's calls. Then in response to inquiry the operator directs
the vessel how to enter that particular harbor, stating just where the
entrance buoys are and where the channel lies. If the man at the wheel
is new to the port this aid is invaluable."

"Not much like the navigation of the old days, is it?" mused Mr.
Crowninshield. "I should think such stations would put pilots out of
business."

"They do to some extent," was the reply. "There are, however, always
ships that cannot make a landing under their own steam, ships that
have to be towed. So the pilots still find something to do."

"And are these harbor stations on islands too?" questioned Nancy.

"Many of them are. A small proportion of them, though, are in
lighthouses. It all depends on which place has the more favorable
location."

"But do not the land stations that send messages sometimes interfere
with these stations?" queried Mr. Crowninshield.

"There are rules to prevent _that_," laughed Bob. "Of course the
difference in wave length to which the various types of stations are
limited solves a part of this difficulty. As I told you commercial
stations have their own particular wave length and must stick to it;
and private stations such as this one here have their range of two
hundred meters in which to operate and are confined to not more than
one kilowatt for sending messages. You cannot use more than this
without special permission from the Secretary of Labor. Should you do
so you are liable to a fine of one hundred dollars if your offense is
deliberate; if, however, it is proved that your apparatus was out of
adjustment and overreached itself you may get off with a
twenty-five-dollar fine. In that case you must see at once that your
radio error is corrected and your outfit set right."

"But sometimes along the coast aren't there big government stations
belonging to the army or navy? I should think these, with their press
of business, would butt in on the smaller ones and raise havoc with
them," ventured Mr. Crowninshield.

"Where there are such mix-ups and private or commercial stations
interfere with important government outfits the smaller ones are not
allowed to send messages during the first fifteen minutes of each
hour, such time being reserved for go