If the key were not depressed no
current flowed.
I presume most of you understand how the wireless works, so I will
not give you a complete description save to say that it is just like
a telegraph system, in fundamentals. The only difference is that
no connecting metallic wires are needed between stations.
A group of wires in parallels, called "aerials," are hung in the
air at one point, or station, and a similar set is suspended at the
other station. The electrical current jumps through the air from
one group of wires to the other, without being directly connected,
hence the name "wireless," though really some wires are used.
The electrical impulse can be sent for thousands of miles through
the air, without any directly connecting wires. And the method of
communication is by means of dots, dashes and spaces.
You have doubtless heard the railroad or other telegraph instruments
clicking. You can hold your table knife blade between two tines of
your fork, and imitate the sound of the telegraph very easily.
If you move your knife blade up and down once, quickly, that will
represent a dot. If you move it more slowly, holding it down for
a moment, that would be a dash. A space would be the interval
between a dot and a dash, or between two dots or two dashes.
Thus, by combinations of dots, dashes and spaces, the letters of
the alphabet may be made and words spelled out. For instance a dot
and a dash is "A."
In telegraphing, of course, the operator listens to the clicking of
the brass sounder in front of him on the desk.
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