Stories of Inventors: The Adventures of Inventors and EngineersDoubleday, Russell
History
Stories of Inventors: The Adventures of Inventors and Engineers
Doubleday, Russell
Inventions; Inventors
In sending the message from one side of his father's estate at Bologna
to the other the young inventor used practically the same methods that
he uses to-day. Marconi's transmitting apparatus consisted of electric
batteries, an induction coil by which the force of the current is
increased, a telegrapher's key to make and break the circuit, and a
pair of brass knobs. The batteries were connected with the induction
coil, which in turn was connected with the brass knobs; the
telegrapher's key was placed between the battery and the coil. It was
the boy scarcely out of his teens who worked out the principles of his
system, but it took time and many, many experiments to overcome the
obstacles of long-distance wireless telegraphy. The sending of a message
across the garden in far-away Italy was a simple matter--the depressed
key completed the electric circuit created by a strong battery through
the induction coil and made a spark jump between the two brass knobs,
which in turn started the ether vibrating at the rate of three or four
hundred million times a minute from the tin box on top of a pole. The
vibrations in the ether circled wider and wider, as the circular waves
spread from the spot where a stone is dropped into a pool, but with the
speed of light, until they reached a corresponding tin box on top of a
like pole on the other side of the garden; this box, and the wire
connected with it, caught the waves, carried them down to the coherer,
and, joining the current from the local battery, a dot or dash was
recorded; immediately after, the tapper separated the metal particles
in the coherer and it was ready for the next series of waves.
One spark made a single dot, a stream of sparks the dash of the Morse
telegraphic code. The apparatus was crude at first, and worked
spasmodically, but Marconi knew he was on the right track and
persevered. With the heightening of the pole he found he could send
farther without an increase of electric power, until wireless messages
were sent from one extreme limit of his father's farm to the other.
It is hard to realize that the young inventor only began his experiments
in wireless telegraphy in 1895, and that it is scarcely eight years
since the great idea first occurred to him.
After a year of experimenting on his father's property, Marconi was able
to report to W.H. Preece, chief electrician of the British postal
system, certain definite facts--not theories, but facts. He had actually
sent and received messages, without the aid of wires, about two miles,
but the facilities for further experimenting at Bologna were exhausted,
and he went to England.
Public-domain text, read in full here on John Shaqi.
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